Multi-proxy Analysis Research Articles

Multi-Proxy analysis in the Gangotri Glacier region, Garhwal Himalaya: Glacial Stratigraphy and the overview of snout retreat, geomorphic evolution, and palaeoclimate signatures

Multi-Proxy analysis in the Gangotri Glacier region, Garhwal Himalaya: Glacial Stratigraphy and the overview of snout retreat, geomorphic evolution, and palaeoclimate signatures

Hydrological disconnection from the Yangtze River triggered rapid environmental degradation in a riverine lake

Interactive River-Flood Ecosystem (RFE) is an important feature characterizing the dynamics of the hydrological connectivity between lake and river worldwide. Any disruption in the RFE can impose significant effects on the functioning of floodplain ecosystems. However, due to the lack of long-term monitoring data, the understanding of the process and mechanism behind limnological responses to the changes in hydrological alterations and nutrient loading in floodplain lakes is restricted. The middle and lower reaches of the Yangtze river floodplain lake system of China is one of the significant food bowls of the nation, and makes important contribution to ecosystem services including drinking water and food to the society for generations. The interactive RFE of the Yangtze floodplain lakes is profoundly disrupted by anthropogenic activities over the recent decades. However, the response of such changes in river-lake connectivity is not comprehensively investigated yet. Here, we studied Cehu Lake in the lower reaches of the Yangtze floodplain system to examine the long-term environmental changes with altered river-lake connectivity and increased nutrient loading using high-resolution paleolimnological multi-proxy analyses including geochemistry, grain size and diatom assemblages of a 210Pb/137Cs dated core. Our results suggest that Cehu Lake have experienced two pronounced shifts: immediately after the damming in Yangtze river (1964) completely ceasing the lake-river connectivity, and in 1994. The disruption in the hydrological connectivity in 1964 led to an abrupt decrease in the abundance of Aulacoseira granulata, and an increase in the organic matter (loss-on-ignition), epiphytic and benthic diatoms, while the disruption in 1994 led to increased total phosphorus (TP), lead (Pb), dry mass accumulation rate, and a decline in Fe/Mn, and consequently enhanced lake eutrophication with emergence of enriched nutrient tolerant diatoms (Cyclotella meneghiniana, Cyclostephanos tholiformis). The redundancy analysis (RDA) showed increased TP loads in lake sediment after damming in the Yangtze river. The condition stimulated macrophyte growth with, but altered diatom flora. Reconnecting Cehu lake with Yangtze river together with reducing nutrient loading to the lake from the incoming river may be an effective management practice to relieve the ecological stress.

A reassessment on the timing and potential drivers of the major seawater 87Sr/86Sr drop in the Ordovician Period: New evidence from conodonts in China

The major drop in marine 87Sr/86Sr records across the Middle-Late Ordovician boundary (Darriwilian-Sandbian) was one of the most dramatic perturbations of the global Sr cycle in Phanerozoic. However, the precise timing of this isotopic event has not been well constrained, partially making it difficult to further clarify the possible drivers of this isotopic event. For this study, we present multi-continental conodont apatite-based Sr-isotope datasets from three well-studied Ordovician carbonate successions in China, i.e., the Huanghuachang section in South China, the Kalpin Shuinichang-Dawangou and the Nanyigou sections in Tarim Basin, northwestern China. Our new 87Sr/86Sr records generally accord with global seawater 87Sr/86Sr secular variation curve and are supposed to be a reflection of coeval primary seawater signatures. Constrained with detailed conodont biostratigraphic and high-resolution δ13C chemostratigraphic framework, the onset of the sharp decline in 87Sr/86Sr ratios was placed within the Histiodella holodentata zone-Eoplacognathus suecicus zone, and approximately synchronous with the initiation of the Middle Darriwilian Carbon Isotope Excursion (MDICE). Numerical modeling reveals that this major 87Sr/86Sr drop could have been generated by a sustainable increase of oceanic hydrothermal (mantle-derived) Sr flux and/or a progressive decrease of continental-derived Sr flux. Multi-proxy analyses further demonstrate that the impact of enhanced oceanic hydrothermal activities accompanying with the accelerating opening of the Rheic and Paleo-Tethys oceans, may have played a central role in driving the major 87Sr/86Sr drop during the Middle-Late Ordovician transition.

Chronological constraints on the late Quaternary Beihai wetland deposits in southwestern China and its depositional history linked to hydroclimate change

As documented in several studies, lake sediments in south-western China are important archives to decipher Indian Summer Monsoon (ISM) variability through reconstructions of precipitation and temperature changes, based on multi-proxy analysis of lake sediments. However, lacustrine records on glacial–interglacial timescales in south-western China remain limited because of a lack of reliable long chronologies. In this paper, we provide a 53 ka chronology for the Beihai wetland (core TCBH14) deposits in combination with luminescence and radiocarbon dating of sediments for the upper 13.4 m of a 36.6 m long drill core. The reliability of our chronological framework was verified within two independent chronology sequences and validated by correlations with regional chronostratigraphy. Results suggest that luminescence dating is a feasible method that can provide reliable age controls for lake sediments in south-western China. The depositional history of the Beihai wetland was characterised by alternating lake and wetland facies. Lakes existed at 52–47 ka, 41–32 ka, 26–19 ka and 11–7 ka, whereas a wetland system prevailed at 47–41 ka, 32–26 ka, 19–11 ka, and after ~7 ka. The patterns and formation periods of alternate lake–wetland successions are consistent with speleothem δ18O and lake δDwax records in South Asia, indicating that the sedimentary evolution of the Beihai wetland and other lake–wetland systems in this region are closely linked to ISM-dominated hydroclimate changes. Correlation of sedimentation rates (SRs) of the studied core (TCBH14) with the cores from 11 additional lakes in south-western China suggest that higher SRs occurred during the periods 47–34 ka, 26–19 ka,15–3 ka, and the early Holocene (11–7 ka). In contrast, lower SRs existed during the periods 50–47 ka, 34–26 ka, the last deglaciation (19–15 ka and 12–11 ka), and the middle Holocene (7–5 ka). Thus, we infer that such quasi-synchronous variations of the SRs from these different lakes in south-western China were strongly controlled by the suborbital- or millennial-scale regional hydroclimate, keeping pace with the Northern Hemisphere insolation-induced ISM variability since the last glaciation.

Multi-proxy approach to identify the origin of high energy coastal deposits from Laem Son National Park, Andaman Sea of Thailand

Understanding the frequency of high energy storm and tsunami events is crucial for apprehending the vulnerability of coastal communities. Identifying and dating sedimentary evidence deposited by such high energy events can assist in the planning and installation of suitable protection measurements. The Andaman Sea coast of Thailand is particularly vulnerable to such events as illustrated by the 2004 Indian Ocean Tsunami. Here, three shore-perpendicular transects and ten sediment cores along a beach ridge in the northern part of Lam Son National Park, Ranong Province, Andaman Sea coast are investigated with respect to high energy deposits. A multi-proxy analysis was conducted including stratigraphical correlations between cores, detailed description of physical characteristics, sedimentary structure, grain size, organic matter and carbonate content as well as identification of the remains of marine organisms. Optically stimulated luminescence (OSL) dating was applied for determining the age of the sediments on this beach ridge plain. The stratigraphy and sediment characteristics, in particular composition, of the sands in the study area clearly allow us to distinguish between high energy deposits and normal beach sediments. Two high energy deposits were identified and attributed to result from the 2004 Indian Ocean Tsunami as well as a past storm, which, based on OSL dating occurred more than 340 ± 20 years ago.

Late Holocene Vegetation and Environmental Changes of Coastal Lowlands in Northern Iran: Possible Role of Climate, Human Impact and Caspian Sea Level Fluctuations

Coastal forests and wetlands play an important role in supporting biodiversity, protecting the hinterlands and shorelines from erosion and also contributing to carbon sequestration and freshwater storage. To reconstruct late Holocene vegetation and environmental dynamics in the coastal lowlands of northern Iran and to detect the possible role of climate, human and Caspian Sea level fluctuation on coastal ecosystems, multi-proxy analysis was applied on the sediment cores from the inland Eynak (EYK) lagoon and near coast Bibi Heybat (BBH) alder swamp. Results shows that in the last 170 years, strong reduction of alder forest occurred around Eynak lagoon, while an expansion occurred in the coastal area in the last 100 years. This indicates that human impact shifted from the near coast to elevated inland, which might be due to the raised water level from the Caspian Sea and the coastal area of BBH region was flooded by brackish water from the Caspian Sea, and was not so suitable for agriculture anymore. This study indicate that alder swamp extent is different between coastal and inland sites, suggesting that further studies of multiple records across the region are needed. Moreover, this study helps to distangle human impacts from wetland processes and thus will be an important contribution to effective climate mitigation and conservation strategies. This multi-proxy study presents important palynological records, which helps to understand past and future impacts of various drivers, such as climate, human impact and sea level changes on wetland ecosystems both regionally and globally.

A multidisciplinary approach to characterise the Early-Middle Holocene palaeoenvironmental evolution of the Sado Valley of Portugal: Implications for late Mesolithic human communities

In this paper we present the results of a multidisciplinary study performed in the Carrasqueira valley, a tributary of the River Sado (SW Portugal), aimed at characterising the Holocene environmental conditions during the late Mesolithic occupation of this valley. Our findings are based on a 13.5 m long sediment core (Arez3) collected on the alluvial plain close to a late Mesolithic shell midden, the Arapouco site. The results of the multiproxy analyses (texture, magnetic susceptibility, organic composition and chemistry, n-alkanes and palynology) point to a greater marine influence between ca. 8850 cal yrs. B.P. (at the core base) and ca. 7450 cal yrs. B.P. (at 750 cm below mean sea level (MSL)) and the existence of an environment similar to the present-day central estuarine basin. At this point in time, sedimentation rates were lower than the rate of sea-level rise, resulting in the formation of a drowned area with intertidal environments developing on the less incised margins. After 7040 cal yrs. B.P. the contribution of organic matter from terrestrial plants and freshwater phytoplankton to the sediment increased, reflecting a change in the sedimentary pattern, with the estuarine environments progressively giving way to freshwater environments. After the Middle Holocene (ca. 6530 cal yrs. B.P.), negative shifts of δ15N to values ~0‰ point to hyper-eutrophication and cyanobacteria bloom episodes under backswamp conditions. According to these results, the estuarine environment prevailed in the area until 7040 cal yrs. B.P. (5090 cal yrs. B.C.; 390 cm below MSL), i.e., during the Mesolithic occupation of the valley, allowing for the occurrence and for the exploitation of marine shellfish and fish by these hunter-gatherer communities at the proximity of the downstream occupation areas.

Strong coupling of the East Asian summer monsoon and hydroclimate footprints during 53–47 ka

A multi-proxy (δ18O, δ13C and trace elements) analysis of an absolutely-dated stalagmite in northern China is conducted to reconstruct the East Asian summer monsoon (EASM) intensity and local hydroclimate conditions during the period of 53.8–47.4 ka (BP, before 1950 CE). Our δ18O and δ13C records, with 24-yr resolution, clearly register the Dansgaard-Oeschger (DO) events 14 and 13. A clear double-peak structure for DO13, as previously detected in the NGRIP ice core, is identified in our δ18O and δ13C records, for the first time. This strong correspondence at the finer time-scale indicates a sensitive and rapid response of the EASM system to the North Atlantic climate changes through air-sea coupling. Our δ18O record shows that the EASM intensity deceased abruptly during latter stage of DO14 (51.1–50.3 ka). This abrupt change is different from other stalagmite δ18O records from central and southern China. On the other hand, both the δ13C and trace element records, representing local hydroclimatic changes, match well with the δ18O record, reflecting an integrated EASM system, on the timescale of the DO cycles. The covariance suggests that the hydrological variation in northern China could be modulated by the movement of the large-scale EASM circulation. Further comparison displays an anti-correlated relationship between the millennial precipitation changes in northern and southeastern China during the period of 51.5–47.4 ka. This anti-correlation is analogous to the “North-South” dipole mode in observed present-day precipitation. Overall, this study advances our understanding of the spatial and temporal evolution of the EASM precipitation on the millennial timescale.

Multi-proxy analysis of a Holocene records from a high-altitude tropical peatland in the Serra do Espinhaço Meridional, Brazil

Peatland ecosystems are valuable archives of paleoenvironmental changes, as they preserve organic and inorganic records that enable the reconstruction of the paleoenvironment. A Holocene record of the Araçuaí River peatland in the Serra do Espinhaço Meridional, in the state of Minas Gerais, Brazil, was studied using isotopic composition, environmental geochemistry, and phytolith analysis. As a result, it was possible to determine and quantify the main constituent elements of the peatland and the chronology of paleoenvironmental changes. Five phases of paleoenvironmental changes were inferred: Phase I – 8.9 to 6.6 cal kyr BP - cold local environment (high phytolith index), which was very wet (higher tree cover density and high occurrence of C3 plants) and with watershed instability (higher incidence of erosion and sedimentation); Phase II – 6.6 to 3.9 kyr - very cold local environment, with reduced moisture in relation to the previous phase (decrease of the temperature and mixture of C3 and C4 plants), and increased stability in the watershed, with episodes of erosion at the end of the phase; Phase III – 3.9 to 2.1 cal kyr BP – warmer, drier local environment in relation to the previous phase (increase in the temperature and decrease of tree cover density) and instability in the watershed, with an episode of temperature decrease and moisture increase (respective increase in the climatic phytolith index and in δ15N) in the middle of the phase; Phase IV – 2.1 to 0.25 kyr - colder climate, increased humidity in the local environment in relation to the previous phase (increase in Ic% and D/P and a decrease in the palm cover density phytolith index), and greater stability in the watershed; Phase V – 0.25 kyr to present - increase in temperature, decrease in humidity (decrease in Ic% and expansion of C4 plants), and increased instability in the watershed, possibly influenced by human activity. The results evidence that the Araçuaí River peatland records demonstrate Holocene climate variations, capable of providing information about the paleoenvironment.

Late Weichselian and Holocene behavior of the Greenland Ice Sheet in the Kejser Franz Josef Fjord system, NE Greenland

To better understand the past retreat patterns and chronologies of major marine-terminating outlet glaciers, the Late Weichselian and Holocene glacial history of a NE Greenland fjord system is reconstructed using new and previously published swath bathymetry and high-resolution seismic data, supplemented with multi-proxy analysis of sediment cores. The investigated area extends more than 190 km, including Fosters Bugt, Kejser Franz Josef Fjord, Nordfjord and Moskusoksefjord, the drainage routes for Waltershausen Gletscher, one of the largest outlet glaciers in the NE sector of the Greenland Ice Sheet. A complex of moraine ridges identified in Fosters Bugt show former stillstand positions during this period, and, alongside radiocarbon ages, supports the theory of a maximum ice front position in the outer coastal areas during the Younger Dryas-Preboreal period. The retreat moraines distributed within the Kejser Franz Josef Fjord system provide evidence of a stepwise retreat during the last deglaciation, whereby rapid retreat was interrupted by episodes of stillstands and/or readvances of the grounding line. The fjord system was mostly deglaciated prior to 7.8 ka cal BP, with an estimated average retreat rate ranging between 33 and 96 m a−1 since the Younger Dryas. Following this, only minor ice advances in the inner fjords have been identified. The sediment supply from Waltershausen Gletscher dominated the Kejser Franz Josef Fjord, Nordfjord and outer Moskusoksefjord throughout the Holocene period, whereas in the middle and inner Moskusoksefjord the sediment deposits reflect a more local catchment area. The estimated average retreat rate is in the same order of magnitude as the rates from fjords of northern Fennoscandia, indicating the same overall control for the deglaciation, ice melting from increased Northern Hemisphere summer insolation that peaked in Early Holocene.

Woodland Management as Major Energy Supply during the Early Industrialization: A Multiproxy Analysis in the Northwest European Lowlands

Wood and charcoal were key sources of energy during early industrialization in Europe (18th century), preceding the large-scale exploitation of fossil coal. Past timber harvesting implied land transformation and woodland resources management. Therefore, relict charcoal kilns and historical documents of forest management are important sources of information about past woodland composition and structure. However, ancient charcoal kilns are poorly documented in temperate woodlands in the lowlands of western Europe, especially combined with historical written sources. In this study, charcoal production was investigated in an area in NE France, by combining charcoal and historical sources analysis, along with innovative dating methodologies. Thus, by using both radiocarbon and optically-stimulated luminescence dating, we showed that the activity lasted until recent times (19th–early 20th centuries) and Carpinus was the dominant taxon in charcoal assemblage. Moreover, kiln attributes seemed to be independent of topographical variables. Woodlands in this area were subject to a coppice-with-standards management, where small diameter wood was preferred to produce charcoal and large diameter stems, mainly Quercus and Fagus, were traded as timber. The dominance of Carpinus is rather uncommon in charcoal studies but supports the importance of Carpinus as fuelwood since the Middle Ages, as confirmed by many written sources.

Linking paleoecology with paleolimnology: evaluating ecological shifts, human impacts and monsoon climate from sediment signals in East Asia

This special issue, entitled “Paleolimnology and Paleoecology in a Rapidly Changing Asia,” was initiated during the third China Workshop on Lake Paleoecology that was held in Kunming, China, in December, 2019. Here, we summarize some of the key findings from the 10 papers that are included in this issue. The papers present sediment surveys of lakes from different parts of East Asia, and studies that spanned a variety of timescales, through multi-proxy analyses of modern samples, short cores and Holocene records. Overall, this special issue provides an up-to-date research snapshot in the fields of paleolimnology and paleoecology from rapidly changing regions of Asia, with a focus on the sediment signals of lake development, ecological shifts and anthropogenic forcing in the context of continuing climatic and societal changes.

Paleotsunami history of Hachinohe, northern Japan: a multiproxy analysis and numerical modeling approach

Paleotsunami studies along the Pacific coast of Tohoku, northern Japan, have been considerably developed recently, particularly after the massive impact of the 2011 Tohoku-oki tsunami. Nevertheless, in the southernmost Shimokita Peninsula, studies pertaining to paleotsunami are underdeveloped, leading to a vague understanding of the tsunamigenic sources northward of the Tohoku region, along with incomplete hazard evaluation. Paleotsunami deposits in Shimokita can be related not only to the Japan Trench along the Sanriku coast but also to the Kuril trench along the Pacific coast of Hokkaido. In this study, we unveiled the paleotsunami history of Hachinohe in northern Tohoku. Using a combination of sedimentological, geochemical, paleontological, and mineralogical proxies, we characterized seven sand layers that dated from ca. 2700 to ca. 5500 yr BP based on radiocarbon (14C) ages as event deposits of marine origin. Sedimentological and paleontological evidence coupled with ground-penetrating radar imagery revealed a marsh environment comprising successive extinct ponds, controlling the depositional environment. Numerical modeling ruled out the possibility of storms as genetic sources, leading to the conclusion that the presence of event deposits with marine sediments in the study area would be associated with tsunami inundation episodes. Based on 14C dating, the mean frequency of recurrence of tsunamis is estimated as 384 years (320–450 yr, 95% confidence interval) and a coefficient of variation of 0.78 (0.68–0.99, 95% confidence interval). The previously recorded limited paleotsunami evidence and absence of an estimated recurrence interval in the Shimokita Peninsula reaffirm the importance of Hachinohe as a tsunami record site for the activity of both trenches.

Late Glacial and Holocene Palaeolake History of the Última Esperanza Region of Southern Patagonia

We undertook multi-proxy analyses on two sediment cores from Lago Pato, a small lake basin at 51°S topographically separated from Lago del Toro in Torres del Paine (TdP), to provide insights into glacier dynamics and lake-level change in the TdP and Última Esperanza region over the last ∼30,000 cal a BP (30 ka). Lago Pato is situated in a region overridden by the Southern Patagonian Ice Field during the Last Glacial and in a transitional climatic zone of Southern Patagonia sensitive to seasonal- to millennial-scale changes in the Southern Hemisphere Westerly Winds (SWW). Results show that a deep ice-dammed and enlarged palaeolake encompassed Lago del Toro and Lago Pato c. 30–20 ka after the ice had retreated from local-Last Glacial Maximum (l-LGM) limits at c. 48–34 ka and during the build-up to the global-Last Glacial Maximum (g-LGM), c. 26–19 ka. Gaps in both sediment records between c. 20–13.4 ka and c. 20–10 ka suggest hiatuses in sediment accumulation during the g-LGM and Antarctic Cold Reversal (ACR) readvances and/or removal by lake lowering or flushing during the Late Glacial–early Holocene. The palaeolake level dropped from >100 m a.s.l. to ∼40–50 m a.s.l. towards the end of the ACR c. 13.4–13.0 ka, creating a shallower glaciolacustrine environment dammed by an ice tongue in the Estancia Puerto Consuelo–Última Esperanza fjord. Further lowering of the enlarged palaeolake level occurred when the ice thinned to <40 m a.s.l., eventually isolating Lago Pato from Lago del Toro and glaciogenic sediment input at c. 11.7 ka. After isolation, the ecology and water levels in Lago Pato became sensitive to regional climate shifts. The shallow, stable, and highly anoxic environment that developed after c. 11.7 ka is associated with weaker (or poleward shifted) SWW at 51°S and was replaced at c. 10 ka by an increasingly productive shallow-littoral lake with a variable lake-level and periodic shifts in anoxic-oxic bottom water conditions and ratios of benthic-planktonic diatoms. A more open Nothofagus forest, established at c. 8.6–7.5 ka, and more arid conditions c. 7.5–5.7 cal ka BP are linked to another phase of weaker (or poleward shifted) SWW at 51°S. More persistently wet conditions from c. 5.7 ka, with extensive closed Nothofagus forests and planktonic diatoms dominant, are associated with stronger (or equatorward shifted) SWW over 51°S. The abrupt return of benthic-to-tychoplanktonic diatoms after c. 3 ka reflects enhanced SWW at 51°S. Increasingly stable lacustrine and littoral wetland conditions established in the last ∼500 years reflect weaker SWW and lasted until recent decades.

Anthropogenic control of coupled changes in organic and inorganic carbon burial in karst landscape: Sediment evidence from two lakes of subtropical China

Hydrological regulation and land uses are known to alter lake organic carbon stock, while inorganic carbon cycling in karst landscapes may as well be shifted due to its rapid kinetic rate. To date, the synchronous pattern in the variations of sediment organic carbon (TOC) and inorganic carbon (TIC) burial in karst lakes largely remains to be quantified along the gradient of catchment development. Two karst lakes with contrasting nutrient level and water depth from Southwest China, both of which were converted to medium-sized reservoirs in ∼1985, were selected for sediment multi-proxy analyses on the temporal and spatial variation of carbon burial in the last ∼80 years. While hydrological fluctuations were well recorded by the sediment variation of particle size, the gradual decrease in median grain size showed a trend of increasing water depth that is consistent with the damming events for both lakes. Meanwhile, the nutrient variables revealed an acceleration of eutrophication since ∼2000 when a rapid expansion of catchment croplands was documented for both lakes. While diatom assemblage showed a significant response to hydro-climatic fluctuation and nutrients at both lakes, algal production (i.e. chlorophyll and cyanobacterial pigments) significantly increased with eutrophication at both lakes. The TIC content in the mesotrophic Taiping Lake and the TOC content in the eutrophic lake of Sanjiaohai both showed a significant increase with agricultural expansion, however, the contents of TOC in Taiping and of TIC in Sanjiaohai remained relatively stable over time. While a significant increase in the sediment flux with decreasing bulk sediment C:N ratios suggests elevated autochthonous input, the temporal change of TIC and TOC flux showed a significant synchrony at both lakes. Meanwhile, the sediment content and flux of TIC is significantly higher than those of TOC in Taiping Lake with a higher rate of carbon turnover, but lower than those of TOC in Sanjiaohai. Thus, the accumulation of TIC was disproportionally promoted in deep lakes while the burial of TOC is more favorable in eutrophic and shallow lakes. Overall, our sediment evidence highlights that agricultural expansion and hydrological regulation could interact in altering the sediment stock of TIC and TOC, and their synchronous variation in Karst landscapes.

Pollen Evidence in Exploring Settlement Dynamics, Land Use, and Subsistence Strategies in the Åland Islands through Multiproxy Analyses from the Lake Dalkarby Träsk Sediment Record

ABSTRACT In this study, which presents pollen, charcoal, and ‘soot’-particle records from a lacustrine sediment core, the development of the cultural landscape around Lake Dalkarby träsk on the Åland Islands in Finland is scrutinised and discussed within a broad temporal setting in order to clarify the long-term interplay between the environment and human activities in this part of the archipelago. Special emphasis is given to the transition period from the Late Iron Age to medieval times due to the dominating humanistic discourse on the settlement dynamics in this region, as in the Åland archipelago in general, arguing for an approximately 150-years-long hiatus in habitation between these two periods, from AD 1050 to 1200. Our results do not support the hiatus theories but show a long and continuous history of the utilisation of land and forest resources starting from prehistoric times. The forests were first cleared with fire for slash-and-burn cultivation. Thereafter, structural diversity in the landscape started to increase. By 1240, the pollen data portrays a picture of a developed agrarian community with a subsistence economy based on arable farming and animal husbandry in which hemp seems to play a substantial part.

Revealing the invisible dead: integrated bio-geoarchaeological profiling exposes human and animal remains in a seemingly ‘empty’ Viking-Age burial

Recent investigations of an apparently ‘empty,’ partly disturbed Viking chamber grave in Denmark (Fregerslev II, dated around the mid-10th century CE) provided an opportunity to develop a novel multi-scale and multi-method analysis of burial and post-burial processes. To overcome the limitations of poor preservation of artefacts and bones, and the lack of a clear macrostratigraphic sequence, we integrated multi-proxy analyses of organic and inorganic materials to study the spatial architecture, burial, and post-depositional processes, including soil chemistry (inductively coupled plasma mass spectrometry - ICPMS, portable X-ray fluorescence spectrometer - pXRF), soil micromorphology, archaeobotany (wood, seeds, fruits, phytoliths), palynology (pollen, non-pollen palynomorphs), and faecal lipid biomarkers. The results enabled the detailed characterisation, spatial analysis, and sequencing of burial deposits, and the identification of post-depositional factors responsible for the poor preservation of the burial. Soil, phytolith and pollen data indicated that the base of the grave was covered with a matting of plant material, and there was no wooden floor. Faecal biomarkers detected substantial amounts of faecal matter, most probably originating from horse faeces, suggesting that a horse died in situ, and trace amounts of pig faeces, which are more likely to have been trampled into the grave. Enriched phosphorus concentrations could be linked to the bodies in the northern and southern sector of the grave. Furthermore, enrichment in lead was found where metal objects were recovered. The findings from Fregerslev II show that integrating high-resolution approaches to the analysis of poorly preserved burial contexts can fundamentally transform archaeological interpretations.

The use of space on two Early Iron Age house sites in South-West Jutland, South Scandinavia: A geoarchaeological multiproxy approach

This paper describes analyses for understanding the general use of space on two Early Iron Age house sites on the site of Sønderris in South-West Jutland (South Scandinavia). The main method consists of the geoarchaeological techniques of soil P analysis by citric acid extraction, low frequency magnetic susceptibility analysis, and measurement of the soils organic content by loss-on-ignition. The results of these analyses are, moreover, interpreted alongside artefact distribution data, data on the dispersal of plant macrofossils, and an evaluation of the architectural details of the sites.At both house sites, the geoarchaeological data shows patterning indicative of human activities. The main achievements are inference of outdoor areas which may have contained pyres or kilns, delineation of yard spaces with refuse deposition, and the characterisation of functional aspects of two small outbuildings. In general, the geoarchaeological results are consistent with the inferences attained from non-geoarchaeological sources. A notable exception is that few clear traces of stalling were identified in the geoarchaeological record, despite the presence of animal booth partition walls indicating the presence of byres in the longhouses. Possible reasons for this are discussed.Overall, this study demonstrates the continued usefulness of long-established geoarchaeological methods for gaining insights about the nature, extent, and orientation of activities on prehistoric house sites. A key take-away from the study is that the potential of any individual method for reading activities (geoarchaeological or otherwise), increases when several techniques with overlapping, but not identical, scope for inferring activities are integrated. The resulting multiproxy analysis is, as a whole, more useful than the sum of its constituent parts.

A drastic change in glacial dynamics at the beginning of the seventeenth century on Novaya Zemlya coincides in time with the strongest volcanic eruption in Peru and the Great Famine in Russia

AbstractIn this study, we reconstructed for the first time the recent 1000-yr-long history of Goluboi tidewater glacier at the eastern side of the Novaya Zemlya, Kara Sea, based on accelerator mass spectrometry 14C dating with higher-resolution age control on the basis of 210Pb and 137Cs radionuclides for the time period after AD 1885, using multiproxy analyses (lithology, mineralogy, and geochemistry) of proximal glaciomarine sediments from the Oga Fjord. Against the background of the active glacial dynamics and the intense meltwater runoff until the end of the sixteenth century, there was a sudden cooling at the beginning of the seventeenth century, which manifested itself in a significant decrease in the sedimentation rates. In time, this event coincides with the strongest volcanic eruption, AD 1600, in South America (in Peru) in the history of human settlement of the continent, which may have plunged the globe into cold climate chaos (Witze, 2008), and caused the Great Famine, AD 1601 to AD 1603, in Russia. The synchronicity of the described events may be an additional fact confirming the global impact of the eruption on the climate of our planet.

First report of diverse vertebrate coprofaunas from the Lower Cretaceous of Tunisia

The Aïn El Guettar Formation in southeastern Tunisia contains one of the most diverse Lower Cretaceous vertebrate assemblages in North Africa. Although the body fossils have been extensively studied over the past years, the associated coprolites are still poorly known. Here new coprolites are comprehensively described from the Chenini and Oum Ed Dhiab members of this formation respectively and ascribed to supposed producers based on a multiproxy analysis. The phosphatic composition, bone inclusions, and internal and external morphologies suggest that these coprolites were produced by a wide range of carnivorous vertebrates. Spiral coprolites from the lower level are mostly amphipolar, suggesting that they were produced by bony fishes, whereas those collected from the upper level are dominated by heteropolar, spirally-coiled coprolites that may have been produced by elasmobranchs. The largest cylindrical coprolites with longitudinal striations, constriction marks, and concentric layers wrapped around a massive core are consistent with those produced by crocodylomorphs. Many specimens from the Chenini Member display different types of desiccation cracks suggesting that the feces were subaerially exposed in a dry environment before burial, however the coprolites from the upper member are devoid of all signs of pre-fossilization abrasion and show smooth surfaces. The highest abundance of coprolites appears to be associated with the lower assemblage, which is congruent with the body fossil record. This study provides tangible evidence about a late Early Cretaceous climatic change in the northern margin of Gondwana and supports previous sedimentology-based assumptions about a dry-to-wet climate transition before the Cenomanian flooding event.