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his chapter considers applications of micro-XRF scanning in fluvial depositional environments and presents case-studies from Britain and Ireland in three key river management areas: flood reconstruction; pollution and provenance mapping; and floodplain sediment dynamics. Although fluvial sediment archives are typically shorter and more fragmented t...
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... in non-tidal rivers and estuaries have been widely researched and documented by fluvial geomorphologists and coastal scientists, respectively. However, relatively little geomorphological- geochemical research has been undertaken in tidally-influenced river reaches despite their obvious vul- nerability to the effects of climate and sea-level change. Sediment cores, ranging from 2 to 5 m in length, were recovered from 18 sites in the downstream part of the Dyfi River that is still under tidal influence (Fig. 8.7). Organic material present in the cores was 14 C dated and the cores were Itrax-scanned at either 0.5 mm (silt and clay-rich sediments) or 1.0 mm (sand-rich sediments) resolution. Data are presented here for site 1 (cores 1.2 and 1.3) at Machynlleth upstream of the normal tidal limit and for site 4 (cores 4.1 and 4.3) at Dyfi Junction at the head of the Dyfi ...
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... Flüvyal ortamlarda taşkın ovası sedimanları yüksek K oranı ve yüksek Si/Ti oranını ile karakterize edilmektedir. Ayrıca bu çevrelerde Zr/Rb oranının yüksek olması kaba taneli sediman taşınımını (akarsu yatağını) yansıtmaktadır (Turner, Jones, Brewer, Macklin ve Rassner, 2015). Bununla birlikte arkeolojik materyalin olduğu kültür katmanı seviyelerinde ise sediman içindeki TOC, Sr ve Fe konsanstrasyonu artmaktadır. ...
Gözlükule Mound is located in the northern Tarsus Plain . This study aims to reconstruct the paleoenvironment of Gözlükule Mound and the paleogeographic development of the Tarsus Plain. Core sediments taken from 19 drillings made between 2001-2002 are used to reveal the effects of natural environmental changes, with granulometric analyses, elemental analyses, and paleontological analyses being done for this purpose. In light of these analyses, the study interprets the natural environmental changes to the Tarsus Plain and the surroundings of Gözlükule Mound that occurred in the Holocene. In order to connect these developments to a certain chronology, a total of five radiocarbon-14 analyses were made with the support of Ege University Scientific Research Project Nos. SHD-2021-22452 and SYL-2020-22305. The paleontological, sedimentological, and elemental analyses, as well as the dating results of the sediment samples, were reevaluated, with the paleogeographic development of the region being revealed in accordance with the new data. ---------------- Gözlükule Höyüğü, günümüzdeki Tarsus (Berdan) Ovası’nın kuzey kenarında bulunmaktadır. Bu çalışmada, Tarsus Ovası’nın paleocoğrafik gelişimini ve bölgede yer alan Gözlükule Höyüğü’nün doğal çevre değişimlerinden nasıl etkilendiğini ortaya koymak amacıyla, 2001 ve 2002 yıllarında yörede yapılmış olan 19 adet delgi sondaja ait sedimanlar yeni analizler ışığında değerlendirilmiştir. Sedimanlar, granülometrik, element özellikleri ve paleontolojik açıdan analiz edilmiştir. Bu analizlerin sonuçlarına göre Tarsus Ovası ile Gözlükule Höyüğü çevresinin Holosen’deki doğal çevre değişmeleri yorumlanmıştır. Bu gelişmelerin belli bir kronolojiye bağlanabilmesi için Ege Üniversitesi Bilimsel Araştırma Projeleri SHD - 2021 - 22452 ve SYL - 2020 - 22305 numaralı iki proje desteği ile toplam 5 adet RC14 analizi yaptırılmıştır. Sediman örnekleri paleontolojik, sedimantolojik, element analizleri ve tarihleme sonuçları birlikte değerlendirilerek yeni verilere göre yörenin paleocoğrafik gelişimi ortaya konmuştur.
... The geochemical dataset provided by X-ray fluorescence (XRF) spectrometry facilitates a high-resolution geochemical profile and provides a rapid, nondestructive method for providing a continuous, though less informative, grain size profile [7]. Various elemental ratios have been used as proxies to interpret grain-size changes in sediment sequences in fluvial and coastal studies [8]. Particular elements such as Zr, Rb, and Ti tend to align with specific grain-size fractions during transportation by water or wind, with Zr being associated with sand and coarse silt, while Rb primarily occurs with silt and clay-sized fractions [8]. ...
... Various elemental ratios have been used as proxies to interpret grain-size changes in sediment sequences in fluvial and coastal studies [8]. Particular elements such as Zr, Rb, and Ti tend to align with specific grain-size fractions during transportation by water or wind, with Zr being associated with sand and coarse silt, while Rb primarily occurs with silt and clay-sized fractions [8]. Here we present a novel empirical method whereby the mean grain size and textual definition can be estimated at every tested interval (every two cm through the length of the core in our case), based on a simple elemental ratio. ...
Three cores were taken along the salinity gradient (n-s) in the coastal wetlands of Louisiana; an intermediate marsh, a brackish marsh, and a mangrove swamp. The cores display remarkable stratigraphic and chronologic correlations, representing six successive ecosystems and environments, namely: interdistributary bay, freshwater marsh/swamp, deltaic lake, freshwater marsh/swamp, intermediate marsh, and brackish/saline. Sedimentary, geochemical, and palynological data were used to reconstruct the paleoenvironments, including ambient environment and ecosystem types. Concentrations of Ba and Br, along with six elemental ratios (Ca/Rb, Zr/Rb, Ti/Rb, K/Ti, Mn/Rb, S/Rb), were employed to infer proxies for a range of environmental conditions (waterlogging, redox levels), depositional processes (fluvial vs marine or in situ), and sediment characteristics (grain size). Correlating the identification of environment types, inferred depositional processes, and the known history of the Mississippi delta cycle with the ecosystem reconstruction provides insight into ecosystem response to a variety of stresses, which information can be used to better understand and predict present and future responses to the ongoing stresses. Additionally, a simple elemental ratio (Zr/Rb) was used to produce a continuous (2 cm resolution) estimate of grain size along the length of the cores. The close correlation between the estimated grain size and measured samples shows that this ratio is a valid method for quickly assessing rough grain size, and is especially useful for identifying sedimentary inflection points.
... The geochemical dataset provided by X-ray fluorescence (XRF) spectrometry facilitates a high-resolution geochemical profile and provides a rapid, nondestructive method for providing a continuous, though less informative, grain size profile [7]. Various elemental ratios have been used as proxies to interpret grain-size changes in sediment sequences in fluvial and coastal studies [8]. Particular elements such as Zr, Rb, and Ti tend to align with specific grain-size fractions during transportation by water or wind, with Zr being associated with sand and coarse silt, while Rb primarily occurs with silt and clay-sized fractions [8]. ...
... Various elemental ratios have been used as proxies to interpret grain-size changes in sediment sequences in fluvial and coastal studies [8]. Particular elements such as Zr, Rb, and Ti tend to align with specific grain-size fractions during transportation by water or wind, with Zr being associated with sand and coarse silt, while Rb primarily occurs with silt and clay-sized fractions [8]. Here we present a novel empirical method whereby the mean grain size and textual definition can be estimated at every tested interval (every two cm through the length of the core in our case), based on a simple elemental ratio. ...
Three cores were taken along the salinity gradient (n-s) in the coastal wetlands of Louisiana; an intermediate marsh, a brackish marsh, and a mangrove swamp. The cores display remarkable stratigraphic and chronologic correlations, representing six successive ecosystems and environments , namely: interdistributary bay, freshwater marsh/swamp, deltaic lake, freshwater marsh/ swamp, intermediate marsh, and brackish/saline. Sedimentary, geochemical, and palynological data were used to reconstruct the paleoenvironments, including ambient environment and ecosystem types. Concentrations of Ba and Br, along with six elemental ratios (Ca/Rb, Zr/Rb, Ti/ Rb, K/Ti, Mn/Rb, S/Rb), were employed to infer proxies for a range of environmental conditions (waterlogging, redox levels), depositional processes (fluvial vs marine or in situ), and sediment characteristics (grain size). Correlating the identification of environment types, inferred deposi-tional processes, and the known history of the Mississippi delta cycle with the ecosystem reconstruction provides insight into ecosystem response to a variety of stresses, which information can be used to better understand and predict present and future responses to the ongoing stresses. Additionally, a simple elemental ratio (Zr/Rb) was used to produce a continuous (2 cm resolution) estimate of grain size along the length of the cores. The close correlation between the estimated grain size and measured samples shows that this ratio is a valid method for quickly assessing rough grain size, and is especially useful for identifying sedimentary inflection points.
... Multi element determination used an ITRAX XRF scanner (Croudace and Rothwell, 2015;Croudace et al., 2006) on sediment samples collected from 400 to 500 mm long 'u-channels', scanned at 2 mm resolution using 30 kV, 30 mA settings and a 15 s count time at the British Ocean Sediment Core Research Facility (BOSCORF), National Oceanography Centre, Southampton (NOCS). The use of XRF in fluvial landscapes has great potential to determine floodplain dynamics, depositional character and flood histories (Turner et al., 2015), and has already been used with success in the Severn catchment (Jones et al., 2010(Jones et al., , 2012Pears et al., 2020aPears et al., , 2020b. ITRAX XRF was used in this instance as a way of determining variations in the nature and composition of the visible lamination at a higher resolution than could be physically tested by grain size and the laser diffraction method. ...
The analysis of exceptionally well-preserved visible clastic laminations in deep alluvial sediments at Kempsey, Worcestershire (UK), allows a new high resolution analysis of late-Holocene flood-history in the largest UK catchment, as well as local human response. At the sample site over 4.5m of sandy-silt overbank-alluvium accumulated on the floodplain and optically stimulated luminescence (OSL) dating of the upper 2.25m demonstrates accretion from the late 14th century CE onwards. Sub-centimetre to centimetre resolution multi-proxy sediment analysis (loss on ignition, magnetic susceptibility, particle size, ITRAX and portable XRF) demonstrate clear variations in depositional history over the last millennium due to channel stability. Between c. 1380 and 1550CE overbank sedimentation was driven by lower energy flood events, with negligible effect from climatic conditions during the Spörer Minimum (1460–1550CE). After c. 1550CE the magnitude of flooding events increased and by c. 1610CE, the start of the visible sub-centimetre laminations, the
accumulation rate regularly exceeded 3mm year−1, which increased to 4.5mm year−1 between c. 1690 and 1710CE, and 3 and 3.5mm year−1 between c. 1790 and 1840CE before alluviation was altered by an embankment. The greatest extent of coarse overbank deposition and increased accumulation rate occur concurrently with periods of climatic instability associated with the Maunder (1645–1715CE) and Dalton (1790–1820CE) Minima, the periods of largest historical floods and during the intensification of arable cultivation across the middle Severn catchment. This data correlates well with other sites in the catchment suggesting that these are basin-wide forcing-responses. We also present evidence that this catchment-wide hydro-geomorphological history had local effects in shifting the geographical focus of an important settlement away from its historic floodplain edge location – which can be viewed as an adaptation to the flood risk.
... To account for variations in moisture content, surface roughness, and grain size, ITRAX data were normalized against the total counts per second (Ohlendorf at al., 2015). Si:Ti ratios are interpreted as a measurement of biogenic silica (Davies et al., 2015) and Si:Al ratios are used as proxies for grain size (Turner et al., 2015). The ratio of incoherent (inc) to coherent (coh) dispersion depends on the average atomic number of the sediment material (Rothwell and Rack, 2006), which generally correlates with organic carbon content (Burnett et al., 2011) because the organic elements have average atomic weights smaller than aluminosilicates or quartz. ...
There are very few records of past terrestrial environmental change of any time period for the Australian tropical savannas. Here we document the hydrological development of Sanamere Lagoon, north Queensland, from a 1.72 m sediment sequence with a basal age of ca. 33 ka. We measure a variety of proxies reflecting environmental change within and around the lagoon, including grain size, elemental and diatom abundance, and carbon and nitrogen isotope composition. By integrating the interpretation of multiple proxies, we show that regional climatic events, such as the reactivation of the monsoon at 15 ka and sea-level rise ending at 7 ka, are reflected in local ecosystem change and a diversity of biogeochemical responses in Sanamere Lagoon. This record makes a significant contribution to the development of records of environmental change from an under-studied region in tropical Australia through the Holocene to the LGM and beyond—a step towards enabling a more detailed understanding of regional monsoon (paleo)dynamics. In particular, this study highlights nuances in the effect of Indonesian-Australian Summer monsoon dynamics in a region less affected by sea level and continental shelf drowning complexities.
... Sediman tane boyu özelliklerini gösteren elementlerde Si, Ti, Zr ve Rb elementleri flüvyal ortamın belirlenmesinde önemlidir. Sözgelimi Si/Ti oranı sediman taşınımını ve Zr/Rb oranının yüksek olması taşınan sedimanın kaba taneli olduğunu anlatmaktadır (Turner et al., 2015). Ayrıca düşük Ca/Fe Ca/Al ve Ca/Ti oranları akarsu sedimanının varlığını açıklamaktadır (Pint et al., 2015;Elschner et al., 2021). ...
Tarsus Ovası Çukurova'nın bir parçasıdır ve güneyde Akdeniz; kuzey ve kuzeybatıda Bolkar Dağları; doğuda ise Misis Dağları ile sınırlandırılmış bir bölgede yer almaktadır. Döneminin en önemli yerleşmelerinden olan Gözlükule Höyüğü Tarsus Ovası'nda yer almaktadır. Neolitik dönemde önemli bir yerleşme merkezi olan höyük, kesintisiz yerleşime sahne olmuştur. "Tarsus Berdan Ovasında Paleocoğrafya ve Jeoarkeoloji Araştırmaları" adlı tez çalışmamız 6 bölümden oluşmaktadır. Giriş bölümünde çalışma alanının coğrafi konumu, amaç ve yöntem konuları üzerinde durulmuştur. Tezin ikinci ve üçüncü bölümlerinde Tarsus ve çevresinin fiziki coğrafya özellikleri ile arkeolojisi açıklanmıştır. Dördüncü bölümde Tarsus Ovası'ndan elde edilen sediman örnekleri üzerine uygulanan analizler ayrıntılı olarak belirtilmiştir. Çalışmanın beşinci bölümünde bölge paleocoğrafya-jeoarkeolojisi yeniden değerlendirilmiş, son bölümde ise çalışmanın nihai sonuçları verilmiştir. Çalışmada Tarsus Ovası'nda gerçekleştirilen delgi sondaj çalışmalarından elde edilen sediman örnekleri üzerinde ayrıntılı analizler gerçekleştirilmiştir. Farklı derinliklerden alınan 300 adet sediman örneğinin lazer kırınımlı tane boyu analizleri, 145 adet sediman örneğinin X-Işını Floresansı yöntemiyle element analizleri, Karbon-Nitrojen-Sülfür analizleri, Toplam Karbon ve Toplam İnorganik Karbon analizleri yapılmış, 140 adet sediman örneğinin de paleontolojik analizleri gerçekleştirilmiştir. Farklı derinliklere ait 5 kavkı örneğine Tübitak MAM tarafından Radyokarbon-14 tarihlendirmesi yapılmıştır. Bu analizler ışığında bölgenin paleocoğrafyasına yeni bilimsel katkılar sunulmuştur. Yapılan analizlerin sonuçlarına göre, Erken Holosen'de gerçekleşen transgresyonla kıyı çizgisi Tarsus Ovası'nın kuzeyine doğru sokulduğu ancak Gözlükule Höyüğü'ne kadar ulaşamadığı kanıtlanmıştır. Gözlükule Höyüğü'nün en az 5 kilometre kadar güneyinde bulunan kıyı çizgisi, Orta ve Geç Holosen'de bölgede yer alan Tarsus Çayı ile Seyhan ve Ceyhan Irmaklarının taşıdığı alüvyonlarla dolma sonucu, tekrar açığa doğru ilerlemiştir. Orta ve Geç Holosen'de gelişen süreçlere bağlı olarak, Gözlükule Höyüğü'nün güneyinde bir lagünün oluştuğu ispatlanmıştır. Sediman birikiminin sürmesiyle birlikte lagün ortamı giderek önce bir göle, daha sonrasında delta-taşkın ovasına dönüşmüştür. Günümüze kadar ova üzerinde bu süreçlerin izleri olarak kalan bataklıklar halindeki sulak alanlar da yapılan drenaj çalışmaları ile kurutulmuştur. Günümüzde Tarsus'un güneyinde küçük bir alan kaplayan Karabucak Bataklığı, bu ortamların son kalıntısıdır.
The Tarsus Plain is part of Çukurova and the Mediterranean Sea in the south; Bolkar Mountains to the north and northwest; It is located in a region bordered by Misis Mountains in the east. One of the most important settlements of its period, Gözlükule Mound is located on the Tarsus Plain. The mound, a significant settlement in the Neolithic period, has been inhabited uninterruptedly until today. Our thesis study called "Paleogeographical and Geoarchaeological Research in the Tarsus Berdan Plain" consists of 6 chapters. In the introduction, the geographical location of the study area, the aim, and the method have been emphasized. In the second and third chapters of the thesis, the physical geography and archeology of Tarsus and its surroundings have been explained. In the fourth chapter, the analyzes applied to the sediment samples obtained from the Tarsus Plain have been given in detail. In the fifth part of the study, the paleogeography-geoarchaeology of the region has been re-evaluated, and in the last sixth, the final results of the study have been explained. In this study, detailed analyzes have been made on the sediment samples obtained from the core drillings carried out in the Tarsus Plain. Laser diffraction grain size analysis of 300 sediment samples, XRF, CNS/CN elemental analysis of 145 sediment samples, and paleontological analysis of 140 sediment samples was carried out. Radiocarbon-14 dating has been made by Tübitak MAM on 5 shell samples of different depths. In the light of these analyzes, new scientific contributions to the paleogeography of the region have been explained. According to the results of the analysis, it has been proven that the shoreline was intruded towards the north of the Tarsus Plain due to the transgression that took place in the Early Holocene, however it could not reach as far as the Gözlükule Mound. The coastline, south of the Gözlükule Mound, has moved towards the open sea again due to filling with the alluvium carried by the Tarsus Stream and the Seyhan and Ceyhan Rivers in the region during the Middle and Late Holocene. It has been proven that a lagoon was formed in the south of Gözüle Mound due to the processes that developed in the Middle and Late Holocene. Because of continued sediment accumulation, the lagoon gradually turned into a lake and then a delta-flood plain. Wetlands in the form of swamps, which have remained as traces of these processes on the plain, have also been dried by the drainage works. The Karabucak Swamp, which occupies a small area in the south of Tarsus today, is the last remnant of these environments.
... Zr/Rb has been used as grain-size proxy in marine, lacustrine, and deltaic sediments (Turner et al., 2015), and is often used as a proxy for flood events, because Zr is abundant in coarse sediments (e.g., silt, sand) as a heavy mineral (e.g., zircon), while Rb is abundant in clays (Dypvik and Harris, 2001;Wang et al., 2011;Croudace and Rothwell, 2015). During riverine floods coarser sediments are transported basinwards, so higher values of Zr/Rb can be used for flood frequencies, and flood magnitudes (Wang et al., 2011;Turner et al., 2015). ...
... Zr/Rb has been used as grain-size proxy in marine, lacustrine, and deltaic sediments (Turner et al., 2015), and is often used as a proxy for flood events, because Zr is abundant in coarse sediments (e.g., silt, sand) as a heavy mineral (e.g., zircon), while Rb is abundant in clays (Dypvik and Harris, 2001;Wang et al., 2011;Croudace and Rothwell, 2015). During riverine floods coarser sediments are transported basinwards, so higher values of Zr/Rb can be used for flood frequencies, and flood magnitudes (Wang et al., 2011;Turner et al., 2015). In the Yangtze River Delta plain, China, Wang et al. (2011) were able to reconstruct a 600 year flood record from Zr/Rb, where a high ratio of Zr/Rb was concurrent with flood events. ...
In this thesis, the results of microfossil, biofacies, and geochemical analyses ($\mu$XRF) of the Upper Cretaceous (Turonian) Ferron – Notom Delta, Utah, USA are reported and discussed. The Notom delta is the oldest of three clastic deltas in the Ferron Sandstone Member, Mancos Shale Formation. Foraminifera and testate amoebae were recovered from ninety-eight mudstone samples among five well-exposed outcrops (Caineville North, Steamboat, Blue Hills, Neilson Wash, and Coalmine Wash). Detailed observations showed foraminifera, and testate amoebae tests have undergone post-burial compression (flattening), dissolution, and transport/reworking; therefore, identification of these assemblages to their species level is difficult. The micropaleontological analysis of the Ferron-Notom delta consists of three studies. Morphogroup analysis was applied on foraminifera and testate amoebae, where a relationship between the test morphology and habitat was established. Morphogroup analysis resulted in four main morphogroups and eleven morphotypes and were assigned to life mode, environment, and feeding strategies. Three foraminifera morphogroups and one testate amoebae morphogroup were established indicating a range of environments, from shallow shelf to shallow shelf to lagoon/estuary environments.
Biofacies analysis using the morphotypes was applied on three outcrops (Caineville North, Steamboat, and Blue Hills). We use the morphotypes to define the four main biofacies using cluster analysis, and biodiversity indices. Four biofacies showed marine and fluvial (freshwater) influences. Salinity and OM indices were derived from the relationship of foraminifera morphotypes (BiS, TrS, TS) and testate amoebae morphotypes (Ta-F, Ta-D, Ta-S) that follows lithofacies trends. Because of the under-representation of calcareous foraminifera (due to taphonomic and/or diagenetic factors), the biodiversity indices are treated herein as relative measures. Despite this taphonomic bias, the agglutinated foraminifera and testate amoebae morphogroups show trends with salinity both among the outcrops and stratigraphically within the outcrops. The Blue Hills outcrop represents the most landward and lowest salinity environment (tidally-influenced backwater), Steamboat is more coast proximal with a higher salinity of the delta front and fluvial estuarine environments, and the Caineville North outcrop represents the most coast proximal (fluvial/estuarine to deltaic/prodeltaic) with salinities ranging from low to medium. It appears that the landward transport and coastward of tests was a significant source of taphonomic bias. Nonetheless, the assemblages provide useful depositional information that correlates with previously documented lithofacies data. A salinity index based on a ratio of trochospiral taxa versus testate amoebae was found to provide a useful measure of coastal proximity that matches lithofacies trends.
The μXRF analysis was conducted on twenty-nine mudstone samples from the Caineville North outcrop to examine elemental proxies for paleo-salinity (Sr/Ba), organic matter (K/S), redox (V/Ni), and sediment sources (Zr/Rb, Ti/Fe, Ti/Ca). Twenty-nine surface mudstone samples collected from four lithofacies representing prodelta, delta front, fluvial valley fill and shelf environments. Fourteen elements (Ti, Fe, Ca, Sr, Ba, Ni, Rb, Zr, S, V, Cu, Mn, Si, and K) were used to calculate proxy ratios to detect variations in terrigenous sediments, carbonate production, salinity, grain size, and fluvial inputs in the Caineville North outcrop. Elemental data showed good correspondence between the elemental data and the lithofacies and microfossil indices. Sr/Ba and Ca/Fe showed relationships with carbonate content and proximity to the shoreline. The paleo-salinity proxy (Sr/Ba) did not respond to salinity, but was more responsive to lithological change of carbonate content. The microfossil salinity index seems to be a more accurate paleo-salinity indicator. The proxy for fluvial input of sediment (Zr/Rb and Ti/Fe) agree well with the lithofacies trends, and Zr/Rb and Ti/Fe showed highest values within the fluvial valley fill facies, with higher variability of Ti/Fe compared to the other lithofacies (prodelta, delta front, and shelf), corresponding to response to the proximity of the depositional sites to a fluvial sediment source. The redox proxy V/Ni matched the previously derived microfossil OM index ("bolivind-type" taxa) showing a strong relationship between eutrophication and redox trends. The study aims to establish important baseline geochemical compositions of sediment sources to establish patterns and trends with sediment succession in the deeper basin (offshore; i.e. Mancos Shale). Potentially, these nearshore to fluvial trends will provide important geochemical data to assess changes in paleoclimate, and sea-level in offshore sediment successions.
... Terrigenous sediments were likely derived from streams draining the slopes of the Acrocorinth and local surface runoff from the harbour dredge mounds (Fig. 1) (Morhange et al., 2012;Kolaiti et al., 2017). The element variability could also represent disturbance ('anthroturbation') due to dredging, dumping of spoils, and anchor scour of bottom sediments (Zalasiewicz et al., 2014;Turner et al., 2015). The increase in Pb, terrigenous elements, and abundant pottery refuse within unit 1c may signal the onset of dredging and harbour renovations (ca. ...
Lechaion's inner harbour basin was constructed in the 7th-6th c. BCE and served as Corinth's principal port for over a millennium. The harbour decline and abandonment in the 6th c. CE has been attributed to several causes: natural siltation, co-seismic uplift, coastal subsidence, and damage by tsunami impacts. A multi-proxy palaeoenvironmental study was conducted on seven cores from Lechaion's inner harbour to determine changes in the coastal environments and timing and cause of harbour abandonment. Palaeoenvironments were reconstructed using high-resolution micro-XRF core scanning of sedimentary facies, isotopic (δ¹⁸O, δ¹³C), and micropalaeontological analyses (foraminifera, palynomorphs).
The harbour lithostratigraphy consists of an uppermost (∼1 m) sequence of laminated mud and marl overlying interbedded pebbly sand and mud containing abundant marine microfossils and Roman pottery refuse. A thin (<12 cm) calcrete layer at the base of the marl defines a basin-wide paraconformity, marking a transition from a marine-estuarine harbour basin to a restricted, evaporitic lake. Basin restriction is recorded by a sharp decline in terrigenous elements (Si, Ti, K, Fe), increased Sr, δ¹⁸O, a decline in foraminifera and marine dinoflagellate cysts, and an increase in freshwater algae. The event is constrained by AMS ¹⁴C age modelling to the 6th c. CE and interpreted as rapid, co-seismic uplift of the harbour floor, most likely during destructive earthquakes of 524 and 551/552 CE. These seismic events have been linked to a ∼1.1 m uplift of the nearby Perachora Peninsula and sediment liquefaction structures on-site. No evidence was found for 2nd c. BCE or 6th c. CE tsunami events proposed in previous work. This study represents the most comprehensive geoarchaeological study completed to date in Lechaion's inner harbour and confirms its destruction and abandonment in the 6th c. CE as a result of co-seismic uplift and rapid shoaling of the inner basin.
... Some of the variability within the records can be attributed to grain-size effects: Ti, Zr and Sr appear to be concentrated in the coarser (coarse silt/very fine sand) portions of the sample, while Rb exists at a higher abundance in the finest silt and clay components. These trends are commonly seen in other alluvial sediments of comparable grade (Turner et al., 2015). ...
Elemental XRF analysis carried out on an 8 m long core from the Nile Delta reveals a gradual increase in the Ca/ Ti ratio between 5000 and 4000 cal BP which is linked to the progressive development of hyper-aridity in this region. The increase results from elevated flux of aeolian material entering the Nile river system from calcareous source rock geologies in the dryer Egyptian Sahara. The most major increase in hyper-aridity occurs around 4000 cal BP. Such a perspective suggests a locally abrupt, regionally time-transgressive inception of hyper-aridity in this region at the end of the African Humid Period. After this time, reorganisation of wind circulation meant that less Saharan-derived aeolian material entered the Nile Valley, and the contribution of aeolian material in the Nile's sedimentary signal was also dwarfed by an increase in Blue Nile sedimentary flux. Chronological control is provided by two radiocarbon dates and the top and bottom of a well-constrained pottery horizon that dates from the period of occupation of two nearby archaeological sites: Kom al-Ahmer and Kom Wasit.
... Zr are associated to different grain-size fractions (Turner et al., 2015). In core F-III these layers date between 2.1 and 2.0 ka cal BP. ...
Elba Island was a hotspot of iron mining and smelting in Italy since Etruscan times (6th century BCE). Whereas the environmental burden of modern (base) metal mining in Tuscany is well studied, the impact of both ancient iron mining and smelting on soils in the region is poorly understood. Therefore, we took soil samples from an ancient smelting site and adjacent areas to evaluate the release of trace metal(loid)s from smelting. Additionally, we evaluated ‘metallurgical activity markers’ on the site, i.e. the chemical signature of the production process. The evaluation is based on the soils' element composition, total and pyrogenic carbon contents, pH, and magnetic susceptibility. Statistical analysis include clustering, principal component analysis, and inference tests. Our results indicate that (i) Fe, As, Cu, Ca, total organic, and pyrogenic carbon contents and pH are increased on the smelting site. (ii) This increase corresponds to relatively high contents in these parameters in slag, ore, charcoal, and ash compared to values from background soils. (iii) Metal(loid) contents partly exceed guideline values, but appear negligible compared to (modern) mining – mostly hematite was mined in antiquity, whereas limonite (associated with galena) was only extracted in modern times.
