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Comparison of terrestrial and marine records of changing climate of the last 500,000 years
Abstract
A broad correspondence between long pollen sequences and the deep-sea oxygen isotope record has been noted for some time, but there has been little effort to explore just how similar the two types of evidence are in terms of their overall structure on glacial-interglacial timescales and also how they may differ. These questions have profound importance both for how we view the stratigraphic record of changing climate in different regions and for our understanding of the climate system. Here we link the four longest European pollen records and derive a terrestrial sequence of vegetation events and a coherent stratigraphic scheme for the last 500,000 years. Comparison of the terrestrial and marine records shows good agreement, but it also reveals that the pollen sequences contain a higher degree of climate sensitivity than the oxygen isotope record. In addition, it suggests that neither an oxygen isotope record nor a Milankovitch-forced ice volume model may provide an appropriate template for fine-tuning the terrestrial record and that better chronologies will depend on an improved understanding of controls on sedimentation rates in individual sedimentary basins.
... The palynological record of Lake Ohrid is most suited for this purpose due to its robust and vegetation-independent chronology Zanchetta et al., 2016;Wagner et al., 2017Wagner et al., , 2019. The previous age-depth model of the Velay record was established by correlating the Velay composite profile with the marine SPECMAP curve (Imbrie et al., 1984) using glacial-to-deglacial transitions as tie points (Tzedakis et al., 1997). However, more recent pollen data (Reille et al., 2000) were not included for establishing this previous chronology. ...
... The previous age-depth model was established by correlating the Velay composite profile with the marine SPECMAP curve (Imbrie et al., 1984) using glacial-to-deglacial transitions as tie points (Tzedakis et al., 1997). For the oldest part (287-430 ka) of the composite profile, pollen data of the core Pra 1995 (Reille and Beaulieu, 1995) that was drilled at Praclaux was used. ...
... We use the arboreal pollen excluding Pinus (AP-Pinus) signal of the latest long sequence from Lake Ohrid (Donders et al., 2021) as tuning target (Fig. 2). Following the original approach of Tzedakis et al. (1997), we excluded Pinus from the terrestrial pollen sum of the Velay composite profile. To determine tie points (n = 19), we used visual criteria, i.e., the onset of the steep increase (rational pollen limit; see Lang et al., 2023) and decrease of AP-Pinus at the beginning and the end of interglacials/interstadials. ...
... MIS 11 is therefore important as an analogue for current and future climate scenarios. An important aspect of this work is how global temperature changes affect terrestrial biota, which can be addressed through the correlation of marine and terrestrial records (Tzedakis et al., 1997;Desprat et al., 2005;Wu et al., 2007). It has become increasingly clear that there is a much more complex relationship between the often fragmented terrestrial record and the marine and ice records. ...
... Only recently has it been possible to recognise these complex changes in the terrestrial record, particularly in southern Europe where pollen sequences have enabled correlation with marine isotope substages (Reille and de Beaulieu, 1995;Tzedakis et al., 1997;de Beaulieu et al., 2001;Desprat et al., 2005;Tzedakis et al., 2006). In Britain, such sequences have not been found, and most palynological records are of relatively short duration (cf. ...
... Given the climatic complexity of MIS 11 (e.g. Bassinot et al., 1994;Tzedakis et al., 1997;Petit et al., 1999;Desprat et al., 2005) they could be correlated with later cold and warm events in MIS 11, or alternatively with even younger cold and warm episodes. ...
A terrestrial (lacustrine and fluvial) palaeoclimate record from Hoxne (Suffolk, UK) shows two temperate phases separated by a cold episode, correlated with MIS 11 subdivisions corresponding to isotopic events 11.3 (Hoxnian interglacial period), 11.24 (Stratum C cold interval), and 11.23 (warm interval with evidence of human presence). A robust, reproducible multiproxy consensus approach validates and combines quantitative palaeotemperature reconstructions from three invertebrate groups (beetles, chironomids, and ostracods) and plant indicator taxa with qualitative implications of molluscs and small vertebrates. Compared with the present, interglacial mean monthly air temperatures were similar or up to 4.0°C higher in summer, but similar or as much as 3.0°C lower in winter; the Stratum C cold interval, following prolonged nondeposition or erosion of the lake bed, experienced summers 2.5°C cooler and winters between 5°C and 10°C cooler than at present. Possible reworking of fossils into Stratum C from underlying interglacial assemblages is taken into account. Oxygen and carbon isotopes from ostracod shells indicate evaporatively enriched lake water during Stratum C deposition. Comparative evaluation shows that proxy-based palaeoclimate reconstruction methods are best tested against each other and, if validated, can be used to generate more refined and robust results through multiproxy consensus.
... The long successions in these basins preserve lithological, biological, and geochemical records of past environmental changes which, together with the identification of climatic and physical events such as magnetic reversals and tephra strata, can be correlated to global as well as regional stratigraphies (e.g., Hooghiemstra and Sarmiento, 1991). The correlation is achieved by defining individual climatic or chronostratigraphies for each basin that are then compared and correlated with external records, mainly the marine isotope record (e.g., Tzedakis et al., 1997Tzedakis et al., , 2006. For example, the Siberian Lake Baikal provides a bioproductivity record from the center of the world's largest landmass an area of extreme continental climate. ...
... Thus these correlations must rely on direct dating or less reliably on the technique of "curve matching," a widely used approach in the Quaternary. The latter can only reliably be achieved where long, continuous terrestrial successions are available, such as Long Lake records (e.g., Tzedakis et al., 1997), but even here it is not always straightforward (e.g., Watts et al., 1995) because of overprinting by local factors. Moreover, the possibility of failure to identify "leads-and-lags" in timing by the matching of curves is very real. ...
... These detritus bands can provide important lithostratigraphic markers for intercore correlation in ocean sediments, and the impact of their accompanying sudden coolings (Heinrich events) may be recognizable in certain sensitive terrestrial successions such as ice cores and speleothems (Fig. 30.14). Similarly, the essentially timeÀparallel periods of abrupt climate change termed "terminations" (Broecker and Van Donk, 1970), seen in marine isotope records (Fig. 30.2), can also be recognized on land as sharp changes in pollen assemblage composition or other parameters, for example, where sufficiently long and detailed successions are available, such as in Long Lake cores (see Tzedakis et al., 1997) and in speleothems (Cheng et al., 2009;see Fig. 30.16). However, their value for correlation may be limited in high-sedimentation-rate successions because these "terminations" are not instantaneous but have durations of several thousand years (Broecker and Henderson, 1998). ...
The Quaternary System/Period, comprising the Holocene and Pleistocene series/epochs, encompasses the last ~2.6 Myr during which time Earth’s climate was strongly influenced by bipolar glaciation, and the genus Homo first appeared and diversified. The base of the Quaternary System and Pleistocene Series is defined by the Global Boundary Stratotype Section and Point (GSSP) for the Gelasian Stage at Monte San Nicola in Italy with an age of 2.58 Ma. The Calabrian Stage of the Lower Pleistocene Subseries is defined by a GSSP at the Vrica section, also in Italy, with an age of 1.80 Ma. The Chibanian Stage of the Middle Pleistocene Subseries is defined by a GSSP at the Chiba section in Japan with an age of 0.774 Ma. The Upper Pleistocene subseries is defined in name only with an age of ~129 ka. The base of the Holocene Series is defined in the NGRIP2 Greenland ice core with an age of 11 700 years b2k (before CE 2000). The Holocene is subdivided into lower, middle, and upper subseries and their corresponding Greenlandian, Northgrippian, and Meghalayan stages. The Northgrippian Stage is defined by a GSSP in the NGRIP1 Greenland ice core with an age of 8.2 ka, and the Meghalayan Stage by a GSSP in a speleothem from India with an age of 4.2 ka. These are the only GSSPs ever to be defined in an ice core or a speleothem.
... Furthermore, in most cases, there has been a lack of independent chronologies. In this regard, Tzedakis et al. (1997Tzedakis et al. ( , 2001) established a terrestrial chronological framework for long and continuous pollen records in Europe (Velay, Valle di Castiglione, Ioannina and Tenaghi Philippon). This framework allowed a complete stratigraphical scheme of major vegetation events for the last 430 ka and facilitated differentiation of the palynological characteristics within MISs. ...
... MIS9 Pz12,Pz13) It must be highlighted that, following Tzedakis et al. (1997), we considered the isotopic event 8.5 was included within the MIS9 complex (event 8.5 corresponding to MIS9a), with the MIS9/8 boundary placed at ca. 280 ka, which will be useful for the correlation with other long European records. ...
... The location of these sites and the climatological region to which they belong are in Fig. 1. Of note, following Tzedakis et al. (1997), the isotopic event 8.5 was included within the MIS9 complex (event 8.5 corresponding to MIS9a), with MIS8 commencing at ca. 280 ka. The pollen records were plotted in age or depth according to their original published source, and the correlation was performed according to the description of environmental episodes and MIS found in the original papers some short phases of increasing aridity were also identified within these stages. ...
We provided valuable information about the palaeoenvironmental evolution of Southwestern Europe during the last 800 ka through the palynological study of the longest continuous continental Quaternary record in the Iberian Peninsula and in the Southwestern Mediterranean region. The SPD core studied here constituted the longest sequence recovered at the Padul Basin and we improved the chronological precision with respect to previous research. Furthermore, the high sampling resolution provided interesting insights into the main vegetation changes occurred at long-term timescales in the region and allowed correlating these variations with other long continental records of Europe. Dating using palaeomagnetism, amino acid racemisation, U/Th and 14C allowed us to construct a robust Bayesian age-depth function, thereby making it possible to determine the chronological framework for the Padul record. From the palynological content of the samples, which were grouped in 11 clusters, we obtained a large variable number of minor pollen variations totalling 21 palynozones identified along the record. From the statistical analysis of the pollen data, some pollen environmental indexes were defined, allowing the reconstruction of palaeotemperature and palaeohumidity conditions. Five climatic scenarios were established: cold/arid, cold/semi-arid, cold/wet, temperate/wet (Mediterranean-climate), and warm/wet (Mediterranean-climate with higher moisture). Of note, the vegetation in the Padul Basin differed from that of other European basins with long pollen records due to regional characteristics, but main palaeoenvironmental trends were in agreement. Pinus, Steppic, Xerophilous, and Mediterranean taxa in the Padul Basin showed a continuous and dominant presence along the whole record, while only in certain periods did humidity increase, reflected by the expansion of Spores, Deciduous and Mediterranean taxa (especially in Pz 2, 7 and 13), but without any large expansion of deciduous forest. Comparison with other European records revealed the singular bioclimatic position of the Padul Basin in the Southwestern Mediterranean realm, and this part of Iberia can be considered a Quaternary vegetation refuge, mainly for mesophillous taxa and sclerophyllous oak. Although the biomes of the Padul basin and other European basins could not be compared directly, the main palaeoenvironmental trends were coincident (interstadials were marked by warmer periods and greater humidity, whereas stadials were cooler and more arid). These observations suggest that environmental changes in the Padul Basin were in tune with variations in global palaeoclimatic conditions.
... Lisiecki and Raymo, 2005), regional variability exists and boundaries are transient both spatially and temporally (Fig. 3). Similarly terrestrial responses to climate change are often diachronous and/or asynchronous and therefore terrestrial and marine stage boundaries are not necessarily time parallel (Tzedakis et al., 1997;Shackleton et al., 2003;Past Interglacials Working Group of PAGES, 2016;Gibbard and Hughes, 2021). ...
The Balzi Rossi archaeological complex (comprised of caves, rock shelters, and open-air sites) is a globally significant site for Palaeolithic culture and understanding the transition from Neanderthal to Anatomically Modern Human populations in Europe. It also retains some of the earliest evidence of human interactions with their coastal environment. Balzi Rossi has been subject to excavation for over 150 years – traditionally as individual site locations – with most deposits removed when the discipline of archaeology was nascent, and the science not yet developed. The consequence was the unfortunate loss of materials and critically important stratigraphic context. However, valuable information regarding the Palaeolithic population, their coastal environment, and earlier sea-level change, remains in the literature and in museum repositories. In this work we have compiled and reviewed the extensive resources, available largely in French and Italian, to provide a summary and catalogue for each individual site. These ‘Site Summaries’ are available as appendices to this review, which provides a comprehensive synopsis of the history of excavations conducted at Balzi Rossi, a reconstruction of stratigraphy where possible, the evidence of Palaeolithic occupations, the evidence of Pleistocene sea-level fluctuations, and an assessment of the chronological constraint available for both the Palaeolithic populations and sea level. Finally, this synopsis identifies gaps in knowledge and provides comments on pathways for future research, suggesting a consilient approach that can be applied in other archaeological contexts.
... However, southern Europe has often been overlooked in range-wide genetic or genomic datasets, despite its disproportionate importance as a long-term repository of genetic diversity (Hampe and Petit 2005). Southern Europe has likely acted as a mosaic of small, favourable refugia for the persistence of tree species during the cold phases of the Quaternary (Bennett et al. 1991;Tzedakis et al. 1997), resulting in southern European populations often exhibiting complex patterns of genetic variation (Piotti et al. 2017;Scotti-Saintagne et al. 2021). Robust sampling within putative refugial areas is essential to quantitatively describe such complexity in the spatial structure of extant genetic variation (Piotti et al. 2017) and, thus, to plan more effective conservation strategies of forest genetic resources (Vries et al. 2015). ...
Knowledge of the spatial distribution of intraspecific genetic variation is essential for conserving biodiversity, designing rational networks of protected areas, and informing translocation strategies. Although the Italian peninsula likely harbours unique genetic variation as a legacy of Quaternary migrations towards southern Europe, few genetic data are available for many Italian forest tree species and populations.
Here, we present the first, comprehensive characterisation of the nuclear genetic variation of Italian populations of pedunculate oak (Quercus robur L.), an iconic broadleaved species of lowland forests. A total of 745 individuals from 25 populations were sampled across the local range of the species and genotyped with 16 microsatellite markers. The genetic layout of Q. robur populations was assessed through various metrics of diversity and distinctiveness, as well as by Bayesian clustering and multivariate methods. Based on the inferred genetic structure, the demographic history of Q. robur gene pools was evaluated through Approximate Bayesian Computation (ABC) analysis.
We found a clear spatial trend in the estimates of genetic diversity and distinctiveness of Italian Q. robur populations. The genetic distinctiveness and private allelic richness values showed a linear decline with increasing latitude, while allelic richness reached its peak in central Italy. We also observed a south-to-north trend in the complexity of genetic structure, with peninsular Italy being characterised by a mosaic of gene pools, in contrast to the homogeneity exhibited by northern Italian populations. Demographic inference indicated that the southern gene pool has had separate dynamics for the last 135,000 years and, therefore, populations in central Italy did not originate from a northward migration route after the Last Glacial Maximum (LGM). Therefore, they were not only a "melting pot" of multiple recolonization routes, but most likely a mosaic of small refugia where pedunculate oak persisted during the LGM.
Our results shed new light on conservation priorities for highly fragmented Q. robur populations, and call for consideration of whether treating the southern and central Italian populations as independent conservation units, or intervening to increase their genetic connectivity, is the best strategy for their long-term conservation.
... The study of pollen records from southern Europe has long been acknowledged as fundamental for the reconstruction of past terrestrial environmental changes, being the only quantitative proxy that provides continuous and accurate records of vegetation changes over the Quaternary glacial-interglacial cycles (e.g., [1][2][3][4]). There is consensus that the Quaternary vegetation dynamics of the north-eastern Mediterranean region were alternations between steppe/grassland and deciduous/evergreen forests occurring as a response to glacial-interglacial climatic cycles (e.g., [5][6][7][8][9]). ...
The Gulf of Corinth is a semi-isolated basin in central Greece interrupting the Pindus Mountain Range, which nowadays is a biodiversity hotspot. Considering its key location, deep drilling was carried out within the International Ocean Discovery Program (IODP; Expedition 381: Corinth Active Rift Development) aiming to improve our understanding of climatic and environmental evolution in the region. Here, we present a new long pollen record from a Mediterranean setting in the southernmost tip of the Balkan Peninsula recording the vegetation succession within the Quaternary. The Corinth pollen record shows no major shifts in arboreal pollen between glacial and interglacial intervals, while Mediterranean and mesophilous taxa remain abundant throughout the study interval. During interglacials, the most frequent reconstructed biomes are cool mixed evergreen needleleaf (CMIX) and deciduous broadleaf forests (DBWB), while graminoid with forb (GRAM) and xerophytic shrubs (XSHB) dominate within glacials. Our findings support the hypothesis that the study area was a significant refugium, providing suitable habitats for Mediterranean, mesophilous and montane trees during successive Quaternary climate cycles.
... Studies on deep sea sediments, continental deposits of flora, fauna and loess, and ice cores show that during the last one million years series of large glacial-interglacial changes occurred with cycles of about 100.000 years (see e.g. [38], [73]). This implies that climate in the past was not fixed. ...
... Studies on deep sea sediments, continental deposits of flora, fauna and loess, and ice cores show that during the last one million years series of large glacial-interglacial changes occurred with cycles of about 100.000 years (see e.g. [38], [73]). This implies that climate in the past was not fixed. ...
This Handbook analyzes the macroeconomics of global warming, especially the economics of possible preventative measures, various policy changes, and potential effects of climate change on developing and developed nations.
... These shifts caused cooling of the ocean surface water, with estimates by several authors as follows: a decrease of 4-6°C (Kaiser et al., 2005); a drop of 4.0 ± 0.8°C and temperatures of −4°C to −8°C at 60-45°S during the LGM (Annan and Hargreaves, 2013) and of 5-8°C near the continent (Hulton et al., 2002), where the mean annual temperature was ∼7-8°lower than at present (Benn and Clapperton, 2000). Tzedakis et al. (1997), however, showed that marine oxygen isotope records do not account correctly for variations on the continent. Kohfeld and Harrison (2001) considered that atmospheric models have underestimated the magnitude of cooling and drying of most of the land surface during the LGM. ...
Pleistocene permafrost has been recognized in the lowlands of extra-Andean Argentina from Tierra del Fuego to the Rio Negro valley at 40°S, and to the Sierras Australes at 38°S. Features that could have formed only by cryogenic activity at elevations between 230–400 m above sea level in surficial deposits and in the bedrock beneath are described here as far north as 36°S. These features are not as pronounced as they are farther south because most of central Argentina was a cold desert during the glacial episodes, and therefore little ice formed. Calcareous dust, formerly considered as pedogenic and now known to be glaciogenic, is closely associated with these features. Secondary precipitates, such as lamellar crystals of calcite and gypsum, and other microscopic features like those observed in perpetually frozen ground also confirm that this region experienced permafrost at some time. These new findings mean that the area affected by periglaciation is much larger than previously thought and expanded more than 200 km farther to the north. Stratigraphic evidence and geomorphological features place both deposits and cryogenic features within them as early–middle Pleistocene age.
... However, the interpretation of the climatic record fi-om deep-sea cores (Shackleton and Opdyke 1973) has had a major impact on the interpretations of both the dating and the environmental conditions of Europe. In combination with faunal remains, pollen and charcoal, broad environmental conditions can be suggested for successive stages in Middle Pleistocene Europe (Tzedakis et al. 1997). ...
p>The core argument demonstrates that the archaeological notion of transitions is untenable. They structure the past into blocks of time, thereby amalgamating behaviour patterns and establishing universal interpretations that are situated outside of hominid action. Within the current framework a transition is a historical junction point in chronological time, organised according to change and variation in archaeological assemblages. Several models have been proffered to explain change, but the underlying framework through which transitions are established has rarely been questioned, because of their key role in the interpretation of hominid evolution.
This traditional framework is critiques and two themes are addressed to re-contextualise Middle Pleistocene archaeological interpretation. Firstly, in an exploration of the concepts of temporality and the taskscape, it is argued that time and space are mutually produced through hominid action. This alters the interpretation of change and variation, which is my second theme. I conclude that they exist in unison, as change is a constant although inconsistent process of transformation.
Undermining the notion of fixed points of transition renders research focusing on origin points, and therefore modern humans origins, implausible. Current discourse on hominid identity draws on the structural opposition of 'modern' versus 'archaic' humans for interpretation. In contrast, I locate hominid identities through the exploration of social praxis , offering a way of linking recent social theory with the practice of lithic analysis to interpret changing hominid identities. The transformation from the Acheulean to the Middle Stone Age and Middle Palaeolithic is characterised in five case studies that analyse Middle Pleistocene lithic assemblages from the UK, France and South Africa. I demonstrate that there is no single identity for Acheulean, Middle Stone Age or Middle Palaeolithic hominids, and show how non-linear transformations in the detailed analysis of lithic artefacts and the surrounding taskscape can portray changing relations in hominid social life.</p
... Eastern North Atlantic deep-sea and European pollen records show that within interglacial periods a succession of maximum forest expansions alternated with forest contractions (Fig. 2e, The opposite is registered for the MIS 11 interglacial,~420 ka. During glacials the dominance of herbaceous vegetation was marked by the expansion of Mediterranean (dominated by Artemisia, Ephedra, and Amaranthaceae) and Centro-European (dominated by Poaceae, Cyperaceae and Artemisia) steppes and shrub-tundra in more northern regions (Helmens 2014;Sánchez Goñi et al. 1999;Tzedakis et al. 1997). So far, the best studied millennial-scale climate variability is that observed during the last glacial period (MIS 5d to MIS 2, i.e.~115-14.7 ka) characterised by a series of warming and cooling events called Dansgaard-Oeschger (D-O) cycles that were first identified in the atmosphere of Greenland and usually lasted 500-2,000 years (Dansgaard et al. 1984) (Fig. 3a). ...
The analysis of ancient pollen (and spores) preserved in sedimentary sequences is a classical approach used in paleoclimatology, paleoecology and archaeology since the beginning of the twentieth century. Yet, pollen analysis is the most powerful tool to reconstruct past vegetation changes affording more precise documentation of distribution, composition and land vegetation cover than geochemical tracers only providing the wet/dry-loving plants ratio through time. Ancient pollen from deep-sea cores has allowed the direct comparison of vegetation and atmospheric conditions on land with changes in ocean and ice sheet dynamics, identifying, for instance, a strong air-sea thermal contrast at orbital and millennial time scales in the European margin favouring moisture production and transport to northern hemisphere high latitudes and the last entering in glaciation. The study of ancient pollen along with plant macro remains and modern and ancient DNA has revealed the location of cryptic refugia for temperate and boreal trees during cold periods and reduced the original velocity estimations for tree migration highlighting the difficulty for certain trees to keep pace with the on-going climate change. Pollen-based vegetation changes are of most relevance to understand human evolution as past populations were tightly dependent on plant and animal resources. Repeated and strong savannah expansion in eastern Africa contemporaneous with the onset of large northern hemisphere glaciations provided enough animal resources that allowed hominin brain increase and the emergence of early Homo. In Europe, the successive and rapid steppe-dominated cold periods punctuating the last glacial period triggered repeated increases of ungulate biomass and human demography that may explain the increase and accumulation of innovations in Homo sapiens populations.KeywordsDeglaciationGlacial-interglacial climate changesGlaciationOrigin and evolution of Homo sapiensPast atmospheric CO2 concentrationRapid climate changesRefugium zones for trees
... In addition, during this period Neanderthals were replaced by modern humans (Bar-Yosef and Pilbeam 2000;Bradtmöller et al. 2012;Staubwasser et al. 2018;Greenbaum et al. 2019). The sequence and intensity of these climate variations have been documented through detailed pollen (Tzedakis 1994;Tzedakis et al. 1997Tzedakis et al. , 2003Tzedakis et al. , 2004Tzedakis et al. , 2006 and micropalaeontological studies (Geraga et al. 2005;Bludau et al. 2021) in Greece. Both methodologies have uncovered the alternation of warm and cold periods and subphases, characterised by respective expansions of forest and open environments, equally affecting the expansion and diversity of terrestrial animals. ...
The present study focuses on the microvertebrate fossil material retrieved from the three fossiliferous units of Kalamakia cave dating from ca. 90-25 kya BP, to identify the accumulation agents of the assemblage and the processes that affected it post-depositionally. This was done through the quantification of specific indices described in the literature concerning breakage, digestion and other types of modifications observed upon the surface of the specimens. Furthermore, the Taxonomic Habitat Index was calculated to reconstruct the possible habitat types in the surrounding area. Regarding the results on taphonomy, significant amounts of post-depositional breakage were observed, possibly resulting from trampling and, secondarily, modifications from the occasionally naturally occurring high humidity within a cave. The main accumulators of the microvertebrate assemblage seem to have been barn owls either independently or jointly with long-eared owls and/or owlets. Concerning the habitats possibly present in the area, the existence of mixed habitats varying between relative expansions of shrublands, grasslands, rocky areas and (limited) deciduous forests was identified, while the occasional presence of water bodies was also revealed. Shifts between the percentages of different habitats were not great but could be correlated with climatic events within a geochronological context. ARTICLE HISTORY
... Pollen analysis needed 2 decades, and the main results were published between 1979 and 1987. In the 1990s, the age-depth model of this core was improved and a land-sea correlation consequently developed (Tzedakis et al., 1997(Tzedakis et al., , 2001(Tzedakis et al., , 2006. Together with the long continental records from the Padul Basin, Spain (Florschütz et al., 1971;Pons and Reille, 1988;Torres et al., 2020), and the Grande Pile (Woillard, 1978), and Les Échets in France (de Beaulieu and Reille, 1984), to Clear Lake (Adam et al., 1981) and Tule Lake (Adam et al., 1989) in the USA, the continental drilling scene was set. ...
We sketch the initial history of collecting deep cores in terrestrial and marine sedimentary basins and ice cores to study environmental and climate change. Subsequently, we focus on the development of long records from the Northern Andes. The 586 m long pollen record from ancient Lake Bogotá reflects the last 2.25 × 106 years with ∼ 1.2 kyr resolution, whereas the sediment core reflects almost the complete Quaternary. The 58 m long composite core from Lake Fúquene covers the last 284 ka with ∼ 60 years resolution. We address the various challenges and limitations of working with deep continental cores. For the tropics, the presence of these deep cores has made the Northern Andes a key area in developing and testing hypotheses in the fields of ecology, paleobiogeography, and climate change. We summarize the results in the figures, and for details on the paleoenvironmental reconstructions, we refer to the corresponding literature. We provide an overview of the literature on long continental records from all continents (see the Supplement). Based on our 50 years of experience in continental core drilling, developing a research capacity to analyze the large amounts of samples, and keeping a team together to publish the results, we listed suggestions in support of deep continental records aimed at studying environmental and climate change over long intervals of time.
... The sensitivity of species and ecosystems to the transition from colder and generally drier climates of the LGM to the present is clear and unambiguous, with legacies that persist today, yet ecoclimate sensitivity remains poorly quantified. Micropaleontological time-series of community composition that span one or more glacial-interglacial cycles show large variations that match ice-core records of greenhouse gas composition and global ice volume, with this close coupling observed across terrestrial and marine records and across latitudes [100][101][102][103][104]. In middle and upper latitudes, thermophilous species contracted their ranges into glacial refugia, from which they expanded during post-glacial temperature rises [37,105,106] (Fig. 4A, B). ...
Two usages of ‘climate sensitivity’ co-exist: one climatological and one ecological. The earlier climatological usage quantifies the sensitivity of global mean surface temperature to atmospheric CO2, with formal variants differing by timescale and processes. The ecological usage, renamed here as ecoclimate sensitivity, is defined as a change in an ecological response variable per unit climate change. The two concepts are treated very differently: climatologists have focused on reducing uncertainty of global climate sensitivity estimates, while ecologists have focused on the multivariate processes governing variations in ecoclimate sensitivity across drivers, response variables, and scales. Because radiative forcing scales logarithmically to [CO2]atm, ecological impacts per ppm [CO2]atm often also scale logarithmically, although non-linear ecoclimate sensitivities can alter this expectation. Critically, past estimates of climate and ecoclimate sensitivity carry an implicit tradeoff, in which smaller estimates of climate sensitivity indicate higher ecoclimate sensitivities. For the LGM, estimates of equilibrium climate sensitivity have narrowed to 2.4 to 4.5 °C, while high ecoclimate sensitivity is indicated by post-glacial biome conversions, continental-scale species range shifts, and high community turnover. We introduce a new term, ecocarbon sensitivity, defined as the product of global climate sensitivity, local ecoclimate sensitivity, and a global-to-local climate scaling factor. Given past biospheric transformations, we can expect high sensitivity of the terrestrial biosphere to current rises in [CO2]atm, a conclusion that is insensitive to estimates of climate sensitivity. The next frontier is better quantification of the processes governing the form and variations of ecoclimate and ecocarbon sensitivity across systems and scales.
... The Quaternary has been characterized by cold glacial and warm interglacials periods paced by cyclical changes in Earth's orbital parameters (Tzedakis et al., 1997;Maslin, 2009). Of these periods, the Eemian (Last Interglacial, Marine Isotope Stage (MIS) 5e, ca 130e116 ka) is of special interest as it represents the most recent interval of widespread climatic warming in the geologic records with global mean temperatures of ca. ...
The Last Interglacial warm period, the Eemian (ca. 130e116 thousand years ago), serves as a reference for
projected future climate in a warmer world. However, there is a limited understanding of the seasonal
characteristics of interglacial climate dynamics, especially in high latitude regions. In this study, we aim
to provide new insights into seasonal trends in temperature and moisture source location, linked to shifts
in atmospheric circulation patterns, for northern Fennoscandia during the Eemian. Our study is based on
the distribution and stable hydrogen isotope composition (dD) of n-alkanes in a lake sediment sequence
from the Sokli paleolake in NE Finland, placed in a multi-proxy framework. The dD values of predominantly
macrophyte-derived mid-chain n-alkanes are interpreted to reflect lake water dD variability
influenced by winter precipitation dD (dDprec), ice cover duration and deuterium (D)-depleted meltwater.
The dD values of terrestrial plant-derived long-chain n-alkanes primarily reflect soil water dD variability
modulated by summer dDprec and by the evaporative enrichment of soil and leaf water. The dDprec
variability in our study area is mostly attributed to the temperature effect and the moisture source
location linked to the relative dominance between D-depleted continental and polar air masses and Denriched
North Atlantic air masses. The biomarker signal further corroborates earlier diatom-based
studies and pollen-inferred January and July temperature reconstructions from the same sediment
sequence. Three phases of climatic changes can be identified that generally follow the secular variations
in seasonal insolation: (i) an early warming trend succeeded by a period of strong seasonality (ii) a midoptimum
phase with gradually decreased seasonality and cooler summers, and (iii) a late climatic
instability with a cooling trend. Superimposed on this trend, two abrupt cooling events occur in the early
and late Eemian. The Sokli dD variability is generally in good agreement with other North Atlantic and
Siberian records, reflecting major changes in the atmospheric circulation patterns during the Eemian as a
response to orbital and oceanic forcings.
... The interglacial periods of the Pleistocene and Holocene have been widely studied since they represent those analogs (e.g. Kukla et al., 1997;Winograd et al., 1997;Tzedakis et al., 1997;Forsström, 2001;Kukla, 2005;Chen et al., 2008a). However, to date, most studies have focused on the Holocene and the last interglacial periods, which are broadly equivalent to Marine Isotope Stage (MIS) 5, while the documentation on the penultimate interglacial period that is equivalent to MIS 7 is relatively poor and mainly differed from the δ 18 O record of stalagmites (Turon, 1984;Kukla et al., 1997;Sanchez-Goni et al., 1999;Wang et al., 2001;Dykoski et al., 2005;Kukla, 2005;Kelly et al., 2006;Cheng et al., 2016). ...
The interglacial periods of the Pleistocene (MIS 5) and Holocene have been widely studied as analogs, whereas the records of the penultimate interglacial complex (MIS 7) are relatively sparse. In this study, based on a multitude of proxies, such as magnetic susceptibility, geochemical elements and their ratios, and grain size spanning MIS 7 of Xiashu Loess, the paleoclimatic changes that are synchronous with the five episodes during MIS 7 are reconstructed in the Chaohu Lake Basin, East China. It is proposed that the paleoclimate change in Chaohu Lake Basin during MIS 7, on orbital time scale, might be controlled by low-latitude insolation; on millennium scales, might be directly driven by the global ice volume variations.
... insolation values at high latitudes and is often found to dominate low-latitude and local climatic processes [Kutzbach, 1981;Bender et al., 1994;Tzedakis et al., 1997;Clemens and Prell, 2003;Ruddiman, 2003;Tzedakis et al., 2003;Wang et al., 2008;Yin and Berger, 2012;Collins et al., 2014;Govin et al., 2014]. Obliquity, on the other hand, is more influential in distributing insolation between low and high latitudes and can thus drive glacial processes when low obliquity reduces the magnitude of northern (as well as southern) summers in polar and subpolar regions [Vernekar, 1972;Berger, 1978;Ruddiman and McIntyre, 1984;Imbrie et al., 1992;Huybers, 2006] and more generally affects processes associated with annual mean insolation and its latitudinal gradient [Loutre et al., 2004]. ...
... However, depending on their ability to survive climatic and environmental changes, several of these taxa still occured during the Middle Pleistocene and persisted until the Holocene (Orain et al., 2013;Velitzelos et al., 2014;Combourieu-Nebout et al., 2015;Magri et al., 2017;Kousis et al., 2018;Margari et al., 2018;Sinopoli et al., 2018;Panagiotopoulos et al., 2020). (1) Tenaghi Philippon, (2) Valle di Castiglione, (3) Crotone (Tzedakis et al., 2006), B: Montalbano Ionico, South Italy (Dubois, 2001;Suc & Popescu, 2005in Rohais et al., 2007b, C: Zakynthos Island (Subally et al., 1999, D: Rhodes (Joannin, 2003;Joannin et al., 2007), E: Vouraikos Gilbert Delta , F: Caltagirone-Sicily (Dubois, 2001, G: Megalopolis (Okuda et al., 2002), H: Ioannina 249 (Tzedakis et al., 1997), I: Tenaghi Philippon, Valle di Castiglione (Tzedakis et al., 2001), J: Lake Ohrid (Bertini et al., 2016), K: DSDP 380-Anatolia (Biltekin et al., 2015). L: Southern Europe (Magri et al., 2017), M: Alleret (Degeai et al., 2013), N: Rhodes (Boyd, 2009), O: Cañizar de Villarquemado (Gonzalez-Samperiz et al., 2013), P: Aegean (Joannin et al., 2008, Q: Vallo di Diano (Ermolli et Cheddadi, 1997), R: Lagaccione (Magri et Sadori, 1999), S: Gulf of Corinth (Fouache et al., 2005) , T: Lamone Valley (Fusco, 2007). ...
Proximal alluvial sediments represent a useful sedimentary archive to reconstruct the tectono-climatic history of continental rift basins. However, poor dating of coarse fluvial successions usually prevents high-resolution distinction of tectonic and climatic processes, and thus good determination of process rates. This paper presents a dating study of Plio-Pleistocene Kalavryta river system during the early history of the Corinth Rift (northern Peloponnese, Greece) based on magnetostratigraphy and palynology. This river system developed across several active normal fault blocks that are now uplifted along the southern rift margin. The detailed sedimentary record constrains alluvial architectures from the proximal basin to the river outlet where small deltas built into a shallow lake. In four magnetostratigraphy sections the correlation to the reference scale relies on the identification of the Gauss/Matuyama magnetic reversal and biostratigraphic elements. The river system developed between about 3.6 to 1.8 Ma, with sediment accumulation rates (SARs) ranging from 0.40 to 0.75 mm yr⁻¹. SAR is lower in the alluvial fans than in the deltaic system, and higher at the centre of the normal fault depocentres than at the fault tip. By comparison with worldwide Cenozoic SARs, our values are higher but lie in the same range as those determined in coarse alluvial foreland basins. Moreover, in the context of overfilled intra-mountainous rift basins, these rates are minimum values and can be used as a proxy for accommodation rate. Therefore, early rift stratal wedges and growth synclines attest high sedimentation rates and also high rates of tectonic processes. Finally, in the distal river system, floral compositions and changes of vegetation deduced from palynological data are coherent with alternating fluvio-deltaic and shallow lacustrine deposits, which are linked to relative base level variations. Dry/cool climate is preferentially recorded during periods of low lake level, while the warm/moist climate is mainly recorded in prodelta deposits during periods of high lake level. This correlation suggests that, despite the dominant control of active faulting, climate is a key control of syn-rift stratigraphic architectures.
... The pollen records from Bogotá and Tenaghi Philippon were later extended to cover the last 2.2 Myr (Hooghiemstra 1984;Hooghiemstra et al., 1993;Torres et al., 2013) and 1.35 Myr (Wijmstra & Groenhart 1983;van der Wiel & Wijmstra 1987a,b;Tzedakis et al. 2006), respectively. Gradually, a number of long pollen sequences emerged from southern Europe, showing expansions and contractions of forest communities associated with variations in ice volume, although glacial-interglacial transitions in the marine and terrestrial records were not always synchronous (Tzedakis et al. 1997(Tzedakis et al. , 2004Shackleton et al. 2003). ...
James Croll's Physical Theory of Secular Changes of Climate emerged during an age of revolution in geology that included the rise of the glacial theory and the search for its underlying causes. According to Croll, periods of high eccentricity are associated with the persistence of long glacial epochs, within which glaciations occur in alternate hemispheres when winter is at aphelion every ~11,000 years; however, astronomical forcing is only able to produce glaciation by means of physical agencies (climate feedbacks) that amplify the small effects of varying seasonal irradiation. Croll understood the importance of interglacial deposits because they provided evidence for the occurrence of multiple glaciations within his long glacial epochs. He was aware of the limitations of the terrestrial record and suggested that deep-sea sediments would contain a continuous succession of glacial-interglacial cycles. Contrary to a widespread view, however, Croll was not envisaging the advent of palaeoceanographic exploration avant la lettre , but instead was drawing attention to the inadequacy of the land record as a testbed of his astronomical theory. Yet, the marine record did eventually deliver a test of astronomical theories almost exactly 100 years after the publication of his 1875 book Climate and Time in their Geological Relations . Here, we provide an historical account of the technological and scientific developments that led to this and a summary of insights on astronomically paced climate changes from marine, terrestrial and ice core records. We finally assess Croll's ideas in the context of our current understanding of the theory of ice ages.
... Below the MIS 7 proximal marine deposits, CB core shows a 3.77 m-thick basal unit constituted by alluvial sediments characterized by pollen assemblage dominated by pine (CB1 pollen zone). The attribution of this interval to the MIS 7d is excluded, as the pollen signature of the unique sample does not reflect neither the extremely dry and cold vegetation of the substage 7d, nor the substage 7e warm phase (Follieri et al., 1988;Reille et al., 1998;Tzedakis et al., 1997Tzedakis et al., , 2001Tzedakis et al., , 2003. A clear attribution to a specific marine isotopic stage is difficult as it would be based on a single sample. ...
The multidisciplinary analysis of two long sedimentary successions of continental and shallow marine deposits from the Venetian plain (NE Italy) provides new data on the stratigraphic architecture and the landscape evolution of the south-eastern Alpine foreland basin during the last 210–220 ka, with further evidences of a warm temperate phase older than MIS 8.
We present and discuss a detailed multi-proxy data set from these successions (GER1 and CB cores). The results of stratigraphic, palynological and micropalaeontological analyses are cross-interpreted, showing the potentiality of building a composite section of two close continental successions within the same alluvial system, the Brenta megafan, with 15 km distance between cores along a downstream direction. The chronology of the upper part of the cores is supported by radiocarbon dating, showing the presence of Last Glacial Maximum (LGM) and post-LGM fluvial deposits. Lower down, the estimated chronology relies on the tight integration between palynostratigraphy and lithostratigraphy, on the recognition of main unconformities, as well as on the correlation with other regional biostratigraphic records and the Northern Hemisphere/global isotopic record.
The only marine transgression recorded in the studied successions is attributed to the MIS 7.3 and represents the basal tiepoint for the correlation between the two cores. Below the MIS 7.3 transgressive marine surface there is a fluvial succession with weakly-developed palaeosoils and a poor pollen content suggesting cold climate (possibly MIS 8), that lies on top of a thick peat layer showing palynological evidence of a warm temperate climate. The occurrence of well-preserved Pterocarya and Carya pollen in the basal peat level (GER1 core) is compared to that of other pollen sequences in Europe, providing new insights for the chronological framing of the problematic last occurrence of these taxa in the southern alpine area.
Whilst mixed temperate forest persisted throughout MIS 7c-7a, conifers spread during MIS 6. By this time, a glaciofluvial aggradation phase is recorded, highlighting the strong relationship between glacial maxima and alluvial aggradation in the Venetian plain. None of the drilling sites were reached by the Last Interglacial sea transgression. However, the Eemian forest signature is well recorded in CB core, and the following Early to Middle Würm stadial-interstadial sequence is clearly outlined thanks to the joint analysis of the two successions. Broad-leaved thermophilous forests disappeared at the end of the Early Würm and only Pinus and Betula persisted throughout the LGM, during which a chronologically well-constrained glaciofluvial aggradation occurred. The last depositional event corresponds to the post-LGM cut-and-fill of fluvial incised valleys in GER1 core, and to soil evolution and very thin burial by Brenta River fluvial deposits in CB core. The comparison between the results of this study with data of previous deep cores in the distal alluvial plain remarks an increasing long-term subsidence towards Venice area.
... This supposes that the principle of uniformity, that is, where the present is the key to the past, applies. This is generally the case for data from the Quaternary, and in particular for continuous sequences that have been correlated over 500 000 years (Tzedakis et al. 1997). To verify this assumption, pollen samples are taken from modern or recent moss and their pollen spectra are compared with current vegetation. ...
Pollen grains emitted by terrestrial plants are used as indicators of past vegetation and climate. They have a very resistant envelop which protects them from oxidation. The morphology of their envelop is a characteristic of the emitting plant type. Every year, terrestrial vegetation disperses billions of pollen grains which accumulate everywhere and, in places where the catchment is humid, such lakes and bogs, they are preserved for long periods of time up to several hundreds of millennia. Then, by sampling the sediments and by counting the pollen grains by plant type, it is possible to reconstruct past vegetation and to statistically deduce climate variations which have induced the vegetation changes.
... This means that the best potential for long continuous Quaternary sequences occurs in tectonically active regions of the middle and low latitudes. For example, some of the longest terrestrial sequences are found in southern Europe and the Mediterranean region (Tzedakis et al. 1997;Turner 1998), Japan (Tarasov et al. 2011), the Andean tropics of South America (Hooghiemstra 1989;Torres et al. 2005;Felde et al. 2016) and the rift valleys of Africa (Lamb et al. 2018). Long sediment sequences are also present in tectonic basins unaffected by glaciation at higher latitudes but these are often restricted to continental interiors where Pleistocene glaciations were relatively limited because of limited moisture supply, such as the Lake Baikal in Siberia, Russia (BDP-99 Baikal Drilling Project Members 2005). ...
Initially, terrestrial evidence formed the foundation for the division of Quaternary time. However, since the 1970s there has been an abandonment of the terrestrial stage chronostratigraphy, which is based on locally-dominated successions, in favour of the marine oxygen isotope stratigraphy which largely records global-scale changes in ice volume. However, it is now clear that glacial records around the world are asynchronous, even at the scale of the continental ice sheets which display marked contrasts in extent and timing in different glacial cycles. Consequently, the marine isotope record does not reflect global patterns of glaciation, nor other terrestrial processes, on land. This has led to inappropriate correlation of terrestrial records with the marine isotopic record. The low resolution of the latter has led to a preferential shift towards high-resolution ice-core records for global correlation. However, even in the short-term, most terrestrial records display spatial variation in response to global climate fluctuations, and changes recorded on land are often diachronous, asynchronous or both, leading to difficulties in global correlation. Thus, whilst the marine and the ice-core records are very useful in providing global frameworks through time, it must be recognised that there exist significant problems and challenges for terrestrial correlation.
... En effet, en appliquant un principe à l'évolution du climat dans une région donnée sur des séquences continues de plus de 500.000 ans (Cheddadi et al., 1996;Tzedakis et al., 1997;Rousseau et al., 2006;Guiot et al, 2009;Brewer et al., 2017). ...
La calibration du paléo-thermomètre Li/Mg a ici été revisitée pour 15 espèces de corail mises en culture ou issues de contextes environnementaux variés, allant des régions tropicales aux eaux profondes Antarctiques. Ces travaux de thèse ont montré que ce nouveau proxy retrace bien toute la gamme de température de l’océan allant de -1 à 29°C, avec une précision de l’ordre de± 1,0°C. Cependant, la présence dans le squelette de matière organique ou de calcite diagénétique peut biaiser les températures reconstruites. Il a également été montré que ces effets peuvent être corrigés par un nettoyage chimique adapté ou par des analyses spécifiques à micro-échelle. Une analyse des données Li/Mg dans les coraux tropicaux indique que les incertitudes de reconstruction sont plus élevées pour les eaux de surface chaudes et soumises aux variations saisonnières des facteurs environnementaux (SST, lumière, précipitations, etc.). Les processus de calcification ou le mode de croissance de ces espèces à zooxanthelles, contrôlés par leur localisation (lagon) et par les variations saisonnières, semblent altérer la précision du traceur Li/Mg. Toutefois, en combinant les rapports élémentaires Li/Mg et Sr/Ca dans une approche multi-proxy, ces incertitudes peuvent être considérablement réduites, de l’ordre de ± 0,6°C. En première application et après analyse de calibrations globales ou locales, l’évolution historique des températures a été retracée à partir d’une colonie de Siderastrea siderea prélevée vivante en Martinique. La série temporelle obtenue couvrant les 2 derniers siècles trace clairement le réchauffement climatique en cours dans la région des Caraïbes, en accord avec les données existantes. Une seconde application concerne l’utilisation du Li/Mg dans des coraux profonds fossiles de la Mer Méditerranée et permet de reconstruire l’évolution des températures depuis 55 000 ans des eaux intermédiaires de la Méditerranée, tracées particulièrement froides au LGM, et cela en réponse au dernier cycle glaciaire/interlgaciaire.
... In southern Europe, the 100-kyr cycles are marked by the alternation of interglacial temperate forest and glacial open vegetation as shown by the Tenaghi Philippon and the IODP site U1385 pollen sequences but also in other southern European pollen sequences covering several climatic cycles such as Ioannina and Kopais in Greece (Okuda et al., 2001;Tzedakis, 1993;Tzedakis et al., 1997Tzedakis et al., , 2006, Praclaux in France (de Beaulieu et al., 2001;Reille et al., 2000), Lake Ohrid in Albania , Valle di Castiglione in Italy (Follieri et al., 1988) and cores MD99-2331/MD03-2697/MD01-2447 from the NW Iberian margin and MD95-2042/MD01-2443 from the SW Iberian margin (e.g. Desprat et al., 2017;Sánchez Goñi et al., 2018). ...
... A drawback of this approach is that correlative interpretations are dependent on the accuracy of both the correlations between sites and the chronology to which records are tuned, subsequently producing tentative age models (Gasse and Van Campo, 2001;Chase, 2010). Orbitally tuned isotopic proxy data from terrestrial records, particularly wetland records, may also partly reflect local climate, and therefore may not directly parallel the Milankovitch cycle signatures typically observed in marine records (Tzedakis et al., 1997). Misidentification of isotopic peaks also remains a possibility in non-continuous terrestrial sedimentary sequences, and may introduce errors in the timing of proxy changes or incorrect attribution of purely localised isotopic signals to astronomical cycles (Malinverno et al., 2010). ...
Terrestrial sedimentary archives that record environmental responses to climate over the last glacial cycle are underrepresented in subtropical Australia. Limited spatial and temporal palaeoenvironmental record coverage across large parts of eastern Australia contribute to uncertainty regarding the relationship between long-term climate change and palaeoecological turnover; including the extinction of Australian megafauna during the late Pleistocene. This study presents a new, high-resolution, calibrated geochemical record and numerical dating framework from Welsby Lagoon, a wetland from North Stradbroke Island that records key periods of late Pleistocene environmental change. Single-grain optically stimulated luminescence and radiocarbon dating are integrated into a Bayesian age-depth model for the sedimentary sequence spanning Marine Isotope Stage (MIS) 5 to the present. Scanning micro X-ray fluorescence (XRF) and bulk sediment XRF assays are used to infer past dust dynamics, with changes in the abundance of silica and potassium interpreted as proxies for aridity across local and regional sources. Variations in dust flux were contemporaneous with hydrological change, concordant with changes in vegetation cover on the island and, relate to deflation events at major dust source regions on the Australian continent. The Welsby Lagoon record supports the notion of a variable MIS4 within which an increased dust flux (71–67 ka), may be indicative of drier climate. Additionally, the record also shows a lower dust flux through the Last Glacial Maximum (LGM) than is evident in other Australian aeolian records. However, this low LGM flux is attributed to the wetland’s evolution, rather than a reduction in total dust flux.
... A range of evidence for the nature of the environment and climate during the MIS 9 interglacial is now available from Purfleet and the other lower Thames sites attributed to this littleknown interval, some of it presented here for the first time. Whereas the earlier MIS 11 interglacial (more intensively studied because of its potential as a Holocene analogue) was relatively lengthy, although perhaps subdued in terms of maximum temperatures and certainly wetter than subsequent interglacials (Droxler et al., 2003;Kukla, 2003;Desprat et al., 2005;Preece et al., 2007), the fully temperate phase of MIS 9 (substage 9e) can be shown to have been relatively brief (Petit et al., 1999;Siddall et al., 2003;EPICA Community Members, 2004;Tzedakis et al., 1997Tzedakis et al., , 2004Tzedakis et al., , 2009Fig. 31). ...
... Immigration events, interspecific competition, and varying climatic constraints influenced the taxonomic composition of montane forest throughout the Pleistocene (Torres et al., 2013, Figure 10; Supplementary Information S2). In Europe, subsequent Pleistocene interglacial periods caused substantial loss of species and are the driving force behind taxonomic differences between the multiple interglacials (Tzedakis et al., 1997(Tzedakis et al., , 2001. Interestingly, the floral composition of montane forest in the northern Andes has been remarkably stable during the ten interglacials of the last 1 Ma (Felde et al., 2016). ...
We provide an overview of environmental and climatic change in Colombia during the Quaternary, the last ca. 2.58 million years (Ma) before present. This period is characterised by a suite of glacial-interglacial cycles which are remarkably well documented in Colombian sediments. The distribution of Colombia's main ecosystems has changed repeatedly driven by orbital forcing at 21, 41, and 100 ky frequencies which were superimposed by millennial-scale (ca. 2.5 ky) climate oscillations. Fossil pollen records have detected biome dynamics through time but records vary in length: the shortest comes from the Chocó rainforest (extending back to ca. 7 thousand years before present, ka) and dry inter-Andean forest (ca. 12 ka), followed by the savannas of the Llanos Orientales (ca. 20 ka), the Amazonian rainforests (ca. 40 ka), and lower montane forest (ca. 40 ka). The longest records are from the deep sedimentary basins Bogotá (Funza09, last 2.25 Ma) and Fúquene (last 284 ka), alternatingly located in the upper montane forest and páramo during interglacial and glacial conditions, respectively. Climate change caused shifting biome distributions: mainly latitudinally in the lowlands and elevationally in the mountains. Extrinsic drivers (e.g., mean annual precipitation , length of dry season, atmospheric pCO 2 , mean annual temperature, freezing days) of migration and changes in vegetation composition and intrinsic drivers (such as interspecies competition and legacy effects) are still insufficiently understood, and thus hamper meaningful projections of the effect of future environmental change on biomes. Multi-site Pleistocene and Holocene information has been spatially synthe-sised by developing the Latin American Pollen Database. Multi-site information has been analysed by the biomisation method to serve palaeodata-model comparisons and projections about the future of biomes in Colombia. A new method in which pollen based palaeo-reconstructions are spatially analysed with digital elevation models improved our understanding of spatial and elevational shifts of ecotones, for example the upper forest line, in the northern Andes. In the supplementary information we highlight the strengths and weaknesses in current Quaternary palaeoecological research and provide suggestions for future research. Resumen Presentamos una visión general del cambio ambiental y climático en Colom-bia durante el Cuaternario, últimos ca. 2,58 millones de años antes del presente (2,58 Ma). Este período se caracteriza por un conjunto de ciclos glaciales e interglaciales que se encuentran bien registrados en los sedimentos colombianos. La distribución de los Quaternary CHAPTER IN PRESS 2 HOOGHIEMSTRA et al. CHAPTER IN PRESS principales ecosistemas de Colombia ha cambiado repetidamente debido al forzamiento orbital a frecuencias de 21 000, 41 000 y 100 000 años que fueron superpuestas por os-cilaciones climáticas a escala milenaria (ca. 2500 años). Los registros de polen fósil han detectado la dinámica del bioma a través del tiempo; sin embargo, estos registros varían en duración: los registros más cortos provienen de la selva húmeda tropical del Chocó (ex-tendiéndose hasta ca. 7000 años antes del presente, ka) y del bosque seco interandino (ca. 12 ka), seguidos por las sabanas de los Llanos Orientales (ca. 20 ka), las selvas tropicales amazónicas (ca. 40 ka) y los bosques montanos bajos (ca. 40 ka). Los registros más largos corresponden a las cuencas sedimentarias profundas Bogotá (Funza09, últimos 2,25 Ma) y Fúquene (últimos 284 ka), ubicadas alternativamente en el bosque montano superior y el páramo durante las condiciones interglaciares y glaciales, respectivamente. El cambio climático provocó cambios en la distribución de los biomas: sobre todo latitudinalmente en las tierras bajas y altitudinalmente en las montañas. Los factores extrínsecos de la migra-ción (p. ej. la precipitación media anual, la duración de la estación seca, la pCO 2 atmosféri-ca, la temperatura media anual y los días de congelación) y los cambios en la composición de la vegetación y los factores intrínsecos (entre ellos la competencia interespecie y los efectos heredados) no son lo suficientemente comprendidos y, por lo tanto, dificultan las proyecciones del efecto de los cambios ambientales futuros en los biomas. La información pleistocena y holocena de múltiples sitios se ha sintetizado espacialmente mediante el desarrollo de la base de datos palinológicos de América Latina. La información palinológica de múltiples sitios se ha analizado mediante el método de biomización para contribuir a los modelos basados en datos paleontológicos y proyecciones sobre el futuro de los biomas en Colombia. Un nuevo método en el que las paleoreconstrucciones basadas en datos palinológicos se analizan espacialmente con modelos digitales de elevación mejoró nuestro entendimiento sobre los cambios espaciales y altitudinales de los ecotonos, por ejemplo, la línea forestal superior en los Andes del norte. En el material suplementario de este capítulo destacamos las fortalezas y debilidades en la investigación paleoecológica cuaternaria y ofrecemos sugerencias para futuras investigaciones. Palabras clave: cambio climático, Colombia, cambio ambiental, registros palinológicos, análisis cuantitativos, ambientes cuaternarios sin análogo.
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... 132-130 ka (Shackleton et al., 2002;Lisiecki and Raymo, 2005), although it has largely been a matter of debate (see literature review in Helmens, 2014;Martrat et al., 2014;Sier et al., 2015). Similarly, the environmental responses were not synchronous over the European continent (i.e., Woillard and Mook, 1982;Guiot et al., 1989;Tzedakis et al., 1997Tzedakis et al., , 2003Kukla et al., 1997;Allen and Huntley, 2009). ...
We present a multidisciplinary dating approach - including radiocarbon, Uranium/Thorium series (U/Th), paleomagnetism, single-grain optically stimulated luminescence (OSL), polymineral fine-grain infrared stimulated luminescence (IRSL) and tephrochronology - used for the development of an age model for the Cañizar de Villarquemado sequence (VIL) for the last ca. 135 ka. We describe the protocols used for each technique and discuss the positive and negative results, as well as their implications for interpreting the VIL sequence and for dating similar terrestrial records. In spite of the negative results of some techniques, particularly due to the absence of adequate sample material or insufficient analytical precision, the multi-technique strategy employed here is essential to maximize the chances of obtaining robust age models in terrestrial sequences. The final Bayesian age model for VIL sequence includes 16 AMS ¹⁴C ages, 9 single-grain quartz OSL ages and 5 previously published polymineral fine-grain IRSL ages, and the accuracy and resolution of the model are improved by incorporating information related to changes in accumulation rate, as revealed by detailed sedimentological analyses. The main paleohydrological and vegetation changes in the sequence are coherent with global Marine Isotope Stage (MIS) 6 to 1 transitions since the penultimate Termination, although some regional idiosyncrasies are evident, such as higher moisture variability than expected, an abrupt inception of the last glacial cycle and a resilient response of vegetation in Mediterranean continental Iberia in both Terminations.
... The Balkans have served as a bridge for the movements of species that had been restricted to Anatolia during Pleistocene glaciations [12] because the Balkan region of Europe and Anatolia were connected by a land bridge during the last glaciation [13,14]. In this relation, some authors [15,16] proposed that the modern genetic structure of S. scrofa in Europe is the result of a post-glacial colonization from one or more southern refugia, including Iberia and the Balkans but excluding the Italian Peninsula where a highly divergent mitochondrial DNA (mtDNA) exists. ...
The East Balkan Swine (EBS) is the only preserved local swine breed in Bulgaria and one of the few indigenous pig breeds in Europe. The EBS is distributed in the region of Eastern Balkan Mountains and the Strandja Mountain. To reveal the breed’s genetic profile, we analyzed 50 purebred individuals according to mitochondrial DNA (D-loop region, HVR1) and sequence analysis in the Scientific Center of Agriculture (Sredets region) in the country.
The obtained results show the presence of four haplotypes: three Asian specific haplotypes (H1, H2, and H3) and the European specific E1a1. The haplotypes H2 (6 %) and H3 (2 %) were newly described and were branched from the basic clade H1 (90 %). All haplotypes belong to the Asiatic clade A (98 %), except one sample assigned to the European haplogroup E1 (2 %) in contrast to samples from East North Bulgaria where Asiatic and Europen clades were with almost equal distribution. The coexistence of two mtDNA clades in EBS in Bulgaria may be related to the source of the pig populations and/or the historical crossbreeding with imported pigs.
In conclusion, due to its native origin, the East Balkan Swine may be the only possible option for a solution to the exhaustion of the beneficial genetic variation of available cultural breeds. With its participation, high-productive populations can be restored and established after a long and purposeful selection.
... Until relatively recently, interglacial deposits following this major glacial stage have been assigned to one of two temperate stages, namely the Holsteinian/Hoxnian or the Eemian/Ipswichian. It is clear from a consideration of not only the marine oxygen-isotope record (Shackleton & Opdyke, 1973) but also palynological records from long lacustrine sequences (Tzedakis et al., 1997) that the situation is more complex than this, and that at least four interglacials preceding the Holocene have occurred since the Elsterian/Anglian. These have been assigned to oxygen-isotopes stages 11, 9, 7 and substage 5e respectively, although these correlations -except for the last interglacial (5e) -are inferred rather than firmly established (cf. ...
Shells belonging to the bivalve genus Corbicula occur commonly in Pleistocene interglacial deposits in NW Europe. These have usually been identified as C. fluminalis , a modern species described from the Euphrates river, although the veracity of this specific attribution remains equivocal. Corbicula has nowadays a southern distribution, and laboratory studies indicate that it is thermophilous. It is also tolerant of brackish water, one of several attributes that make this an effective colonizer.
In NW Europe, Corbicula is known from the Lower Pleistocene but is absent from the Cromerian Complex, occuring again in the three interglacials following the Anglian/Elsterian. It appears to be unknown from the last interglacial, except as derived fossils.
... Hence, these taxa migrate southward during cold intervals and re-immigrate when the climate gets warmer and more favorable again (Müller et al., 2003). Because periglacial processes eroded broad regions in Central and northern Europe, paleorecords are rare north of the Alps (Behre, 1989;Tzedakis et al., 1997). The Füramoos sample site is therefore special, as it provides a continuous pollen record since the Eemian. ...
To contribute to the understanding of abrupt climate changes during the last glacial pe- riod of the Pleistocene, European vegetation dynamics in the northern alpine foreland were investigated. For this purpose a new pollen record from Füramoos, southwestern Germany, was developed with a mean temporal resolution of around 1 kyrs. Measurements of X-ray fluorescence (XRF) (temporal resolution <50 yrs), total organic carbon (TOC) and total in- organic carbon (TIC) (temporal resolution ca. 300 yrs, respectively) were applied to obtain supporting proxy data. The work of this thesis is based on two new drilled sediment cores spanning from 93 ka to 44 ka, representing a part of the Füramoos archive that covers the late Quaternary (Eemian to Holocene). Pollen-, XRF- and TOC-data reveal oscillating veg- etation changes between forest dominated warm interstadials and steppe/tundra dominated cool stadials. Overall, five interstadials (Brörup 3, Odderade, Dürnten, Bellamont 1 and Bella- mont 2) and four stadials (Würm Stadials B to E) are documented in the studied record. The palynostratigraphy of this record corresponds to the Marine Isotope Stages (MIS) 5c to 3.
The millennial-scale climatic oscillations observed at Füramoos are compared with δ18O- data from NGRIP ice cores and correlated with the Dansgaard-Oeschger events 12, 14, 19, 20, 21 and 22. Further comparison with pollen records from the Mediterranean region and sea-surface-temperature records from the North Atlantic reveals a similar pattern of climate change in all records that were taken into account. This suggests a supra-regional cou- pling between these sites through changes in the Atlantic meridional overturning circulation (AMOC) and through latitudinal shifts of atmospheric circulation patterns in Central Europe and the Mediterranean region.
The interglacial known as MIS 11c ( c. 426 000–396 000 years ago) receives intensive international interest because of its perceived role as an analogue for the current interglacial and its importance for understanding future climate change. Here we review the current understanding of the stratigraphy of this interglacial in Europe. This study considers (i) the evidence for the environmental history of this interglacial as reconstructed from the varved lake records from northern Europe, (ii) the climate history of MIS 11c as preserved in the long pollen records of southern Europe and (iii) a comparison of both of these with marine records from the North Atlantic. The result of this review is a discussion of the evidence for millennial and centennial scale climate change found in European records of MIS 11c, the patterns of warming that are seen across this interglacial and the discrepancy in aspects of the duration of this interglacial that seems to exist between the marine and terrestrial records of this warm period. A review of the recent advances in the study of MIS 11c in Europe confirms its importance for understanding both the past evolution of the Holocene and the future patterns of long‐term climate change.
Research subject. Bottom sediments of Lake Bannoe (Southern Urals). Aim. Identification of lithologic features of Lake Bannoe sediments, which could reflect sedimentation conditions in the Holocene. Materials and methods. The detailed complex analysis included radiocarbon dating, grain-size analysis, X-ray diffraction analysis, electron microscopy, X-ray fluorescence and isotope analysis, coercive spectrometry and pollen analysis. Results. Radiocarbon dating showed that sedimentation in Lake Bannoe began no later than ~13 thousand years ago. Combination of data from various laboratory studies unraveled four lithological zones and the corresponding stages in the sedimentation history. The grain size, allothigenic particles, carbonate minerals, organic matter and isotopic composition of carbon and oxygen are the most informative indicators. Grain size variations and the ratio between allothigenic and carbonate components reflect changes in the Lake’s depth and clastic material supply, which, in turn, is associated with humidity. Organic matter parameters (TOC, δ13Corg, C/N ratio) can be considered as indicators of climate-sensitive changes in bioproductivity of the sedimentation basin. They also reflect the ratio of exogenous and endogenous organic matter in the sedimentary environment. The isotopic composition of carbon and oxygen (δ13Ccarb, δ18Ocarb) in sedimentary carbonates is an informative indicator of lithological zones and climatic events of the Holocene due to its sensitivity to changes in biomass, temperature fluctuations, and fresh water inflow. The paramagnetic component k_para was used as an indicator of the allothigenic material input into the lake basin for the first time in this region. Conclusions. The granulometric, mineral, and chemical composition, as well as the magnetic properties of Lake Bannoe sediments reflect the history of Lake sedimentation in the Southern Urals, which agrees mainly with the climate stages of the Holocene.
This work presents the Middle Pleistocene palaeoenvironmental and archaeological record of the Valle Giumentina basin (Abruzzo, Italy). A high-resolution geological study, including stratigraphy, sedimentology and micromorphology, was performed on the lower part of the sequence which correlates with the time span between MIS 15 and MIS 14 stages, i.e. between 570 and 530 ka. In addition to long-term climatic variability, sedimentological data highlight many short oscillations of varying amplitude during both Glacial and Interglacial periods. These results are confirmed by the studies of environmental proxies (pollen and molluscan analysis) previously undertaken on the Valle Giumentina sequence in 2016. Comparisons with global, Mediterranean and Italian climate archives confirm the consistency of the Valle Giumentina record and the contrasting characteristics of each isotopic stages. The three archaeological levels comprised in this part of the sequence can be assigned to isotopic sub-stages MIS 15a (Level AO1-20), MIS 14d (Level 24) and MIS 14c/14b (Level LBr). Human groups lived here during both temperate and cold periods, into woodland and steppe landscapes. Petrographic, traceological and technological studies were undertaken on the small lithic series (total of 119 artefacts). They suggest that raw material procurement was strictly local. The core and flake production is of techno-type C (recurrent unipolar flaking, SSDA, flaked flakes). Several morphologies of blanks occur with regular and mostly straight cutting-edges (small and thin flakes, notches, thick backed flakes). They are rarely retouched. Despite their good state of preservation, the pieces do not exhibit use-wear traces.
Recent investigations into Marine Isotope Stage (MIS) 11 (424–403 ka), an unusually long and warm interglacial of the Quaternary Period, have found that the Atlantic Meridional Overturning Circulation remained strong while background melting of the Greenland Ice-Sheet (GIS) was high, and resulted in a fresh and cold surface ocean in the Nordic Seas. These investigations support the hypothesis that deep-water formation may not be as susceptible to future GIS melting as previously thought. Here we test this hypothesis and present a palaeoceanographic investigation of a freshwater-related abrupt climate event recorded in the eastern North Atlantic during peak interglacial conditions (~412 ka), when the GIS was as small or smaller than today. Using sediment core DSDP-610B recovered from the western Rockall Trough we reconstruct the evolution of Nordic Seas Deep-Water (NSDW) using benthic carbon isotope, Neodymium isotopes, and grain-size analysis paired with end-member modelling. Further, a combination of planktonic foraminiferal assemblage census and Ice-Rafted Debris counts allow us to reconstruct surface water properties including temperature and the movement of oceanic fronts throughout this event. Our results demonstrate that a reduction of NSDW only occurs once GIS melt and polar freshwater reaches subpolar latitudes. We hypothesise that the reorganisation of fresh and cold surface waters from the Nordic Seas into the subpolar North Atlantic was responsible for an AMOC-related cold event centred at 412 ka. Placing our results in the palaeogeographical context of the North Atlantic Region we tentatively propose that the ocean-atmosphere climate dynamics linking the Nordic Seas with the subpolar North Atlantic played and will play a crucial role for the stability of NSDW formation in the future, considering the enhanced melting and overall hydrological cycle at high Northern latitudes predicted for future climate scenarios.
Mountain regions have long been important for maintaining populations and genetic diversity of wild species, especially
those species that require large areas to sustain viable populations. We examined wolves (Canis lupus) in the Caucasus,
Carpathian, and Dinaric–Balkan regions, expecting these persistent populations to contain high genetic diversity and an
overlap of the major haplogroups detected in earlier broad-scale investigations. We analyzed 926 mitochondrial DNA control
region sequences, including 533 new samples whose geographic distribution allowed us to reduce sampling gaps observed
in previous broad-scale studies. We estimated genetic variability, population structure, and phylogeographic relationships
to evaluate the diversity and connectivity of populations throughout the study regions.
We detected haplogroups H1 and H2 that overlapped across the study regions. Haplogroup H1 can be divided into three sub-
groups: H1A and H1B that partially overlap throughout the study regions, and H1C that was found only in wolves from Arme-
nia. Haplogroup H2 was largely confined to the Carpathian and Dinaric–Balkan regions. Our analyses of population structure
partly concurred with the haplogroup distribution and produced four major genetic clusters. Our results demonstrated high
genetic diversity within the study regions, supporting their role in maintaining intraspecific variability in wolves and other
species that require large areas to sustain viable populations. The unique diversity and north–south structure observed within
the Caucasus emphasize the need for further research and conservation efforts in this highly biodiverse region. Our find-
ings highlight the role of broad-scale planning in conserving evolutionary processes in this and other transboundary areas.
The transition from the Marine Isotope Stage (MIS) 12 glacial (ca. 478–424 ka BP) to the MIS 11 interglacial (ca. 424–365 ka BP) is one of the most remarkable climatic shifts of the Middle Pleistocene and is regarded as a phase of major behavioural innovation for hominins. However, many of the available pollen records for this period are of low resolution or fragmented, limiting our understanding of millennial-scale climatic variability. We present a high-temporal resolution pollen record that encompasses the period between MIS 12 and MIS 10 (434–356 ka BP), recovered from the Ocean Drilling Program (ODP) Site 976 in the Alboran Sea. This study aims to provide new insights into the response of vegetation during the transition and to highlight patterns of climatic variability during MIS 11.
The ODP Site 976 pollen record shows the shift from glacial to interglacial at 426 ka BP, highlighted by the transition from Pinus, herbaceous and steppic taxa to temperate and Mediterranean taxa. A climatic optimum for temperate and Mediterranean taxa is identified around 426–400 ka BP, equivalent to substage MIS 11c and synchronous with the maxima in SSTs, greenhouse gas concentrations and insolation. A phase with increased Pinus and Cedrus indicates the return to colder and more arid conditions during substage MIS 11b (400–390 ka BP). Substage MIS 11a (390–367 ka BP) is marked by a period of short-term warming followed by gradual cooling, until the return of glacial conditions during MIS 10. Forest contractions have been linked with high- and moderate-intensity climate events also observed in other pollen records and proxies from the Mediterranean and North Atlantic.
Our results confirm the intense shift during the MIS 12/11 transition and show that this region is sensitive to millennial-scale climatic variation during MIS 11. The forest contractions observed in our record during events of millennial-scale variability appear to be less intense than in the central and eastern Mediterranean. This suggests that the southwestern Mediterranean may have been less variable during periods of climatic deterioration, thereby representing a possible ecological niche for vegetation. This may have provided a source of subsistence for hominins during harsher conditions, thus contributing to their demographic expansion and technological innovations.
Human dispersals and adaptations are the result of the dynamic relationship between cultural and biological systems. This chapter focuses on the last half a million years with an emphasis on the environmental controls on human dispersal and adaptation, with the perspective of spatiotemporal variations in environments as a key factor. It provides a brief overview of landscapes and their complexity and controls over time and space. Human dispersals and adaptations require an understanding of complex interactions and strong couplings that link human dynamics, biology, biochemistry, geochemistry, geology, hydrology, geomorphology, and atmospheric dynamics, including climate change. The literature is increasingly full of proposals about environmental barriers, glacial/interglacial cycles, sea‐crossings, land bridges, and adaptive specializations, but they often lack the means to evaluate their individual and combined impacts on hominid dispersal. The chapter highlights aspects relating to examples of three of these, namely sea level variations, deserts, and mountains.
Earth’s climate history is important for understanding the dynamics and feedbacks of the climate system. However, atmospheric sciences generally focus on shorter timescales, while geological sciences focus on longer timescales, but a unified picture is desired. This paper reviews the observations of Earth’s climate history from 4.5 billion years to one minute with emphasis on temperature, sea level, and atmospheric carbon dioxide. Earth’s climate history shows dominant climate modes such as the supercontinent cycles, interglacial cycles, millennial cycles, multi-decadal oscillation, interannual oscillation, seasonal cycle and diurnal cycle. The amplitudes of the dominant climate variability generally decrease from the billion-year timescales to interannual timescales, then significantly increase at subannual to diurnal timescales.
Principles of place, space and time can frame an understanding of the context and interpretation of Quaternary palaeo-records, and this is particularly the case for the varied proxies used for late Quaternary climate and environmental reconstruction in southern Africa. Place refers to the specific topographic setting or context of any one record, which has implications for the operation of physical processes in the landscape that control the accumulation of different records. Space refers to the spatial scale or footprint of any one record or proxy, and this varies from one proxy to another. Time refers to not only the time period covered by individual records, but also the temporal resolution of the record, which depends on accumulation rates and availability and quality of any radiometric dating. These three principles are discussed specifically in the context of the Quaternary of southern Africa and through the papers that form this special issue, but are also relevant globally. Future research directions in Quaternary research in southern Africa are identified, including opportunities for refining regional chronostratigraphies.
O desenvolvimento deste artigo surge em razão da distinção conceitual entre três grandes grupos de eventos climáticos baseados na durabilidade e ciclicidade temporal de determinada tendência dos fenômenos atmosféricos: mudanças climáticas, oscilações climáticas e pulsações climáticas. Assim, objetiva evidenciar cronologicamente a evolução de algumas bases teóricas-metodológicas responsáveis pela identificação de episódios paleoclimáticos vinculados aos conceitos estabelecidos. A análise foi conduzida de modo a destacar as primeiras constatações de eventos glaciais e interglaciais (mudanças climáticas), abordando antigas nomenclaturas e técnicas de identificação pautadas em datações relativas. A posteriori são promovidas discussões sobre a revolução dos isótopos cosmogênicos, responsável pelo aperfeiçoamento do reconhecimento das mudanças climáticas e primeiras identificações de oscilações climáticas. Trata-se especificamente dos estudos das razões de isótopos de oxigênio (16 O, 18 O) em foraminíferos de leitos marinhos, bem como das novas nomenclaturas desenvolvidas. Por fim, são abordadas discussões teóricas que evidenciam subsídios metodológicos das Geociências para identificação de pulsos climáticos de curta duração, ocorridos em escala de tempo recente da natureza a partir de distintos métodos de datação aplicados em inúmeros proxies/registros existentes. Verifica-se aperfeiçoamento da identificação de eventos paleoclimáticos de diferentes durabilidades e ciclicidades temporais, condizente com refinamentos metodológicos impulsionados por avanços tecnológicos inerentes às Ciências da Terra.
The advances in understanding of Quaternary geomorphology in the latter half of the 20th Century were closely linked with the improved knowledge of Quaternary climatic fluctuation, principally derived from isotopic evidence from ocean and ice cores. An important goal was finding terrestrial sedimentary records that can be correlated with the globally applicable isotopic sequence. From a geomorphological viewpoint, river terraces are paramount, particularly since they can provide semi-continuous sequences that record palaeoclimate and landscape evolution throughout the Quaternary, as well as the interaction of rivers with glaciation, sea-level change and notable geomorphological events. In coastal areas, shoreline terraces and raised beaches can provide similar sequences. The chapter discusses the progress made in understanding these archives and, in particular, the various mechanisms for dating and correlation, as well as touching upon contributions from other environments, namely slopes and karstic systems, as well as the role of soils in deciphering geomorphological evidence.
Mediterranean ecosystems contain some of the highest levels of plant diversity of any region on Earth and are amongst those believed to be most at risk from the consequences of global warming. Yet such ecosystems are not static and have responded to environmental changes at a variety of scales and from a variety of causes, particularly climatic and anthropogenic. The purpose of this paper is to review recent research on environmental change and ecosystem response. Long-term records are available to analyse changes over glacial-interglacial cycles, while high resolution records show the sensitivity and coupling of Mediterranean, North Atlantic and Greenland records. For the Holocene, there is continued debate about the relative impact of anthropogenic activity, but there is also increasing recognition that mediterranean-type ecosystems should not be regarded as fragile, degraded landscapes, but are disturbance- adapted. Nevertheless, conservation measures face increasing challenges from contemporary climate change and human pressures. Some insights into the identification of refugial areas, either in glacial times or for present-day conservation purposes, come from molecular Biogeographical studies of past faunal and floral distribution.
Identification of cultural groups is rare in the early Palaeolithic due to site formation processes including taphonomy and the effect of raw material and site function. This paper reviews a critical period in Europe at about 400 ka (MIS 11) when we may be able to identify such groups. This period, sees more sustained occupation and evidence of new technologies, including bone and wooden tools, hunting and fire-use. Importantly, brain size had begun to approach modern capacity. The fine-tuned record from Britain enables correlation of sites and new models of human behaviour to be developed. Millennial-scale changes in material culture can now be recognised, which can be interpreted as brief incursions by different cultural groups into Britain from mainland Europe. We suggest that population movement was primarily driven by changes in climate and environment. We further propose that variation in material culture is a reflection of local resources and landscape and that during stable environment localised expressions of culture emerge. This can be applied to Europe, where it is suggested that a complex mosaic of small-scale cultural groupings can be identified, some with and some without handaxes, but underpinned by a common set of technologies and behaviours.
The botanical and climatic implications of an abrupt climatic change recorded in several European pollen sequences are analyzed on the basis of four French sequences. This event, which had the same consequences as the “Younger Dryas” (cold and dry climate) is also recorded outside Europe. Its origin is unknown.
Observations of delta18O in five deep-sea cores provide a basis for developing a geological time scale for the past 780000 years and for evaluating the orbital theory of Pleistocene ice ages. The statistical evidence of a close relationship between the time-varying amplitudes of orbital forcing and the time-varying amplitudes of the isotopic response implies that orbital variations are the main external cause of the succession of late Pleistocene ice ages.
A detailed stable-isotope record is presented for the full length of the Greenland Ice-core Project Summit ice core covering the last 250,000 years according to a graduated timescale. It appears that the climatic stability of the Holocene is the exception rather than the rule; the last interglacial is also noted to have lasted longer than is implied by the deep-sea SPECMAP record. This discrepancy may be accounted for if the climate instability at the outset of the last interglacial delayed the melting of the Saalean ice sheets in America and Eurasia.
A geological time scale is only as useful as the stratigraphy to which
it is tied. The stratigraphy of deep-sea sediments of the Brunhes chron
is largely based on the 19 oxygen isotope stages defined by Emiliani
(1955) and Shackleton and Opdyke (1973). To improve the reliability and
precision of this isotope stratigraphy, we have applied the technique of
graphic correlation (Shaw, 1964) to isotopic events that can be
consistently recognized on a global scale. Accordingly, we have devised
a numerical taxonomy of isotope stratigraphy to include not only the 19
stage boundaries but also 56 isotopic events that are recorded as
δ18O maxima or minima within these stages. Because
samples are taken at discrete intervals, each event is recorded as a
depth range which depends both on the sampling density and the structure
of the isotopic record. Graphic correlation proceeds by selecting a
reference section (V28-238) and then graphing the depth range of
isotopic events that are common to both sections. The overlapping ranges
define correlation boxes, within which the true event must lie. The line
of correlation must pass through all correlation boxes. Surprisingly,
empirical tests have shown that correlation between stratigraphic
sections can be accomplished as a series of straight line segments. The
number of segments required and their slopes and offsets identify
changes in accumulation rate, stratigraphic gaps, and zones of
deformation. The line of correlation relates any level in a given core
to the standard section and enables all isotopic records to be recast on
the basis of a common depth scale. In this form, isotopic records can be
stacked (averaged) to construct a global average record that can be used
to differentiate between global and local isotopic variations.
Preliminary results with 13 deep-sea cores suggest that correlation may
be precise to within a few centimeters and will provide an accurate and
reliable method for the application of time scales in the Brunhes chron.
Using the concept of “orbital tuning”, a continuous, high-resolution deep-sea chronostratigraphy has been developed spanning the last 300,000 yr. The chronology is developed using a stacked oxygen-isotope stratigraphy and four different orbital tuning approaches, each of which is based upon a different assumption concerning the response of the orbital signal recorded in the data. Each approach yields a separate chronology. The error measured by the standard deviation about the average of these four results (which represents the “best” chronology) has an average magnitude of only 2500 yr. This small value indicates that the chronology produced is insensitive to the specific orbital tuning technique used. Excellent convergence between chronologies developed using each of five different paleoclimatological indicators (from a single core) is also obtained. The resultant chronology is also insensitive to the specific indicator used. The error associated with each tuning approach is estimated independently and propagated through to the average result. The resulting error estimate is independent of that associated with the degree of convergence and has an average magnitude of 3500 yr, in excellent agreement with the 2500-yr estimate. Transfer of the final chronology to the stacked record leads to an estimated error of ±1500 yr. Thus the final chronology has an average error of ±5000 yr.
Core Y72 II I (43 degrees 15'N, 126 degrees 22'W) contains sediment of oxygen isotope stages I through 6 (substages 5a through 5e are well developed) and abundant pollen from the nearby continent, enabling us for the first time to obtain a direct marine-continental correlation of events in the last interglacial sensu lato. From stage 6 to substage 5e the vegetational record resembles that during the waning of the last glacial. During substage 5e, after a rapid increase of alder, western hemlock was abundant and significant amounts of redwood, oak, and Douglas fir appeared. These results suggest that vegetation on the adjacent continent during substage 5e was similar to that of the temperate conifer forests which developed in the Pacific Northwest during the Holocene. The vegetation record since that brief episode (which like the Eemian in northwest Europe lasted only afew thousand years) has been complex.
A multidisciplinary study of the uppermost 10 m of the Pleistocene drilling of Valle di Castiglione is presented in this paper. The lithostratigraphic sequence can be summarized in five main intervals, from bottom to top: from 10.60 to 7.80 m brownish black slightly calcareous muds, containing volcanic material; from 7.80 to 5.30 m massive brownish black tuffites, with some burrow casts in the upper part; from 5.30 to 3.03 m grey calcareous muds with fresh-water fauna, with a thin layer of tuffite between 4.15 to 4.00 m; from 3.03 m to the ground level peaty muds with molluscs and then interbeddings of peat and muds. The whole sequence is probably continuous and deposited in low-energy shallow water environment. The uppermost 15.60 m of the sedimentary suite yielded ages spanning from about 3500 to nearly 42 000 yr before present (BP). Pollen analysis has provided two pollen diagrams (percentage and absolute) showing the history of vegetation from the full glacial to almost all the Holocene. -from Authors
A survey is made of pollen-analytical studies (some of them still unpublished) carried out in the Velay mountains (Massif Central, France). The analyses of three main sites (Lac du Bouchet, Praclaux and Ribains craters) enable one to propose a continuous palaeoclimatological sequence from the Holsteinian interglacial to the Holocene. As many as eight temperate episodes (major interstadials and interglacials) are described during the Eemian-Holsteinian interval. On the basis of these results a correlation is proposed between the Holsteinian and stage number 11 of the marine oxygen isotope stratigraphy. -Authors
In this paper the results of a palynological investigation of the 30-78 m interval from a deep bore hole in the Tenagi Philippon are presented. The pollen diagram reflects alternating steppe phases and phases of oak forest, some of them with an evergreen character. Taking the 14C dated last interglacial-glacial cycle (resp. forest and steppe) as a model, the oak phases are interpreted as interglacials or warm interstadials and the steppe phases mostly as glacials.The presence of pollen from evergreen oaks indicates warmer periods that might be called interglacials whereas the presence of only pollen from (semi) deciduous oak species indicates periods that might be called interstadials.
A core recovered from a thick sedimentary sequence in the Ioannina
basin, on the western flank of the Pindus Mountain Range, northwest
Greece, presents the opportunity to observe multiple changes in
vegetational communities at one locality through a series of
glacial-interglacial Quaternary cycles. The Ioannina 249 record adds to
the knowledge of vegetation history of areas of increased topographical
variability and precipitation of the western Balkans and provides a
complete stratigraphical record that can be compared with that of other
long terrestrial sequences and with the marine record. Pollen analytical
results are presented as percentages and concentrations, the former
providing information on the composition and structure of vegetation,
while the latter is considered here to be a reliable indication of
vegetation density when changes differing by an order of magnitude are
documented. The record shows an hierarchical order of variation in the
response of vegetation to environmental change. Higher order of
magnitude changes are alternations between forest and open vegetation
communities, a reflection of major climatic shifts from interglacial to
glacial modes. Superimposed on these oscillations is a lower order
variability associated with vegetation changes within interglacial and
glacial periods. During forest periods a succession is recorded with
Quercus and Ulmus/Zelkova expanding early, followed by Carpinus betulus
and also Ostrya carpinifolia/Carpinus orientalis, and finally Abies
often accompanied by Fagus. Although individual periods may be
characterized by dominance of one or more taxa, the underlying pattern
of differential expansion is usually distinct and consistent. Nine
forested intervals are distinguished and are assigned local names to
facilitate long-distance comparisons and correlations. During open
vegetation periods a series of changes is also observed from
transitional steppe-forest or forest-steppe vegetation, through
grassland steppe communities, culminating in a discontinuous
desert-steppe vegetation. In addition to the two ends of the spectrum
(forest and desert-steppe), attention is drawn to the intermediate
phases representing `average' Quaternary conditions. The Ioannina record
is correlated with that of other long sequences from Europe and
variation in the response of vegetation with site characteristics is
considered. A strategy for long-distance correlations relying on the
primary structure of vegetation and relative stratigraphical position of
individual periods is described. The last interglacial period followed
by two interstadials is recorded in much the same fashion in all
records. Correlation of earlier periods was also in general agreement
although only two continuous records that extend beyond the last
interglacial are at present available for comparison. To minimize
elements of circularity, similarities in the behaviour of individual
taxa during particular periods are not part of the correlation criteria
so that if their chronostratigraphical equivalence is independently
corroborated their significance can be examined. On this basis, the
importance of Carpinus betulus and the almost complete absence of Fagus
on a subcontinental scale during the last interglacial are noted.
Possible effects of climate, competition and disease are discussed.
Cross-correlation with the deep-sea oxygen isotope record provides a
tentative chronology for the Ioannina record. Based on this, the
sequence down to a depth of 162.75 m is considered to represent a record
of approximately the past 423 000 years. Aspects of land-sea
correlations are discussed in the light of the Ioannina 249 record and
the importance of long sequences in the development of European
Quaternary stratigraphy is emphasized.
In this article the palynological record of the Tenaghi Philippon III core (112.8–197.8 m) from the Philippi Plain in Greece is discussed. The arboreal pollen diagrams show an alteration of steppe phases (representing glacial periods) and oak forest phases (coinciding with interglacial periods). A proposal for a local biostratigraphy is given and a preliminary correlation is suggested with the Northwest European subdivision of the Middle Pleistocene.From the AP diagrams it appears that the flora is gradually impoverished in Arcto-Tertiary elements and obtains a more mediterranean character. In this section, however, the real mediterranean forest, rich in Quercus ilex/coccifera type is not yet present, which implies that a warm humid climate dominated with rainfall throughout the year.The presence of a great number of Tertiary pollen, two sterile intervals and clastic sediment in the lower part of the core, while from 181.6 m upwards organic sediment is found, indicates a change in sedimentation regime around a depth of 182 m. The sedimentation regime changed from fluvatile to lacustrine as a result of the aftermath of tectonic events.Chronostratigraphy of the diagrams is based on radiocarbon dates from the TF2 core, paleomagnetic polarity determinations in the TF3 core as well as interpolations between the two. In this way the core was dated at 900,000-approx. 600,000 yr B.P.A correlation with deep-sea Core V28–239 is proposed. From this correlation it appears that both in the diagrams and in the oxygen isotope curve the glacial and interglacial periods of the Middle Pleistocene are of a different wavelength and amplitude as compared to the ones of the Upper Pleistocene.
From the 120 m core of the Philippi Plain (Macedonia, Greece) the interval 78–120 m was palynologically analyzed. In this interval a series of steppe and forest phases of Middle Pleistocene age can be distinguished.A proposal for a local biostratigraphy is given and a preliminary correlation is suggested with the Northwest European subdivision of the Pleistocene. From this correlation it appears that within the Cromerian, an additional interglacial can be recognized. This interglacial is situated between the Cromerian II and the Cromerian III.A difference in climate can be observed between the interglacial phases of the lower part and the upper part of the diagram.
In this paper the results of a palynological investigation of a 120 m deep borehole in the Tenaghi Philippon, Macedonia (Greece) are given. These data show that during the Holocene mainly an oakwood forest was present. In the most recent part of the Holocene Fagus and Abies were also present. During the climatic extremes of the Weichselian an open vegetation existed. During the early interstadials a forest with Quercus, Fagus and Carpinus existed, whereas in the later interstadials stands of Pinus predominated. In the Late Glacial a not very dense oak forest was of some importance.
Profiles of O-18/O-16 ratios along three previous deep Greenland ice cores seemed to reveal irregular but well-defined episodes of relatively mild climate conditions (interstadials) during the mid and late parts of the last glaciation. Results are presented from a new deep ice core drilled at the summit of the Greenland ice sheet, where the depositional environment and the flow pattern of the ice are close to ideal for core recovery and analysis. The results reproduce the previous findings to such a degree that the existence of the interstadial episodes can no longer be in doubt. According to a preliminary timescale based on stratigraphic studies, the interstadials lasted from 500 to 2000 yrs; their irregular occurrence suggests complexity in the behavior of the North Atlantic ocean circulation.
THE emergent view of Quaternary cold stage European landscapes dominated by open vegetation communities has led to the concept that tree populations occurred only in restricted sites (refugia) in southern Europe1–5, although there is still considerable uncertainty over the precise location and extent of such populations. Trees respond to Quaternary climatic change by spreading from refugia during interglacials, but at the end of an interglacial period there is no reverse migratory movement in the direction of refugia, as most northern populations degrade in situ. It has thus been proposed that survival of European trees through Quaternary climatic cycles is dependent on populations persisting continuously in southern Europe6. According to this model, it is these southern populations that furnish European interglacial forests with essentially the same components during the Quaternary and, moreover, it is failure to survive in these 'long-term refugia' that brings about a tree species' ultimate disappearance from Europe6. I present here a 430,000-year record of vegetational and climatic change from northwest Greece comparable to that of other long sequences, but exceptional in documenting the continuous presence of temperate tree pollen throughout the sequence. The levels and consistency of representation suggest the local occurrence of tree populations at fluctuating densities and distributions according to prevailing climatic regimes.
A 46-m core of lake sediments, obtained from the center of the explosion crater of Praclaux (Haute-Loire, Velay, France), was studied on the basis of 368 pollen spectra. Five temperate forest episodes alternating with phases indicative of glacial climates are recorded. Two of these episodes show vegetation successions representative of full interglaciations; the oldest is contemporaneous with the Holsteinian interglaciation. A thick trachytic tephra permits correlation to be established with the pollen sequence from Lac du Bouchet. This comparison indicates the presence of two complete interglaciations between the Holsteinian and the Eemian that are the equivalents of marine isotope stages 7 and 9. The Holsteinian therefore corresponds to isotope stage 11.
A new 20 m sequence is presented which is based on 279 spectra derived from a coring at Le Bouchet lake (Massif Central, France). The vegetational history of this region is described back to the end of the last Interglacial (Ribains interglacial). The two Preglacial (early Glacial) forested interstadials (St-Geneys 1 and St-Geneys 2) are evidence for the first time in the Massif Central. In spite of the altitude of the site (1200 m), they suggest a quite temperate vegetation, with the same mesophilous character as during the Holocene. The Pleniglacial appears to be threefold, with two cold episodes (Lower and Upper Pleniglacial) divided by a long complex period of moderate climatic improvement. The vegetation history of this mountain region is compared with that evidenced for the same period on the basis of the sequence of Les Echets at a lower altitude (267 m). Botanical and climatic inferences are discussed.RésuméConstruite sur la base de 279 spectres polliniques, une nouvelle séquence de 20 m, prélevée par carottier dans le lac du Bouchet (Massif Central, France) est présentée. L'histoire de la végétation de cette région est révélée depuis la fin du dernier interglaciaire (interglaciaire de Ribains). Mis en évidence pour la première fois dans le Massif Central, les deux interstades forestiers du Préglaciaire (= glaciaire précoce) (St-Geneys 1 et St-Geneys 2) témoignent, malgré l'altitude de 1200 m, de végétations très tempérées, aussi mésophiles que celles de l'Holocène. Le Pleniglaciaire apparaît tripartite, comportant deux ensembles froids (Pléniglaciaire inférieur et Pleniglaciaire supérieur), séparés par une longue période complexe d'amélioration modérée. L'histoire de la végétation de cette région de montagne (1200 m) est comparée, pour la même période, à celle révélée par la séquence des Echets (267 m). Les implications botaniques et climatiques de cette comparaison sont discutées.
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