No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
The Holocene climatic optimum and pollen records of sapropel 1 in the eastern Mediterranean, 9000–6000BP
Abstract
The most recent sapropel in the deep eastern Mediterranean Sea has been deposited between 9 and 6 ka bp. Climate conditions, as revealed by the pollen records of this sapropel in marine cores, were most favorable for temperate deciduous trees, which is in agreement with the inferences from records of peripheral land pollen sites. The abundance of deciduous oak pollen is much higher than that of Artemisia (sage-brush), indicating that annual precipitation in the mid-elevation borderlands was at least 550 mm without summer drought, but more probably in the range 800–1300 mm. The pollen of Pistacia, which formed a savanna at low elevations, is also at its highest abundance and signals the absence of frost in winter, while being capable of withstanding summer drought. The early Holocene therefore appears as the post-glacial climatic optimum with the highest moisture and mildest winters. In southwest Asia, this is also the time of the Neolithic population explosion with incipient domestication of cereals, possibly following natural selection of the ‘tough rachis’ mutation in wheat and barley by the extreme aridity of the preceding Younger Dryas.
... However, though the Holocene has been generally very climatically stable it was punctuated by small amplitude oscillations on roughly a l.Skyr wavelength such as is observed during the Little Ice Age / Medieval Warm Period (Lamb, 1966) and other oscillations with even lower amplitudes and higher frequencies such as the El Nino Southern Oscillation (Rasmusson, 1985) and the North Atlantic Oscillation (Uppenbrink, 1999). In addition, between 9 and 6kyrs BP a period termed the Holocene Climatic Optimum, which is believed to coincide with a maximum in insolation, occurred (Rossignol-Strick, 1999;Kalis et al., 2003). At this time, global climate was slightly warmer than it is today (+2°C, up to + 4°C (Kalis et al., 2003)) and North Africa and the Mediterranean region experienced significantly increased precipitation (Rossignol-Strick, 1999). ...
... In addition, between 9 and 6kyrs BP a period termed the Holocene Climatic Optimum, which is believed to coincide with a maximum in insolation, occurred (Rossignol-Strick, 1999;Kalis et al., 2003). At this time, global climate was slightly warmer than it is today (+2°C, up to + 4°C (Kalis et al., 2003)) and North Africa and the Mediterranean region experienced significantly increased precipitation (Rossignol-Strick, 1999). This may have been significant enough to reduce or temporarily halt the anti-estuarine circulation of the Mediterranean (Myers et al., 1998), and allowed the stagnation of the deep Mediterranean which preconditioned the basin for the formation of saporopel SI (Casford et al., 2002). ...
p>Evidence is presented for the presence of the Azores Front in the northern Gulf of Cadiz prior to 16ka BP, and its subsequent withdrawal during the last deglaciation. It is conducted that the North Atlantic warm water sphere was comparable in extent to today during the latter parts of the last glaciation.
It is also proposed that the Mediterranean Outflow plume settled to greater depths during the last glaciation, on the basis that evidence for its presence is found on the Gil Eanes Drift (the lowermost part of the Gulf of Cadiz contourite) but is not found in the modern flow path of the plume. This observation is consistent with predictions made from the physical constraints on the current system, and will have significant and potentially wide-ranging impact for the circulation of the Atlantic at all depths. In addition to its direct influence, the relatively shallow settling depth of the modern Mediterranean Outflow plume may promote the formation of North Atlantic Deep Water and thus enhance the meridional overturning.
Sea-level/climatic variation are proposed as the cause of contourite cycles on both large and small scales. The implications of observed anti-phasing of depositional cycles on the Gil Eanes Drift and the rest of the Gulf of Cadiz drift are discussed. Sediment deposited on the Gil Eanes Drift is found to be ultimately sourced from southwestern Iberia, initially deposited on the continental shelf and then reworked onto the slope where it is energetically sorted by the waning Mediterranean Outflow Plume and deposited on the sediment drift.
High-resolution colour data scanning is proposed as a tool for palaeoceangraphy, both as a correlation tool and for delineation of sedimentary flux to a location. Supply of terrigenous material to the western Gulf of Cadiz is found to be significantly enhanced during glacial times.</p
... Sanlaville (1996) and Blanchet et al (1998) have attempted to synthesise the available evidence. These syntheses are supplemented by more recent results (eg Goodfriend 1999;Rossignol-Strick 1999), and will need to be modified as new studies are completed (eg Edwards et al 2002). The different lines of evidence cannot always be readily integrated, however, due to differences in scale of the phenomena studied and in particular because the chronological resolution of palaeoenvironmental indicators is poor. ...
... Only the Jordan River drains an area of higher rainfall than the Jordanian plateau, and it enters the country below sea level. Sanlaville (1996) Sanlaville's (1996) palaeoclimatic synthesis borrowed heavily on the analysis by Rossignol-Strick (1995) of pollen from several marine cores in the eastern Mediterranean, a project that subsequently expanded in scope (Rossignol-Strick 1999). A marker horizon of sapropel (sludge formed by the accumulation of incompletely-decomposed marine micro-organisms), dated to the period 9000-6000BP (ca 8300-5000 cal BC), was found across the eastern Mediterranean. ...
PhD thesis written between 1998 and 2004 when I was a student at La Trobe University, Melbourne, Australia.
... Avni, Chapter 2; Kushnir et al., Chapter 4 of this volume), subtle changes in regional climate patterns may induce huge changes over short spatial and temporal scales. During the past decade, several palaeoclimatic studies of this region ( Fig. 18.1) using marine (Rossignol-Strick et al. 1999;Kallel et al. 2000;Emeis et al. 2003) and continental palaeoclimate records (e.g. Frumkin et al. 2000;Bar-Matthews et al. 2003, Bar-Matthews 2014, and Chapter 17 of this volume; Kolodny et al. 2005;Verheyden et al. 2008;Develle et al. 2011;Ayalon et al. 2013;Vaks et al. 2013;Gasse et al. 2015, and Chapter 19 of this volume; Stein & Goldstein, Chapter 12 of this volume; Torfstein & Enzel, Chapter 13 of this volume) have revealed a complex regional climatic pattern, and more particularly, distinct north-south differences in precipitation variability. ...
... Speleothems, which form by cave dripwaters, i.e. rainwater minus water lost by evapotranspiration, recorded glacial-interglacial changes (Frumkin et al. 1999;Enzel et al. 2008) as well as episodes of sapropel development, linked to increased freshwater influx from the Nile River (Rohling et al. 2002Scrivner et al. 2004). Besides these source variations, lower δ 18 O values of speleothem calcite (δ 18 O ST ) are also suggested to be linked to higher amounts of rainfall (Bar-Matthews et al. 1997, 1999 with potential quantitative precipitation reconstructions based on δ 18 O ST (Bar-Matthews et al. 2003). This quantitative reconstruction was challenged by Frumkin et al. (1999Frumkin et al. ( , 2000, Kolodny et al. (2005), and Enzel et al. (2008). ...
... The extracted gas was purified for 10 min by two hot GP 110 and two GP 10 getters (ZrAl). Ar isotopes ( 36 Ar, 37 Ar, 38 Ar, 39 Ar and 40 Ar) were analysed by mass spectrometry using a VG5400 equipped with an electron multiplier Balzers 217 SEV SEN coupled to an ion counter. Neutron fluence J for each sample is calculated using co-irradiated Alder Creek Sanidine (ACs-2) standard with an age 47 of 1.1891 Myr and the total decay constant of a previous publication 48 . ...
... Ar/39 Ar ages from literature50,58,[63][64][65]67,[83][84][85][86][87][88][89][90] were recalculated using a decay constant48 and the ages of the ACs-2 47 of 1.1891 Myr or Fish Canyon sanidine 48 of 28.294 Myr. Tephra ages in bold are used for age-depth modelling in Fig. 1. ...
Mediterranean climates are characterized by strong seasonal contrasts between dry summers and wet winters. Changes in winter rainfall are critical for regional socioeconomic development, but are difficult to simulate accurately¹ and reconstruct on Quaternary timescales. This is partly because regional hydroclimate records that cover multiple glacial–interglacial cycles2,3 with different orbital geometries, global ice volume and atmospheric greenhouse gas concentrations are scarce. Moreover, the underlying mechanisms of change and their persistence remain unexplored. Here we show that, over the past 1.36 million years, wet winters in the northcentral Mediterranean tend to occur with high contrasts in local, seasonal insolation and a vigorous African summer monsoon. Our proxy time series from Lake Ohrid on the Balkan Peninsula, together with a 784,000-year transient climate model hindcast, suggest that increased sea surface temperatures amplify local cyclone development and refuel North Atlantic low-pressure systems that enter the Mediterranean during phases of low continental ice volume and high concentrations of atmospheric greenhouse gases. A comparison with modern reanalysis data shows that current drivers of the amount of rainfall in the Mediterranean share some similarities to those that drive the reconstructed increases in precipitation. Our data cover multiple insolation maxima and are therefore an important benchmark for testing climate model performance.
... The mid-Holocene (MH; 6 ka) is a period of profound cultural transition worldwide, particularly in the arid-semiarid belt of ∼ 30 • N (Sandweiss et al., 1999;Moss et al., 2007;Roberts et al., 2011;Warden et al., 2017). The MH climate, which belongs to the Holocene climatic optimum (Rossignol-Strick, 1999;Chen et al., 2003;Zhang et al., 2020), differs notably from that of the subsequent period. ...
The mid-Holocene (MH) is the most recent typical climate period and a subject of great interest in global pa-leocultural research. Following the latest Paleoclimate Mod-eling Intercomparison Project phase 4 (PMIP4) protocol and using a fully coupled climate model, we simulated the climate during both the MH and the preindustrial (PI) periods and quantified the effects of Earth orbital parameters (ORBs) and greenhouse gases (GHGs) on climate differences, focus-ing on the simulated differences in the Atlantic meridional overturning circulation (AMOC) between these two periods. Compared to the PI simulation, the ORB effect in the MH simulation led to seasonal enhancement of temperature, consistent with previous findings. In the MH simulation, the ORB effect led to a markedly warmer climate in the mid-high latitudes and increased precipitation in the Northern Hemisphere, which were partially offset by the cooling effect of the lower GHGs. The AMOC in the MH simulation was about 4 % stronger than that in the PI simulation. The ORB effect led to 6 % enhancement of the AMOC in the MH simulation, which was, however, partly neutralized by the GHG effect. Transient simulation from the MH to the PI further demonstrated the opposite effects of ORBs and GHGs on the evolution of the AMOC during the past 6000 years. The simulated stronger AMOC in the MH was mainly due to the thinner sea ice in the polar oceans caused by the ORB effect, which reduced the freshwater flux export to the sub-polar Atlantic and resulted in a more saline North Atlantic. This study may help us quantitatively understand the roles of different external forcing factors in Earth's climate evolution since the MH.
... The mid-Holocene (MH; 6 ka) is a period of profound cultural transition worldwide, particularly in the arid-semiarid belt of ∼ 30 • N (Sandweiss et al., 1999;Moss et al., 2007;Roberts et al., 2011;Warden et al., 2017). The MH climate, which belongs to the Holocene climatic optimum (Rossignol-Strick, 1999;Chen et al., 2003;Zhang et al., 2020), differs notably from that of the subsequent period. ...
The mid-Holocene (MH) is the most recent typical climate period and a subject of great interest in global pa-leocultural research. Following the latest Paleoclimate Mod-eling Intercomparison Project phase 4 (PMIP4) protocol and using a fully coupled climate model, we simulated the climate during both the MH and the preindustrial (PI) periods and quantified the effects of Earth orbital parameters (ORBs) and greenhouse gases (GHGs) on climate differences, focus-ing on the simulated differences in the Atlantic meridional overturning circulation (AMOC) between these two periods. Compared to the PI simulation, the ORB effect in the MH simulation led to seasonal enhancement of temperature, consistent with previous findings. In the MH simulation, the ORB effect led to a markedly warmer climate in the mid-high latitudes and increased precipitation in the Northern Hemisphere, which were partially offset by the cooling effect of the lower GHGs. The AMOC in the MH simulation was about 4 % stronger than that in the PI simulation. The ORB effect led to 6 % enhancement of the AMOC in the MH simulation, which was, however, partly neutralized by the GHG effect. Transient simulation from the MH to the PI further demonstrated the opposite effects of ORBs and GHGs on the evolution of the AMOC during the past 6000 years. The simulated stronger AMOC in the MH was mainly due to the thinner sea ice in the polar oceans caused by the ORB effect, which reduced the freshwater flux export to the sub-polar Atlantic and resulted in a more saline North Atlantic. This study may help us quantitatively understand the roles of different external forcing factors in Earth's climate evolution since the MH.
... In addition, the present-day Mediterranean climate -characterized by dry and hot summers and mild, wet winters -emerged gradually from c. 8850 cal. BC and was firmly established only between c. 5600-4000 cal BC (Combourieu-Nebout et al., 1998;Rossignol-Strick, 1999). ...
... BC centring around 6200 cal. BC (Rossignol-Strick 1999;Rohling et al. 2002;Rohling and Pälike 2005;Robinson et al. 2006). The water level of the Dead Sea dropped and fluctuated radically (Migowski et al. 2006), and precipitation in the Negev seems to have decreased around this period (Goodfriend 1991). ...
The southward diffusion of the Helwan point from the Levant to north-eastern Africa and the colonisation of the Nile Delta by Levantine immigrants during the 8th–7th millennia cal. BC has been argued by Near Eastern archaeologists, but has not been demonstrated with sound archaeological evidence. This study will summarise old and new information about side-notched and tanged projectile points found in north-eastern Africa and consider their possible connection to the Levantine counterparts.
... Sapropel layers are common in Miocene, Pliocene and Quaternary sediments on the floor of the Mediterranean (Lourens et al., 1996;Kroon et al., 1998;Cramp & O'Sullivan, 1999;Larrasoaňa et al., 2003). The anaerobic conditions that enable sapropels to form are widely considered to result from a change in seawater stratification caused by a substantial influx of freshwater from major rivers such as the Nile (Rossignol-Strick et al., 1982;Rossignol-Strick, 1985, 1999. Rossignol-Strick et al. (1982) were the first to suggest that changes in the strength of the African summer monsoon were controlled by the earth's precessional cycle, which is related to the season of the year in which the earth is closest to the sun and is controlled by the direction in which the spin axis of the earth points in space, with an average cycle duration of about 20,000 years. ...
Late Quaternary environments in the Nile Basin reflect the influence of the African summer monsoon upon plant cover, sediment yield and flood discharge in the Ethiopian and Ugandan headwaters of the Nile. Intervals of prolonged and very high Nile flow coincide with times of stronger summer monsoon and have been dated using a combination of 14C, OSL and 10Be methods. Periods of high Nile flow into the eastern Mediterranean coincide with the formation of highly organic sedimentary layers termed sapropels. Ages obtained so far for these times of sustained middle to late Pleistocene high flow in the Blue and White Nile are broadly coeval with sapropel beds S8 (ca 217 ka), S7 (ca 195 ka), S6 (ca 172 ka), S5 (ca 124 ka), S4 (ca 102 ka) S3 (ca 81 ka), S2 (ca 55–50 ka) and S1 (10–6.5 ka). Sapropel 5 (ca 124 ka) was synchronous with extreme Blue Nile floods and the formation of the 386 m lake in the lower White Nile Valley, as well as with a prolonged wet phase in the eastern Sahara. Fluctuations in Nile flow and sapropel formation reflect the influence of the precessional cycle upon the East African monsoon. Between 75 ka and 19 ka the climate in the Nile headwaters region became progressively colder and drier. During the Last Glacial Maximum, Lake Tana in Ethiopia and Lake Victoria in Uganda became dry, flow in the White Nile was reduced to a trickle, and the Blue Nile and Atbara became highly seasonal bed–load rivers. The return of the summer monsoon at 14.5 ka ushered in extreme Blue Nile floods, widespread flooding across the Nile Basin and the formation of the 382 m lake in the lower White Nile Valley. There was a brief return to aridity during the Younger Dryas (12.8–11.5 ka), after which the climate again became wetter and widespread flooding in the Nile Valley resumed. The early Holocene floods were later followed by incision and creation of the modern relatively narrow flood plain.
... Deciduous oak abundances are commonly used as indicators for midelevation, relatively humid forest across the Mediterranean region (e.g., refs. 21,74,75). Assemblage change over time was summarized through DCA incorporated in past version 3.21 (76) on all upland tree and herb taxa >1% (SI Appendix, Figs. S3 and S4). ...
Significance
Forest conservation and restoration are important means to counter threats caused by habitat fragmentation and global change. Diverse and resilient forests can only be maintained if we understand their sensitivity to past climate change. The sedimentary record of the oldest extant lake in Europe, Lake Ohrid (North Macedonia, Albania), shows the survival and extinction of tree species during glacial and interglacial stages (G–IG) of the Quaternary. Pollen analysis reveals that the area was an effective refuge for tree populations through G–IG periods. The lake body locally buffered the climate, allowing repeated recovery of tree populations that were close to disappearance. However, extended periods of aridity during G–IG intensification after 0.94 Ma caused many tree taxa to disappear.
... The inferred wet period is supported by the PCA analysis, where the high values of AP, Artemisia, Poaceae and (A + P)/C on the left side of the diagram (Fig. 6) indicate a humid period for the subzone NEOR-Ia, which is further characterised by the occurrence of local aquatic taxa. Pollen records from the eastern Mediterranean (Rossignol-Strick 1995, 1999 suggest that a wet period prevailed from 9000 to 6000 cal a BP. Speleothem δ 18 O values from the Soreq cave in Israel also revealed several short wet periods, 20 to 100 years long, from 6800 to 6100 cal a BP (Bar-Matthews et al., 2003;Bar-Matthews and Ayalon, 2011). ...
Palynological and geochemical analyses provide valuable information about modern and past climatic regimes and vegetation. The impact of climate and humans on past vegetation in the semi-arid areas of northwestern Iran has received increased interest in the wake of warming temperatures in the Middle East. Palynological and down-core XRF elemental abundances from a peat core from Lake Neor enabled a reconstruction of vegetational changes of the past 7000 years over the highlands of northwestern Iran. Periods of increased arboreal pollen (AP) types and high (Artemisia + Poaceae)/Chenopodiaceae ratios along with low titanium abundances, high percentages of total organic carbon, more negative δD values, and higher carbon accumulation rates suggest a relatively wet climate. These conditions have persisted during the periods 6700-6200, 5200-4450 and 3200-2200 cal a BP. The overall low AP values, substantial rise of Chenopodiaceae, high Ti abundances and low values of palaeo-redox proxies, are all evidences of a drier climate, as has been reconstructed for the periods 6200-5200 and 4030-3150 cal a BP and the last 2200 years. An important feature of the last centuries is the increase of anthropogenic and pastoral indicator pollen types. Our results may provide basic data to predict future trends in vegetation dynamics under future climate change in western Asia.
... Although it is generally agreed that the Younger Dryas simultaneously shows a trend toward drier conditions (Bar-Matthews et al. 1999Verheyden et al. 2008;Robinson et al. 2006;Rossignol-Strick 1995), some uncertainties remain (Hartman et al. 2016;Meadows 2005). Climate changes during the Younger Dryas may have been a factor in the transition to agriculture, although this remains a matter of substantial debate During the Early Holocene (c.9500-6000 cal BCE) the climate remained both cooler and wetter than the present day, with a shift toward warmer and wetter conditions compared to the preceding period (Bar-Matthews et al. 1997Eriş et al 2018;Roberts et al. 2008;Rossignol-Strick 1999;Verheyden et al. 2008). Despite significant regional variation, events of punctuated aridity are suggested to have occurred around 8200 cal BCE, 7300 cal BCE and 6200 cal BCE (Fleitmann et al. 2008;Flohr et al. 2016; see also contributions in Biehl & Nieuwenhuyse 2016). ...
Understanding the organisation of food production is vital for understanding ancient societies. Multiple factors may influence decision making, including the local environmental capacity of a given area and individual and cultural preferences. This study compares zooarchaeological data from sites across the length and breadth of the Holocene Near East with modelled patterns of land use. The goal is to determine how far variation in the capacities of local landscapes impacted the choices made in animal production. Our approach allows us to investigate trends through time as well as between different regions of the Near East. The spatial and temporal scales employed also mean we can investigate the relationship between food production and climate trends. We find substantial patterning in the choices made in animal production, reflecting complex and regionally diverse production approaches. We demonstrate a prioritisation of individual and societal preferences to produce specific animals which is rarely impacted by either short or long term changes in aridity. We also find that the emergence of urban sites has a major impact on provisioning structures, and argue that the resulting organisational forms may have resulted in urban sustainability at the expense or rural sites.
... Les séquences holocènes continues, qui fournissent des courbes d'indicateurs paléoenvironnementaux bien datées et sur lesquelles s'appuient les études dans le Sud-Est anatolien et en Mésopotamie du Nord, sont clairsemées en périphérie, dans des régions dont les caractères climatiques sont différents de ceux du piémont syrien : en mer Méditerranée orientale (Rossignol et Strick, 1999), nord-Levant (Niklewski et van Zeist, 1970 ;Yasuda et al., 2000), Anatolie orientale (Bottema, 1995 ;Wick et al., 2003), Anatolie centrale (Roberts et al., 2001), Anatolie méditerranéenne (Kuzucuoglu et al., 2001). Ces séquences ont enregistré une croissance de l'humidité de l'Holocène inférieur jusque vers 6500-6000 cal. ...
... We are aware that closure and opening of the system could arise from changes in climatic and hydrologic conditions as well. However, we do not expect significant variations in the limited time span studied here when the Holocene climatic optimum was attained (Giraudi et al., 2011;Rossignol-Strick, 1999). The hypothesis is corroborated by the observation that, when more than one single age determination is available for postevent layers as in the case of COLA-1, COLA-2, and COLA-4 from Room D, their value overlap or is very close. ...
Speleoseismological research carried out in the Central Apennines (Italy) contributed to understanding the behavior of active normal faults that are potentially able to generate Mw 6.5–7 earthquakes documented by paleoseismology and by historical and instrumental seismology. Radiometric (U‐Th, AMS‐¹⁴C, and bulk‐¹⁴C) dating of predeformation and postdeformation layers from collapsed speleothems found in Cola Cave indicates that at least three speleoseismic events occurred in the cave during the last ~12.5 ka and were ostensibly caused by seismic slip on one or more of the active faults located in the region surrounding the cave. We modeled the collapse of a tall (173 cm high) stalagmite to find a causative association of this event with one among the potential seismogenic sources. We defined the uniform hazard spectrum (UHS) for each seismogenic source at the site, and we used the calculated spectra in a deterministic approach to study the behavior of the speleothem, through a numerical finite element modeling (FEM). Although our analysis suggests the “Liri” fault as the most likely source responsible for the ground shaking recorded in the cave, the “Fucino” fault system, responsible for a Mw 7 earthquake in 1915, cannot be excluded as a potential source of speleoseismic damage. Results of this work provide new constraints on the seismotectonic history of this sector of Central Apennines and highlight the performance of integrated speleoseismological, seismic hazard, and numerical studies.
... In this scenario, tephra would be remobilized prior to its fixation by vegetation, which can occur in less than a few decades under temperate climate conditions (e.g., Dugmore et al., 2018). Considering early Holocene humid and warm conditions in Central Anatolia (Rossignol-Strick, 1999), fixation might have occurred even faster, lending plausibility to the hypothesis of Dikkartın ash redeposition happening within a timeframe well below the resolution of available geochronometers, which would also be required by the occurrence of S1 tephra as a discrete layer in core SL112 (see Fig. 2 in Hamann et al., 2010). ...
"Levantine ash" was first described around Cyprus 45 years ago, but it took until the last decade to be rediscovered in the Yammouneh basin (Lebanon) and a sediment core offshore Israel. It was subsequently named "S1 tephra" based on its stratigraphic position within the lower part of the eponymous sapropel layer, the youngest in the Mediterranean. More recently, S1 tephra was also reported to be preserved in sediments of the Dead Sea, Tayma paleolake (Saudi Arabia), and Sodmein cave (Egypt).
The Dikkartin dome eruption of Mt. Erciyes (Central Anatolia, Turkey) has been postulated as the source of the S1 tephra based on major element and morphological analyses of volcanic glass shards. However, this correlation remained tenuous because radiometric dating and differentiation between Dikkartin and other young dome eruptions at Mt. Erciyes as potential sources were lacking. Here, we present the first radiometric age of 9.0 ± 0.6 ka (1 σ, n = 19) for the explosive Dikkartin eruption, based on internally consistent zircon double dating by (U-Th)/He and U-Th disequilibrium methods. New field observations and comprehensive major and trace element compositions determined for glass shards from proximal and distal samples confirm the explosive Dikkartin eruption as the source of S1 tephra.
Isopleths of maximum lithic clast sizes of the predominantly southeasterly-distributed fall deposit translate into eruption column heights of ca. 23 km and a VEI 4 or 5 (volcanic explosivity index; >0.4 km³ of tephra) category for the Dikkartin eruption. Furthermore, our data identify the nearly coeval Karagüllü dome eruption of Mt. Erciyes (Central Anatolia, Turkey) as the source of another tephra presently only documented for the southeastern Black Sea, indicating a northeastern distribution of this fall deposit.
With its dispersion covering the western part of the Fertile Crescent and its Early Holocene age, S1 tephra is identified as a key marker horizon in the center of the Neolithic revolution, both in space and time. Identification of the Dikkartin tephra across a broad proximal area from the northeast to the south of Mt. Erciyes may reflect a long-duration eruption that dispersed into multiple wind fields and across multiple seasons. By contrast, the Karagüllü tephra to the northeast of Mt. Erciyes is consistent with a winter eruption (October to April) assuming present-day stratospheric wind patterns. Modelling of tephra dispersal is ongoing.
... In this scenario, tephra would be remobilized prior to its fixation by vegetation, which can occur in less than a few decades under temperate climate conditions (e.g., Dugmore et al., 2018). Considering early Holocene humid and warm conditions in Central Anatolia (Rossignol-Strick, 1999), fixation might have occurred even faster, lending plausibility to the hypothesis of Dikkartın ash redeposition happening within a timeframe well below the resolution of available geochronometers, which would also be required by the occurrence of S1 tephra as a discrete layer in core SL112 (see Fig. 2 in Hamann et al., 2010). ...
Deposition of early Holocene Eastern Mediterranean S1 tephra and a Black Sea cryptotephra coincides with cultural transitions in the Fertile Crescent termed the Neolithic Revolution as well as sapropel formation during climate variability of the African humid period, classifying them as paramount regional marker horizons for archaeology as well as paleoclimatology. Their correlations with specific eruptions of the Mt. Erciyes stratovolcanic complex (Central Anatolia) remained inconclusive though. Here, we use zircon double-dating by (U-Th)/He and U-Th disequilibrium methods, major and trace element tephra glass geochemistry, and probabilistic modeling of tephra dispersal in an attempt to characterize all major late Quaternary proximal tephras of Mt. Erciyes, and to correlate them with distal deposits. Furthermore, we discuss contrasting proximal and distal tephra dispersal.
Three nearly-coeval rhyolitic satellite domes (Dikkartın, Perikartın, and Karagüllü) erupted at Mt. Erciyes in the early Holocene, and their dome extrusions were all preceded by explosive phases producing pyroclastic material that formed tephra fall and pyroclastic flow deposits. The new eruption age of 9.03 ± 0.55 ka (1σ uncertainty here and elsewhere) for proximal Dikkartın pumice is consistent with 14C-based S1 tephra chronologies in distal locations averaging 8.92 ± 0.03 cal ka BP. Perikartın pyroclastic flow deposits predate S1 tephra by ca. 0.8 ka according to a pair of published 14C ages, and strati-graphically overlie Karagüllü fallout , here dated to 8.2 ± 1.8 ka. Previously undated proximal tephras of Mt. Erciyes erupted in the Late (85.2 ± 4.9 ka) and Middle Pleistocene (154.5 ± 5.3 ka). S1 tephra glass is chemically similar to that of Dikkartın fallout , but also indistinguishable from that of Perikartın fallout. Karagüllü pumice is characterized by a distinct glass chemical composition, which correlates with that of unnamed cryptotephra reported for the southeastern Black Sea instead, where these results call for a re-evaluation of existing age models.
Maximum lithic clast size isopleths for proximal Dikkartın fallout indicate eastward dispersal of a 20 ± 5 km high eruption plume by stratospheric winds, in agreement with results of probabilistic tephra dispersal modeling. This azimuth contrasts with the known distribution of S1 tephra at distal locations that are all south of Mt. Erciyes. Significant tephra occurrences at up to 1300 km distance and orthogonal to prevalent stratospheric wind directions either result from very atypical wind conditions (probability ≪10 %), or are caused by tephra transport by prevailing low altitude winds. Two scenarios are proposed for low altitude transport: eolian reworking of primary fallout (more likely from the more widespread Dikkartın deposits), or co-ignimbrite ash cloud dispersal (more likely from the Perikartın eruption which predominantly produced pyroclastic flows). Because S1 tephra is chemically indistinguishable from both Dikkartın and Perikartın by major and trace element glass compositions, its exact source and dispersal mechanism remain ambiguous, although existing 14C ages for Perikartın predating those for S1 tephra favor Dikkartın as its source.
... The early-Holocene period (9.5-7 ka BP) that encompasses the second IDF event of 7.8 ka is also regarded as the wettest phase of the last 25 ka years in the Levant and Eastern Mediterranean (Robinson et al., 2006). A rich pollen record of humid species in the Middle East (Rossignol-Strick, 1999), a significant rise of lake levels in the Levant and Dead Sea (Frumkin et al., 1994), and oxygen isotope cave speleothem records that progressively shift to more negative values ( Bar- Matthews et al., 2003) all indicate warmer and wetter conditions during the early Holocene. All these paleoclimatic data strongly suggest that two major events in IDF c. 18.7 ka and 7.9 ka BP correspond to favorable humid periods when conditions of antecedent precipitation might have been satisfied. ...
Mass instability in the uplifting footwall blocks of normal faults involves a range of regional and local factors including, among others, climatic setting, topography, lithology and particularly ground shaking during earthquakes. Morphological and sedimentological investigations backed by 14C dating on a huge debris flow and its zone of depreciation provided favorable insights for dynamics and causative factors of this mass wasting. Our observations showed that I˙smetpaşa Debris Flow with a volume of 96 km3 involves three individual flows of decreasing significance in the late Pleistocene–Holocene period. The primary flow occurred in relation to a huge landslide developed on highly fractured and altered basaltic lavas near the crest of fault scarp c. 18.7 ka BP and probably conditioned by high precipitation rates in the early Interglacial. Although, most of the blocky debris flow transferred into the neighboring graben to form a 2 km wide debris fan, some remnant blocks and flow-induced valley-side slickensides can still be observed in the zone of depreciation. One km long secondary flow was sourced from the remnants of primary flow and was realized at 7.9 ka BP in another humid period of the Holocene. The third, though minor (less than 100 m long), mobilization of the flow occurred on one of the steep faces of secondary flow in 1960s when the mean precipitation was higher than that of today. Good coincidence of timing of individual debris flows with the humid phases of the late Pleistocene–Holocene period showed that long-term antecedent precipitation is the dominant causative factor.
... Intensified precipitation and growing temperatures characterized the beginning of the Holocene, even if they were limited to the higher-lying regions where conditions were the most severe. Forest expansion was noted nonetheless throughout the Near East (Rossignol-Strick 1999;Roberts 2002). In the Middle Euphrates, this process is attested by the presence of pistachio and almond at the younger sites of the discussed period, such as Jerf el-Ahmar and Dja'de (Willcox 1996). ...
Permanent architecture in the Near East first developed in the Northern Levant and it was a multi-faceted process as indicated by the archaeological data. Preferences for construction materials is an aspect that is seldom discussed with regard to early Neolithic architecture of the Northern Levant, while it is extremely interesting in the light of local geomorphological and environmental conditions. The article explores this aspect, reviewing the sources and the context, that is, the environmental changes that played a role in the development of early permanent architecture, going on to present the relations between local preferences for building materials and the nature of the environmental zones in various regions of the Northern Levant.
... We report geochemical data of carbonate pendants from soils surrounding Tell Chuera (Figs 1 and 2), which is situated in north-eastern Syria in a climatic transition zone between dry-summer Mediterranean (Csa) and semi-arid climate conditions (BSk, Kottek et al. 2006). Published palynological and geochemical information of the region is obtained from lacustrine deposits (Bottema 1995, Litt et al. 2014, Pickarski 2014, Pickarski et al. 2015, Roberts et al. 1999, Snyder et al. 2001, Stevens et al. 2001, Wick et al. 2003, Yasuda et al. 2000, marine sediments (Langgut et al. 2011, Rossignol-Strick 1999, speleothems (Bar-Matthews et al. 1997, Frumkin et al. 1999, as well as pedogenic carbonate (Pustovoytov et al. 2007). Nevertheless, there is still a deficit of (high-resolution) paleoclimatic information for parts of the Fertile Crescent due to the lack of deposits that are suitable for paleoecological reconstructions. ...
Stable isotope geochemistry of pedogenic carbonate is a powerful tool to obtain information about paleoenvironmental patterns. Here, we study up to 18 cm long pedogenic carbonate pendants which occur in highly calcaric soils near the Early Bronze Age site of Tell Chuera in north-eastern Syria. Two of these pendants were selected for stable carbon (δ13C) and oxygen (δ18O) isotope analysis. The data (-9.0 to 2.4 ‰ for δ13C and 23.9 to 27.0 ‰ for δ18O values) suggest that the vegetation present in the area during carbonate precipitation changed considerably and generally consisted of a mix of C3 and C4 plants with temporary dominances of the latter. Three radiocarbon ages between 43 and 35 ka BP indicate that the pendants formed almost entirely during the Upper Pleistocene with high growth rates of 4.1 to 9.7 mm/1000 a. Modern soils in the surrounding of Tell Chuera show carbonate precipitation in soil depths of about 40 cm, suggesting that the studied carbonate pendants were formed in similar depths. Today, the sampled pendants are found ca. 10 to 30 cm below the soil surface, hence topsoil was probably eroded, possibly due to agriculture. The tops of the remains of limestones, which serve as nuclei for carbonate precipitation, were probably capped. Porous surfaces indicate later dissolution of the pendants, which continues even to the lowermost part. We conclude that carbonate precipitation stopped ca. 31 ka ago, possibly due to changing local climatic conditions. Comparisons with other environmental archives show that the investigated carbonate pendants in the soils around Tell Chuera have the potential to serve as an useful archive for paleoenvironmental reconstruction.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
A unique interdisciplinary study of the relationships between climate, hydrology and human society from 20,000 years ago to the present day within the Jordan Valley. It describes how state-of-the-art models can simulate the past, present and future climates of the Near East, reviews and provides new evidence for environmental change from geological deposits, builds hydrological models for the River Jordan and associated wadis and explains how present day urban and rural communities manage their water supply. The volume provides a new approach and new methods that can be applied for exploring the relationships between climate, hydrology and human society in arid and semi-arid regions throughout the world. It is an invaluable reference for researchers and advanced students concerned with the impacts of climate change and hydrology on human society, especially in the Near East.
Fossil remains of European Roller (Coracias garrulus) in Croatia are relatively rare. European Roller has been found at four sites situated at the Adriatic coast: Marlera I and Šandalja II on northern Adriatic, and Vela spila and Markova spilja on southern part. Oldest find is from Marlera I, dated to the Late Pleistocene (Marine Isotope Stage 3 - MIS 3) and the youngest are the Holocene (MIS 1) finds at Vela spila and Markova spilja. Immature bones were found in Vela spila deposits, indicating breeding during the Late Pleistocene at the southern Adriatic. So far, European Roller has not been determined in the deposits from continental part of Croatia.
p>This thesis provides detailed multi-proxy records from six sediment cores in the Aegean Sea Levantine Basin, including high-resolution (1 cm to 0.5 cm) faunal records of planktonic foraminifera; stable isotope data for oxygen and carbon based on the same samples; and inorganic geochemistry records. The study interprets changes in palaeo-circulation as the result of climatic change, acting on several different time scales. This approach combines glacial inter-glacial warming, procession driven monsoon variation and cooling events acting on the 1450 year and 2300 year cycles.
It investigates longer-term variability during the Late Glacial and Holocene, in particular that associated with the deposition of the early Holocene dysoxic/anoxic sapropel S1. Concentrating on the onset of sapropel-forming conditions we identify the start of 'seasonal' stratification and highlight a lag in δ<sup>18</sup>O response of the planktonic foraminifer N. pachyderma to Termination T1b as identified in the δ<sup>18</sup>O record of G. ruber . By use of a simple model, it is determined that this offset cannot be a function of bioturbation effects. The lag is in the order of 1 kyr and suggests that isolation of intermediate/deep-water preceded the start of sapropel formation by up to 1.5 kyr. Using this discovery, the author proposes an explanation for the major unresolved problem in sapropel studies, namely the source of nutrient supply required for export productivity to reach levels needed for sustained sapropel deposition. It is suggested that nutrients had been accumulating in a stagnant basin for 1 -1.5 kyr and that these accumulated resources were utilized during the deposition of S1. In addition, the study provides a first quantitative estimate of the diffusive (1/e) mixing time scale for the eastern Mediterranean in its "stratified" sapropel mode, which is of the order of 450 years.
Using four high sedimentation-rate marine cores with suppressed bioturbation effects, recovered along the northern margin of the eastern Mediterranean. It is demonstrated that the study region, central to the development of modern civilisation, was substantially affected throughout the Holocene by a distinct cycle of cooling events on the order of 2 C-degrees.</p
Akko/Acre, a UNESCO World Heritage site since 2001, is one of the oldest continuously inhabited sites in the eastern Mediterranean. Tel Akko was a major maritime centre of the southern Levant from the Middle Bronze to the Late Persian period. The city was then moved 1500 m to the west on the Akko promontory where the ‘Old City’ of Saint-Jean d'Acre is located. The natural and anthropogenic evolution of Tel Akko area is reflected by persistent geographical and habitation pattern changes. We combined sedimentological and faunal analyses of radiocarbon dated cores as well as identification of ceramic sherds found in the cores with ground penetrating radar investigations to propose an up-to-date palaeogeographical reconstruction of landscape/environmental changes of the Akko plain in order to understand the extent to which environmental pressures have played a role on the position of anchorage and habitation patterns. We highlight how the local population make use of the natural advantages of the area and adapted to environmental pressures. Following a constant sedimentary input and simultaneous coastal progradation of the Akko coastal plain the main anchorage areas where forced to move. While the 2nd Millennium BC anchorage was on the southern area of the tell, the late-1st Millennium BC (Phoenician-Persian) anchorage was relocated on the western area. Vicissitudes in settlement pattern noted in archaeological excavations and surveys on Tel Akko have, most likely, been the consequence of the changes in the position of the coastline.
The lacustrine sediments and geomorphological data from the Bor Plain situated at elevations between 1050 and 1100 m in southern Central Anatolia provide record between 9800 and 6700 yr cal BP of climate changes and events. The main aim of this study is to determine the relationship between the location of Neolithic sites and the deposition and recession phases of the lake during Holocene. The geomorphological history of the Bor Plain and palynological results allows us to reconstruct the relationship between the Holocene environment and reconstruction of Neolithic settlements within a spatially well-defined lacustrine landscape of ~ 600 km2. A 75 ± 13 ka aged terrace, consisting almost entirely of calcite and situated about 76 m above the plain floor, indicates that the plain was covered with a paleolake in the transition from MIS 5 to MIS 4. Considering the low total organic carbon and the high CaCO3 clay values, we conclude that the lake slowly receded in 9867 ± 39 cal BP. However, the presence of aquatic herbaceous forms such as Nymphaceae and Cyperaceae indicates an increase in the water level of the lake during 6776 ± 35 cal BP, after which it transitioned to a dried lake. Thus, the progression and recession phases of the lake became the determining factor in the site selection of Neolithic settlements on mounds by which are found the plain floor at elevations between 1090 and 1100 m in this period on the Bor Plain.
The ultimate establishment of the agricultural economy in the central zone of the Fertile Crescent took place in the late Pre-Pottery Neolithic (PPNB), while the heyday of symbolism, establishing complex social relations among the population of Northern Mesopotamia occur in the era of the early Pre-Pottery Neolithic (PPNA). In this period, the domestication of any plant species is not yet registered in South-Eastern Anatolia (an area where the long-term intertribal cult center of Gbekli Tepe was found) unlike the neighboring Levant. The paper discusses possible models for the producing economy establishment in the region, analyzes materials suggesting that the ritual practices of the transition period to the Neolithic in some cases could contribute to the emergence and new economic strategies spread on the territory of Northern Mesopotamia. At the same time, the comparison of the climatic changes scientific studies results, archeobotanical and archaeozoological collections and material evidence of the development of social and spiritual life from Epipaleolithic and early Neolithic monuments of Northern Mesopotamia shows the coevolution/mutual influence of people and the surrounding natural environment. In our opinion, on the basis of the available data it is impossible to assert the primacy of the symbol revolution in the process of Neolithization in relation to early attempts at plant cultivation.
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.
Zusammenfassung
Die Küstenebene von Boukka befindet sich am Ostrand des Ambrakischen Golfs in
Nordwestgriechenland. Mit Hilfe paläogeographischer Methoden (Kapitel 5) wurde die
holozäne Landschaftsgenese rekonstruiert (Kapitel 6 und 7).
Die Ergebnisse belegen, dass das Ionische Meer bereits deutlich vor 5000 cal BC
in das Ambrakische Becken ingrediert war. Der relative Meeresspiegel am Ostrand des
Golfs stieg seither kontinuierlich an und weist aktuell den holozänen Höchststand auf.
Eine Trennung der Einflussfaktoren (Klima, Tektonik, Sedimentlieferung, Mensch) ist
anhand der vorliegenden Daten nicht möglich. Jedoch konnte mit Hilfe von Vergleichsdaten aus dem nordwestlichen Uferbereich des Ambrakischen Golfs eine starke tektonische Subsidenz des Arbeitsgebietes belegt werden. Der Ostrand des Golfs senkte sich etwa zwischen 5000 und 1000 cal BC relativ zu seinem nordwestlichen Ufer, das in diesem Zeitraum möglicherweise von Hebung betroffen war, um durchschnittlich
1,43 m pro Jahrtausend ab. Anschließend verlief die tektonische Bewegung in beiden
Teilgebieten ähnlich. Dies ist auf eine Veränderung lokaler tektonischer Prozesse
zurückzuführen. Erhöhte durchschnittliche Sedimentationsraten konnten für die südliche Küstenebene für das Neolithikum und für die Zeit seit der Klassischen Antike nachgewiesen werden, während die Werte im nördlichen Teilbereich seit dem Chalkolithikum rückläufig sind. Phasen erhöhter fluvialer Schüttung aus dem Gebirgsraum sind anhand der Sedimentkerne zwar detektierbar, allerdings wurde die zeitliche Einordnung aufgrund fehlender Datierungen zumeist nur grob abgeschätzt. Eindeutige Aussagen, ob sich anthropogene oder klimatische Einflüsse vorrangig für verstärkte Erosion verantwortlich zeichnen, können nicht getroffen werden.
Bezüglich der Entwicklung der Küstenebene kann festgehalten werden, dass der
Hügel Agrilovouni am Westrand der Ebene während des erfassten Zeitraums wohl nie
eine Insel darstellte. Zur Zeit des Peloponnesischen Krieges existierten östlich des
Hügels flache Seen, während sich nördlich und südlich Revmabetten anschlossen. Sollte
sich hier also tatsächlich die antike Schiedsstätte Olpai (vgl. Kapitel 3) befunden haben,
so war diese wohl vor allem in den Wintermonaten nur selten trockenen Fußes zu
erreichen. Die nördliche Lagune hat sich wahrscheinlich zwischen 1500 und 500 cal BC
durch den Aufbau von Sandnehrungen deutlich vergrößert. Im südlichen Bereich der
Küstenebene existierte über lange Zeit ebenfalls eine Lagune, die erst nach 1945
endgültig von Revmasedimenten aufgefüllt wurde.
Fluviale Schüttung ist der entscheidende Einflussfaktor auf die holozäne
Landschaftsgenese des Arbeitsgebietes. Die Untersuchungen ergaben vielfältige
Anhaltspunkte für Verlagerungen der Revmaverläufe innerhalb der Alluvialebene.
Hauptschüttungsachsen existierten nördlich und südlich des Agrilovouni. Bis etwa zum
Ende der Römerzeit überwog die Sedimentanlieferung den eustatischen Meeresspiegelanstieg und die tektonische Subsidenz und bewirkte einen mehr oder weniger stetigen Küstenvorbau. In der Literatur vorliegende paläogeographische Szenarien, die in historischer Zeit von einer maximalen Transgression ausgehen, konnten somit widerlegt werden.
In jüngster Zeit ist in weiten Teilen des Arbeitsgebietes eine landwärtige
Verschiebung der Küstenlinie zu beobachten. Diese Tendenz wird im südlichen Bereich
der Alluvialebene dadurch beschleunigt, dass seit dem Bau des Kanals durch den
Paleoavli-Hügelzug weniger Sedimenteintrag erfolgt und somit die fluviale Aufhöhung
der Geländeoberfläche nachlässt.
Bei konstanten hydrologischen, klimatischen und tektonischen Bedingungen ist
mit fortschreitender Transgression zu rechnen. Hieraus ergibt sich die raumplanerische
Empfehlung, für künftige Bauvorhaben sowohl unmittelbare Küstennähe als auch das
Umfeld der tief liegenden Marschgebiete zu meiden. Langfristig muss entweder an eine
Befestigung der Küste oder an eine Aufgabe bisheriger Nutzflächen gedacht werden.
______________________________________________________________________________________
Summary
The coastal plain of Boukka is located at the eastern edge of the Amvrakikos Gulf in
northwestern Greece. Eight vibracores were sunk in order to decipher the stratigraphical,
geochemical, and faunistical information stored in this geoarchive. By means of
palaeogeographic methods (cf. chapter 6) the Holocene landscape change was
reconstructed (cf. chapter 7 and 8).
The results show an ingress of the Ionian Sea into the Amvrakikos Basin
significantly before 5000 cal BC. Since then, the relative sea level in the eastern part of
the gulf has risen continuously, showing its Holocene maximum at present. Based on
the available data, a differentiation between the influencing factors (climate, men,
tectonics, sediment charge) cannot be deduced.
By means of geochronological data from the northwestern part of the Amvrakikos
Gulf a strong tectonic subsidence is documented. The eastern edge of the gulf subsided
between 5000 and 1000 cal BC at an average rate of 1,43 m per millennium as
compared to its northwestern part, which was possibly even affected by uplifting during
that time. Subsequently, similar tectonic subsidence took place in both areas. This
change is attributed to an alteration of the local tectonic processes.
Increased average sedimentation rates could be proven for the southern part of the
coastal plain in the Neolithic period and since classical Antiquity. In contrast to this, the
values in the northern part have been declining since Chalcolithic times. Even though
different phases of increased fluvial sediment charge from the mountains could be
derived from the sediment cores, their chronostratigraphic classification is only
estimated due to the lack of appropriate datings. As for the question whether climatic
influence or human impact was mainly responsible for the increased erosion, explicit
conclusions cannot be drawn.
Concerning the Holocene development of the coastal plain, the hill Agrilovouni at
the western edge of the plain has most likely never been an island. At the time of the
Peloponnesian War, shallow lakes existed east of the hill whereas river beds were to be
found to the north and to the south of it. If this hill actually was the place of the ancient
site of Olpai (a federal court, cf. chapter 3), the wetland might have caused problems to
reach the place – particularly in the rainy season. The lagoon in the north is supposed to
have been enlarged between 1500 and 500 cal BC due to the accumulation or rather
relocation of sand spits. In the southern part of the coastal plain, yet another lagoon
existed for a long time. After 1945 it was finally silted up with fluvial sediments.
Periodic fluvial sediment load is the determining factor controlling the Holocene
evolution of the study area. The palaeogeographic results indicate several shiftings of
the riverbeds. The main fluvial axes proceeded to the north and to the south of the
Agrilovouni. Approximately until the end of the Roman period, sediment charge
outweighed the eustatic sea level rise and the tectonic subsidence, resulting in a
continuous prograding of the shoreline. Consequently, palaeogeographic scenarios based
on literary evidence, assuming the maximum transgression during Antiquity, could be
disproved.
In recent times a landward shifting of the coastline is observed for large parts of
the study area. This trend is even accelerated in the southern plain because of reduced
sediment supply since the digging of a new canal through the Paleoavli ridge.
Considering hydrological, climatic, and tectonic conditions to be constant, a
proceeding transgression has to be expected. Hence, both the direct proximity of the
coastline and the surroundings of the marsh areas should be avoided as building land. At
long sight, it should be thought about either a shoreline stabilisation or an abandonment
of the agriculturally used areas.
__________________________________________________________________________________
Σύνοψη
Θέµα της ∆ιπλωµατικής εργασίας: Η Εξέλιξη των Ακτών της Μπούκας στον
Αµβρακικό Κόλπο κατά την ολόκαινη περίοδο. – Μια συµβολή στην Παλαιογεωγραφία
της Ακαρνανίας (Βορειοδυτική Ελλάδα).
Οι Ακτές της Μπούκας βρίσκονται στο ανατολικό άκρο του Αµβρακικού Κόλπου
στην Βορειοδυτική Ελλάδα. Με την βοήθεια παλαιογεωγραφικών µεθόδων (Κεφάλαιο
5) αναπαραστάθηκε η δηµιουργία του τοπίου κατά την ολόκαινη περίοδο (Κεφάλαια 6
και 7).
Τα αποτελέσµατα αποδεικνύουν οτι το Ιόνιο Πέλαγος ήταν ενσωµατωµένο στην
Αµβρακική λεκάνη ήδη και εµφανώς πριν το 5000 π.Χ. Η σχετική επιφάνεια της
θάλασσας στο ανατολοκό άκρο του Κόλπου ανυψωνόταν έκτοτε συνεχώς και σήµερα
διατηρεί το επίπεδο στο οποίο είχε φτάσει στην διάρκεια της ολόκαινης περιόδου. Εξ
αιτίας της σηµερινής έλλειψης δεδοµένων, δεν είναι δυνατόν να διαχωριστούν οι
παράγοντες που επέδρασαν σ’αυτό (αν πρόκειται δηλ. για το κλίµα, την τεκτονική
δραστηριότητα, τις προσχώσεις ή τον άνθρωπο). Ωστόσο έγινε δυνατόν, µε την βοήθεια σύγκρισης δεδοµένων από την περιοχή των βορείων ακτών του Αµβρακικού κόλπου, να αποδειχτεί µια ισχυρή τεκτονική καθίζηση. Το ανατολικό άκρο του κόλπου υπέστη καθίζηση µεταξύ των ετών 5000 και 1000 π.Χ. σε σχέση µε το βόρειο άκρο, το οποίο µε τη σειρά του και στο ίδιο χρονικό διάστηµα προφανώς ανυψώθηκε 1,43 µέτρα κατά µέσο όρο ανά χιλιοτηρίδα. Ακολούθως η τεκτονική κίνηση συνεχίστηκε µε όµοιο τρόπο και στις δύο εξεταζόµενες περιοχές. Αυτό θα πρέπει να αποδοθεί σε µια µεταλλαγή της τοπικής τεκτονικής διαδικασίας.
Οσον αφορά στη νότια ακτή κατέστη δυνατόν να επαληθευτούν αυξηµένα
ποσοστά ιζηµάτων κατά την Νεολιθική εποχή και κατά την εποχή από την την Κλασική
αρχαιότητα, ενώ οι τιµές στο βόρειο τµήµα εµφανίζουν από την εποχή του Χαλκού
οπισθοχώρηση. Φάσεις αυξηµένης ποτάµιας απόθεσης από την ορεινή περιοχή είναι,
όσον αφορά στον ιζηµατικό πυρήνα ανιχνεύσιµες, ωστόσο όµως η χρονική ταξινόµηση
υπολογίστηκε ως επί το πλείστον χοντρικά εξαιτίας της απουσίας χρονολογήσεων.
Μονοσήµαντα συµπεράσµατα για το αν δηλ. πρόκειται για ανθρωπογενή ή κλιµατική
επίδραση κατά προτεραιότητα, για την ενισχυµένη διάβρωση δεν µπορούν να εξαχθούν.
Σ’ό,τι αφορά στην εξέλιξη των παραλίων µπορούµε να συµπεράνουµε, οτι ο
λόφος Αγριλοβούνι στο δυτικό άκρο του κάµπου δεν αποτέλεσε ποτέ στην χρονική
διάρκεια που εξετάζεται µία νήσο. Στην περίοδο του Πελοποννησιακού Πολέµου
υπήρχαν ανατολικά του λόφου αβαθείς λίµνες, ενώ βόρεια και νότια συνέρρεαν κοίτες
ρευµάτων. Αν πράγµατι τοποθετείται εδώ το αρχαίο οχυρό των Όλπων (Κεφάλαιο 3),
αυτό είναι αδύνατον να προσεγγιζόταν τουλάχιστον τους χειµερινούς µήνες µε στεγνά
πόδια. Η βόρεια λιµνοθάλασσα µεγάλωσε αισθητά προφανώς µεταξύ 1500 και 500 π.Χ.
λόγω της ανύψωσης αµµολωρίδων. Στο νότιο τµήµα των ακτών υπήρχε επίσης για
µεγάλο χρονικό διάστηµα µια λιµνοθάλασσα, που γέµισε οριστικά µετά το 1945 από
ιζήµατα του ρέµατος.
Οι ποτάµιες προσχώσεις είναι ο αποφασιστικός παράγοντας που δηµιούργησε το
τοπίο στη διάρκεια της ολόκαινης περιόδου στην εξεταζόµενη περιοχή. Οι έρευνες
έφεραν στο φως διάφορα σηµεία αποθέσειων κατά την ροή του ρέµατος εντός των
αλλουβιακών εκτάσεων. Αξονες της κυρίως πρόσχωσης υπήρχαν βόρεια και νότια του
Αγριλοβουνίου. Μέχρι περίπου το τέλος της ρωµαικής εποχής η µεταφορά ιζηµάτων
υπερέβαινε την ευστατική άνοδο της επιφάνειας της θαλάσσης και την τεκτονική
καθίζηση και συνέτεινε σταθερά και διαρκώς στη δηµιουργία ενός λίγο-πολύ σταθερού
αναχώµατος. Ετσι, τα υπάρχοντα στην βιβλιογραφία παλαιογεωγραφικά σενάρια, που
µιλούν για µια µέγιστη πληµµύρα στην ιστορική περίοδο, µπόρεσαν να ανασκευαστούν.
Στους νεότερους χρόνους παρατηρούµε σε µεγάλα τµήµατα της εξεταζόµενης
περιοχής µια οπισθοχώρηση της γραµµής των ακτών προς τα ηπειρωτικά. Αυτή η τάση
επιταχύνεται στο νότιο τµήµα των αλλουβιανών εκτάσεων από την κατασκευή της
διώρυγας Παλιαυλή-Λόφος, που έχει ως συνέπεια την µικρότερη µεταφορά και
απόθεση ιζηµάτων και ως εκ τούτου την υποχώρηση της ανύψωσης της επιφάνειας του εδάφους.
Κάτω από την διαρκή επίδραση υδρολογικών, κλιµατικών και τεκτονικών
συνθηκών θα πρέπει να υπολογίζεται το προοδευτικό πληµµύρισµα. Ως εκ τούτου
προκύπτει η χωροσχεδιαστική σύσταση, για µελλοντική αποφυγή οικοδόµησης τόσο
κοντά στις ακτές, όσο και σε µικρή απόσταση από αυτές. Μακροπρόθεσµα θα πρέπει να αποτελέσει αντικείµενο σκέψης, είτε η κατασκευή αναχωµατικών έργων στις ακτές, είτε η εγκατάλειψη των µέχρι σήµερα χρησιµοποιούµενων χώρων.
This chapter deals with human‐induced land degradation in the Ancient Near East and the human influences on landscape change. It provides a paleoclimatic background of the region and discusses deforestation and alteration of vegetation cover in the Near East, which was due mainly to the increasing need for wood and the expansion of farming and pastoral activities. Overgrazing became one of the most destructive forms of land degradation, and the impact of humans on wildlife can be assessed through the record of extinctions and the reduction of species, caused mainly by hunting. Another form of land degradation in the Near East was soil erosion. The worst cases of soil salinization in the Ancient Near East occurred in large‐scale irrigation systems, especially in the Mesopotamian lowlands, where irrigation was difficult and challenging.
The high sedimentation rate and shallow-water depositional depth of the sediments at site DP 30 in the Gulf of Taranto (central Mediterranean) provide unique biogenic signals that are usually not preserved in deeper records. This permits the reconstruction of long and short-term surface water modifications across the sapropel S1 period (10–6.5 ka), including calcareous nannofossil data at centennial-scale resolution.
The peculiar patterns of key taxa allowed the recognition of distinct long to short-term surface water changes that provide valuable evidence on climate conditions leading to sapropel deposition. As a long-term pattern, S1 is marked by a distinct increase of Helicosphaera carteri, thought to reflect increased detrital input/land-derived nutrients in the surface water, related to a higher influence of the Western Adriatic Current. A concomitant pattern of increased black organic particles in the sediments supports a connection between organic matter preservation at the seafloor and nutrient availability in the surface water. Decreased salinity in the surface water, testified by an increase of Braurudosphaera bigelowii, develops from 9.2 up to 6.5 ka.
At higher frequencies, additional changes occurred in surface-subsurface waters during the formation of S1 at shallow depths. Starting from 11 ka, the relative abundance pattern of Florisphaera profunda indicates a gradual nutrient enrichment in the subsurface waters and the development of a deep chlorophyll maximum (DCM), which becomes well established at the onset of sapropel S1, between 10 and 9 ka. A further change in the plankton ecosystem occurs between 9 and 8.2 ka, when reduced coccolithophore production is concomitant with diatom occurrence and enhanced Br/Ti level, implying a productivity increase. From 8 to 6.5 ka, coccolithophore productivity is re-established in relation to a reduction both in surface-water stratification and turbidity/nutrient availability, characterizing the final phase of sapropel formation. The turbidity in the surface waters was briefly reduced at 8.2 and 7.3 ka, when also oxygen conditions at the seafloor improved. A centennial variability in turbidity/low light conditions in surface waters is evident across S1 and is illustrated by the abundance patterns of H. carteri and Gladiolithus flabellatus. The occurrence of ascidian spicules also represents a distinct biotic signal across the S1 layer, indicating an increase of shallow-water biogenic carbonate or an aragonitic near-coastal source. Surface-water modifications at longer and shorter time scales, accompanying the deposition of sapropel S1 in the Gulf of Taranto, occurred nearly simultaneously and with a magnitude that is comparable to changes observed in S1 deposits in the central and eastern Mediterranean basin and slope settings.
The mineralogical, grain size and geochemical properties (e.g., Nd and Sr isotopes, Mg/Al ratios) of fine detritus that accumulated in the Dead Sea during the late Glacial to early Holocene time (∼22–7 ka) are used to identify its sources and modes of transport and to reconstruct the hydroclimate conditions in the Dead Sea watershed. Samples were retrieved from the DSDDP -5017-1A core that was drilled in the deep floor of the lake, and from various exposures of surface cover in the lake's watershed. The data show that during most of the late glacial, detrital particles were either directly blown mostly from the north Sahara Desert or were washed from the surface cover (loessial soils) of the north Negev Desert and Judea Desert. This picture changed during the end of the last glacial to the early Holocene (∼14 - 7 ka) when the fine detritus showed evidence for contribution from surface cover that contained basaltic soils. The contribution of basaltic soils to the fine detritus inventory of the Dead Sea and to terraces in the Jordan Valley, indicates a period of intense erosion in the northern highlands of the Dead Sea watershed, at an interval that partly coincides with Sapropel S1. In contrast, during the last interglacial Sapropel S5, fine detritus was mostly mobilized to the lake from southern and eastern region of the watershed. The formation and accumulation of terraces from this basaltic-derived material could be an important factor in the establishment of early agriculture settlements in the Jordan Valley.
Here we investigate the processes leading to high organic content and high pollen concentration in pelagic marine sediments. Three marine cores near the base of the Nile River cone display the classical Quaternary sequence of sapropels and hemipelagic muds. Large variations in total pollen concentration, as well as in percentage composition of the pollen assemblage are clearly linked to the two lithological types. All pollen types have much higher concentration in sapropels than in muds, by 3 or 4 orders of magnitude. Within sapropels, the percentages of Gymnosperms (Pinus and Cedrus) pollen and Pteridophyte spores, are very low and pollen spectrum is dominated by various Angiosperms. These variations in total pollen concentration as well as in percentages cannot be accounted for by variations in pollen production, or in efficiency of transport, because they similarly involve pollen of different areas and climates, transported to the sea by different means. The cause for these variations can only be a difference in preservation of pollen. Preservation is good in sappropels for all pollen types, but generally poor in muds. We believe that sapropels were deposited under reducing bottom waters which allowed a better preservation of the organic matter including pollen.
Under modern conditions, the reoxygenation of eastern Mediterranean deep
water is the result of the formation of dense bottom water in the
southern Adriatic Sea. Oxygen isotopic records of planktonic foraminfera
used as a paleosalinity tracer show that Po River and/or the alpine
glaciers meltwater are not directly responsible of the inhibition of the
deep water formation in the Adriatic, during sapropel (S1) formation at
9,000 years B.P.. Sedimentological evidence indicates that fully
oxygenated conditions in the deep Adriatic occurred only by
1,650±100 years B.P., a long time after the total reoxygenation
of the deep eastern Mediterranean. Organic carbon content and isotopic
ratio indicate that persistence of a reduced sediment phase until 1,650
years B.P., does not result from increased primary productivity or large
input of terrestrial organic matter.
THE warming at the end of the last glaciation was characterized by a
series of abrupt returns to glacial climate, the best-known of which is
the Younger Dryas event1. Despite much study of the causes of
this event and the mechanisms by which it ended, many questions remain
unresolved1. Oxygen isotope data from Greenland ice
cores2-4 suggest that the Younger Dryas ended abruptly, over
a period of about 50 years; dust concentrations2,4 in these
cores show an even more rapid transition (<~20 years). This extremely
short timescale places severe constraints on the mechanisms underlying
the transition. But dust concentrations can reflect subtle changes in
atmospheric circulation, which need not be associated with a large
change in climate. Here we present results from a new Greenland ice core
(GISP2) showing that snow accumulation doubled rapidly from the Younger
Dryas event to the subsequent Preboreal interval, possibly in one to
three years. We also find that the accumulation-rate change from the
Oldest Dryas to the Bø11ing/Allerød warm period was large
and abrupt. The extreme rapidity of these changes in a variable that
directly represents regional climate implies that the events at the end
of the last glaciation may have been responses to some kind of threshold
or trigger in the North Atlantic climate system.
The early village of Abu Hureyra is significant because of its great size ( ca. 11.5 ha) and long sequence of occupation ( ca. 11,500–7000 bp) that spans the transition from late Pleistocene hunting and gathering to early Holocene farming, and the cultural change from Epipaleolithic to Neolithic. The 40 accelerator dates obtained for Abu Hureyra provide new information on the development of agriculture in Southwest Asia. The dates have demonstrated that the site was inhabited for much longer than the few conventional radiocarbon dates for the site had suggested. The gap between the Epipaleolithic and Neolithic villages seems to have been brief. A change in climate and vegetation, dated at ca. 10,600 BP, during the span of occupation of the Epipaleolithic village, precipitated an adjustment in the foraging way of life of its inhabitants just before the inception of agriculture. Dating of individual bones and seeds has shown that the wild progenitors of sheep and several cereals were present near Abu Hureyra in the late Pleistocene and early Holocene, well outside their present areas of distribution. This has implications for where those species may have been domesticated. A rapid switch from exploitation of the gazelle to herding of sheep and goats during the Neolithic occupation occurred ca. 8300 bp.
The Younger Dryas, defined in NW Europe by a characteristic pollen zone, is more difficult to trace in pollen sequences of the eastern Mediterranean or the Near East. The presence or absence of this period in the form of a pollen zone and/or chrono-zone will be discussed for the area between northern Greece in the west, and the Iranian plateau in the east. The Quaternary vegetation history of this area is relatively well studied from about 50 pollen diagrams. However, only 17 sites have a pollen record that includes the Late Glacial period. Only part of these sites display a pollen zone that fits the description of the European Younger Dryas and indeed is dated to the period. Diagrams from other sites so far do not show a pollen sequence that allows a Younger Dryas zonation. -from Author
- The present approach to the Late Quaternary climate history of the Eastern Mediterranean and the Near East involves a re-evaluation of the chronologies of some selected published pollen diagrams in Greece and Syria, based on the assumption that particularly similar pollen spectra are synchronous. The absolute chronology is based on AMS (Accelerator Mass Spectrometry) dates of a marine core in the Adriatic Sea, for which the pollen diagram can be correlated with those of eastern Greece. The succession of two marker events is widely observed : a phase where the herbaceous pollen abundance, mainly Chenopodiaceae, is the highest ever for the Late Quaternary, identified as the global Younger Dryas, dated 11,000-10,000 yr B.P., and a phase of Pistacia pollen presence from 9,000 to 6,000 yr B.P.. The abundance of Pistacia pollen is maximum from 9,000 to approximately 8,000 or 7,500 yr B.P.. The abundance of deciduous oak pollen rises from nil or very little after 10,000 yr B.P., and peaks with that of Pistacia.. The latter then vanishes for a few hundred years, and reappears with lower values until 6,000 yr B.P.. After 6,500 yr B.P., other deciduous trees display maximum pollen abundance. The Younger Dryas is interpreted as very arid and cold, the phase of rising oak abundance at the beginning of the Holocene as increasingly humid, with summer moisture, and warmer, and the Pistacia maximum phase as a climate optimum with the mildest, frost-free winters. The other deciduous trees indicate still abundant precipitation, including in summer, but generally cooler winters. This vegetational and climatic evolution concerns the northern and eastern borderlands of the Eastern Mediterranean. The comparison with that of neighbouring lands and seas precludes the possibility that any area of the Near East could have a completely opposite climate history.
We present new evidence suggesting that the Late Glacial worldwide episode of cooling known as the Younger Dryas (ca. 11,000-10,000 B.P.) had a significant impact on climate, vegetation, and human economy in southwest Asia. In the Levant a new pollen core extracted from Lake Huleh and plant remains from the early village of Abu Hureyra 1 indicate that forest gave way to steppe in response to the onset of drier climatic conditions contemporary with the Younger Dryas. Similar effects may be seen in pollen cores from elsewhere in southwest Asia. This alteration in climate and vegetation obliged the inhabitants of Abu Hureyra to modify their plant gathering, and led to significant disruptions in culture and settlement over a wide area. We argue that the stresses induced by these events were a contributing factor in the subsequent development of agriculture in southwest Asia.
The early village of Abu Hureyra is significant because of its great size (ca. 11.5 ha) and long sequence of occupation (ca. 11,500-7000 BP) that spans the transition from late Pleistocene hunting and gathering to early Holocene farming, and the cultural change from Epipaleolithic to Neolithic. The 40 accelerator dates obtained for Abu Hureyra provide new information on the development of agriculture in Southwest Asia. The dates have demonstrated that the site was inhabited for much longer than the few conventional radiocarbon dates for the site had suggested. The gap between the Epipaleolithic and Neolithic villages seems to have been brief. A change in climate and vegetation, dated at ca. 10,600 BP, during the span of occupation of the Epipaleolithic village, precipitated an adjustment in the foraging way of life of its inhabitants just before the inception of agriculture. Dating of individual bones and seeds has shown that the wild progenitors of sheep and several cereals were present near Abu Hureyra in the late Pleistocene and early Holocene, well outside their present areas of distribution. This has implications for where those species may have been domesticated. A rapid switch from exploitation of the gazelle to herding of sheep and goats during the Neolithic occupation occurred ca. 8300 BP.
La paléoclimatologie du domaine continental qui s'étend de la Méditerranée Orientale à l'Océan Indien est retracée par la comparaison des séries palynologiques issues de sites continentaux et marins. Les derniers sont datés par référence à la variation du volume global des glaces, décrite par la variation de l'oxygène isotopique 18 par rapport à l'oxygène 16 dans les tests de foraminifères marins. Pour celle-ci, une chronologie a été élaborée par de nombreuses mesures radiométriques dans un grand nombre de sites marins, appuyées par la chronologie astronomique de la variation des éléments de l'orbite terrestre.
La succession pollinique dans les sites marins de Méditerranée pour le Tardiglaciaire et le début de l'Holocène est très typée. Elle se signale par une phase très aride et froide (pollens de Chénopodiacées abondants) identifiée comme Dry as Récent, datée (I4C) 11 000-10 000 BP, suivie par une rapide expansion de l'abondance des pollens d'arbres tempérés décidus, principalement le Chêne, et surtout par l'apparition de pollens de Pistachier qui persistent de 9 000 à 6 000 BP lors de la première moitié de l'Holocène, et révèlent une phase d'optimum climatique avec des hivers doux et des étés sans sécheresse.
Comme cette succession est repérée dans tous les diagrammes polliniques des sites continentaux de Grèce, Turquie et Iran occidental, on infère que la circulation atmosphérique générale et régionale impose le synchronisme respectif de ces phases polliniques. La chronologie marine est alors appliquée aux séries polliniques continentales, quelle que soit la chronologie propre à chacun des sites, basée sur quelques datations radiométriques. Cette technique fait apparaître des réajustements, variables selon les sites. Son intérêt est de permettre, sur ces bases, de proposer une chronologie pour de nouveaux sites où est identifiée la même succession pollinique. Le Maximum glaciaire est la dernière phase froide d'une certaine durée précédant le Dryas récent et, en général, apparaît comme moins aride que ce dernier.
Continuous pollen and isotopic records were established for core BAN 84 09 GC retrieved from the anoxic Bannock Basin in the Eastern Mediterranean. On the basis of two 14C dates, they document the palaeoclimate between about 25.7 ka B.P. and 5.2 ka B.P. in the northern borderlands of the Ionian Basin. The upper half of the core has been redeposited.The isotopic record displays a correlation with pollen percentages that is strong and positive for Artemisia (sage-brush) and negative for Quercus (oak). The last glacial maximum and the deglaciation are identified by these combined taxa, together with Chenopodiaceae. The glacial maximum around 18 ka B.P. (which has elsewhere been dated from 20 to 15 ka B.P.) has pollen percentages that are high for Artemisia and low for Quercus. The climate in the pollen source area was arid, cold in winter, briefly warm in summer and sustained the vegetation of a semi-desert. The onset of deglaciation after 18 ka B.P. coincides with that of the decline in Artemisia pollen percentage. However, this decline does not indicate reduced aridity, because it is accompanied by a pollen percentage rise of the even more arid herbs Chenopodiaceae and Ephedra. Throughout the deglaciation from 18 to 11 ka B.P., the aridity progressively increases, culminating at 11 ka B.P. This trend is briefly interrupted by a more humid event, shown by a peak in Artemisia pollen percentage and a smaller peak in oak; these two peaks are coeval with the Bölling-Alleröd chronozone (13-11 ka B.P.). Maximum aridity occurs during the Younger Dryas chronozone (11-10 ka B.P.). Afterwards, the oak pollen percentage begins a steady increase, and its maximum value is coeval with the lowest isotopic value, dated at 8760 ± 170 yr B.P. This period was one of high moisture, warm summers, and, according to altitude, mild to cool winters. This climate sustained forests that were Mediterranean in the lowlands and warm temperate in the uplands. A high pollen concentration is observed during this period and reveals the presence of sapropel S1, which is otherwise unrecognizable in this entirely black core. During the following period between 8760 ± 170 and 5200 yr B.P., the δ180 reverts to slightly higher values and the Quercus pollen percentage decreases, while the pollen percentage of the wetter Ostrya, the oriental hornbeam, increases. The high pollen concentration during the deposition of sapropel S1 cannot have been caused by increased pollen input into the sea, this pollen being wind-borne, nor by increased pollen production for all taxa, both trees and herbs. We conclude that it is entirely due to increased preservation of this allochtonous organic material by the deep anoxia of the bottom water, below a thick anoxic water column. The coincidence of sapropel deposition with warm and humid local climate as well as with the second global meltwater pulse suggests that the cessation of bottom-water ventilation was due to decreased surface water density, resulting from less saline incoming Atlantic surface water, increased local runoff, and warmer winters.
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.
Pollen spectra from three eastern Mediterranean cores have been used to document the paleoclimates of the Levantine Basin borderlands over the last 25O kyr to establish the relationship between this regional climate data set and the global climates as recorded by foraminiferal delta18O and to compare it with proximal land pollen records. Core MD 84642 with eight sapropels covers the last two climatic cycles up to the early Holocene, MD 84627 with four sapropels goes back to 125 kyr, and MD 84629 with one sapropel covers the last 70 kyr. The sedimentation rate decreases from core 629, located at the shallowest depth beneath the Nile River plume, to cores 627 and 642. During the interglacials defined by a low 18O/16O ratio, the abundance of tree pollen is maximum and points to an optimum Mediterranean climate with greatest humidity, including some summer rainfall. During glacial maxima, with highest 18O/16O ratio, the pollen abundance is high for steppe and semidesert plants and low for trees, indicating a definitely more arid, more continental, and probably colder climate. The variations of pollen abundance occur in phase with those of the foraminifer delta18O record. This signifies that the regional climate of the Levantine Basin borderlands has the same temporal pattern as the global ice volume documented by the ice volume curve.
If we accept the evidence at face value, we are led to conclude that emmer was probably domesticated in the upper Jordan watershed and that einkorn was domesticated in southeast Turkey. Barley could have been domesticated almost anywhere within the arc bordering the fertile crescent. All three cereals may well have been harvested in the wild state throughout their regions of adaptation long before actual farming began. The primary habitats for barley, however, are not the same as those for the wheats. Wild barley is more xerophytic and extends farther downslope and into the steppes and deserts along the wadis. It seems likely that, while all three early cereals were domesticated within an are flanking the fertile crescent, each was domesticated in a different subregion of the zone.
Lest anyone should be led to think the problem is solved, we wish to close with a caveat. Domestication may not have taken place where the wild cereals were most abundant. Why should anyone cultivate a cereal where natural stands are as dense as a cultivated field? If wild cereal grasses can be harvested in unlimited quantities, why should anyone bother to till the soil and plant the seed? We suspect that we shall find, when the full story is unfolded, that here and there harvesting of wild cereals lingered on long after some people had learned to farm, and that farming itself may have originated in areas adjacent to, rather than in, the regions of greatest abundance of wild cereals.
We need far more specific information on the climate during incipient domestication and many more carefully conducted excavations of sites in the appropriate time range. The problem is far from solved, but some knowledge of the present distribution of the wild forms should be helpful.
Pale´ de la Mediterranee orientale et de l'Asie du sud-ouest de 15000 d 6000 BP After the deluge: Mediterranean stagnation and sapropel formation Vegetation dynamics and climate during the deglaciation in the south Adriatic basin from a marine record
- Rossignol
- M M Strick
- W Nesteroff
- P Olive
- C Grazzini
Rossignol-Strick, M. (1997). Pale´ de la Mediterranee orientale et de l'Asie du sud-ouest de 15000 d 6000 BP. Pateonent, 23, 175—186. Rossignol-Strick, M., Nesteroff, W., Olive, P., & Vergnaud-Grazzini, C. (1982). After the deluge: Mediterranean stagnation and sapropel formation. Nature, 295, 105—110. Rossignol-Strick, M., Planchais, N., & Paterne, M. (1992). Vegetation dynamics and climate during the deglaciation in the south Adriatic basin from a marine record. Quaternary Science Review, 11, 415—423.
Redistribution and geo-chemical behaviour of redox-sensitive elements around S1, the most recent eastern Mediterranean sapropel The floral record of the late Cenozoic in Europe
- J Thomson
- N C Higgs
- T R S Wilson
- I W Croudace
- G J Lange
- P J M T Sandvoort
- T A Wijmstra
- W H Zagwijn
Thomson, J., Higgs, N. C., Wilson, T. R. S., Croudace, I. W., de Lange, G. J., & van Sandvoort, P. J. M. (1995). Redistribution and geo-chemical behaviour of redox-sensitive elements around S1, the most recent eastern Mediterranean sapropel. Geochimica et Cosmochimica Acta., 59, 3487—3501. van der Hammen, T., Wijmstra, T. A., Zagwijn, W. H. (1971). The floral record of the late Cenozoic in Europe. In K. K. Turekian (Ed.), ¹he Cenozoic Glacial Ages. (pp. 391—424). New Haven: Yale Univerity Press. van Zeist, W., & Bottema, S. (1991). ¸ate Quaternary vegetation of theNear East. TAVO Beihefte Reihe A 18, Dr Ludwig Reichert Verlag, Wiesbaden.