- Email: [email protected]
The environmental transformation from Late Last glacial to Holocene of Otindag sandyland
Abstracts / Quaternary International 279-280 (2012) 462–565
Furthermore, a single 10Be age of 8.90.2 ka from sculpted bedrock situated just inboard of the Marrait moraine is consistent with the bracketing radiocarbon ages. Following deposition of the Marrait moraine, Jakobshavn Isbræ experienced a second advance culminating in deposition of the Tasiussaq moraine. 10Be ages from bedrock immediately inboard of the moraine average 8.00.1 (n¼5) ka, and 10Be ages from boulders on the Tasiussaq moraine average 8.20.1 ka (n¼4). Our chronology suggests that there is a tight link between the deposition of the Fjord Stade moraines and the 9.2 ka and 8.2 ka climate events. THE ORBITAL FORCING OF THE MID-HOLOCENE TRANSITION: A COMPARISON BETWEEN MONSOON RECORDS AND THE RATE OF CHANGES IN THE SOLAR INSOLATION Xuefeng Yu. State Key Laboratory of Loess and Quaternary Geolo, China E-mail address: [email protected]
In this study, the dust flux and the content of trace metallic elements (Ti, Ni, and V) in a peat sequence from the Hongyuan Swamp (32 46.7’N, 102 31.0’E) are used to reconstruct variations in the intensity of the winter monsoon during the Holocene. This record, when compared with the summer monsoon proxy from the same core, can help elucidate the phase relationship between these two systems. The proxy-based reconstructions show different patterns of the winter and summer monsoons before and after 5.5 cal. ka BP. Generally, two monsoons varied reciprocally before 5.5 cal. ka BP; however, after 5.5 cal. ka BP, these two systems exhibit synchronous changes. Moreover, the frequency and amplitude of the variations in these two monsoons are different before and after 5.5 cal. ka BP. The rate of changes in the solar insolation during the Holocene matches well with these monsoon records, implying that the Mid-Holocene transition may have resulted from orbital forcing. HOLOCENE CARBON DYNAMICS OF GLOBAL PEATLANDS: PATTERNS, CONTROLS AND IMPLICATIONS Zicheng Yu. Lehigh University, United States E-mail address: [email protected]
We used the analysis of climate space of modern peatlands, frequency of basal peat ages, and peat C accumulation histories to document and understand the patterns and controls of peatland distribution, initiation and C accumulation of northern, tropical and southern peatlands during the Holocene. Climate envelope analysis defines the “optimum” and “boundaries” of present peatland distribution. Northern peatlands are distributed throughout the climate domain of the boreal forest biome. However, tropical peatlands, especially in Southeast Asia, appear to occur in warm end of climate space, suggesting possible divergent effects of temperature on primary production and decomposition at high temperature. Using basal ages and C accumulation records we estimate that northern peatlands have accumulated 550 GtC. The maximum accumulation occurred in the early Holocene in response to high summer insolation and strong climate seasonality, suggesting the dominant role of temperature-induced productivity over decomposition processes in C accumulation. Tropical peatlands have accumulated 50 GtC, with rapid rates about 8-4 ka affected by a high and more stable sea level, a strong summer monsoon, and before the intensification of El Niño. Southern peatlands, mostly in Patagonia, have accumulated 15 GtC, with rapid accumulation during the Antarctic thermal maximum at 15 ka and during the Holocene thermal maximum at 4-2 ka. The modeled net C balance has a mean value of 42 GtC/kyr for northern peatlands during the Holocene, ranging from 83 GtC/kyr at 9 ka to 22 GtC/ kyr around 2 ka, mostly owing to the delayed effect of long-term decay. Our global peatland synthesis indicates that northern peatlands contributed to the peak in atmospheric CH4 and the decrease in CO2 concentrations in the early Holocene. The large cumulative fluxes and significant variations of global peat C pools throughout the Holocene could explain the CO2 and d 13CO2 patterns as observed from Antarctic ice cores. LACUSTRINE DEEP DRILLING RECORDS OF EAST ASIAN MONSOON CHANGES IN THE PAST 60 KA FROM CLOSED-BASIN LAKES IN CHINA Junqing Yu. Institute of Salt Lake Studies, CAS, China E-mail address: [email protected]
551
Closed-basin lakes are subject to sensitive and large range fluctuations in level in response to climate change. Among which, Lake Nam Co, Lake Qinghai, Lake Daihai and Lake Huangqihai are ideal sites for the study because they lie near the margin of Asian summer monsoon and past changes of monsoon circulation undoubtedly resulted in lake-level fluctuations. Sediment evidence from high-resolution seismic investigation on subbottom sediment structures and from the study of 26-m drill core from Lake Qinghai indicate (1) the paleo-lake size during MIS 3 was much smaller than that of the Holocene and the paleoenvironmental conditions then were neither fully glacial nor fully interglacial, (2) a severely cold and arid climate at LGM brought about near desiccation conditions and the deposition of water-lain loess-like sediments, (3) three abrupt shifts of multiple stratigraphic variables attest to climate instability across the lateglacial/Holocene transition, (4) permanent expansion occurred at the onset of the Holocene, though effective moisture during the early Holocene was lower than the mid and late Holocene, (5) further enhancement of monsoon moisture at the outer margin of the Asian summer monsoon started from w8 ka BP, since then the lake began to expand towards the present-day dimension (27 m deep). The most recent investigation to Lake Nam Co has detected a series of underwater beach remains and folded subbottom sediments in the profundal area of the lake, indicating large range fluctuations in level from possible desiccation during or after the LGM to the water depth of >95 m today (Daut et al., 2010). The reconstructed climate history appears undesignedly to converge with that from Lake Qinghai (Yu and Zhang, 2008), which is consistent as well with the key-site record from South China Sea, the well-studied marginal sea ideal for investigating the Asian monsoon changes (ODP Leg 184 Report, 1999). RS & GIS-BASED SPATIAL ANALYSIS ON ECOLOGICAL CARRYING CAPACITY PATTERN OF NORTHWEST CHINA: DOES SUPPLY MEET DEMAND? Dongxia Yue. Lanzhou Universtiy/MOE Key Laboratory of Western C, China E-mail address: [email protected]
Regional spatial analysis of ecological carrying capacity (abbreviated as ECC hereafter) patterns is an important topic in the field of Ecological Carrying Capacity and sustainable development. To obtain a better understanding on the status of ECC in a given region, it is necessary to evaluate the quantitative ECC gap between demand and supply and analyze its spatial pattern. In this study, northwestern China was chosen as a case study to estimate the difference between ECC demand and ECC supply and analyze the spatial distribution of ECC supply and its related indices at multiple geographic scales on the sub-national region. A modified Ecological Footprint (EF) methodology was employed using high resolution remote sensing data of 2000-year, on the basis of the remote sensing (RS) and geographic information system (GIS) techniques. The results showed that the total ECC supply is 1.44108 gha in Northwestern China in 2000, but the total ECC demand was 1.45108 gha this year. So the total demand is less than the total supply and the total ecological budget was negative, implying that natural capital consumption of human beings had overshot the ECC limitation and Northwestern China was facing with a severe ecological deficit and developmental unsustainability. The crisis degree of ECC demand and supply varied among five provinces and among 358 counties within this region. Furthermore, the spatial distribution of ECC supply was significantly uneven in this region, in which the ECC supply tended to descend from eastern to central part and ascend from central to western part gradually. Further comparison of ECC supply among different landscape types was made. The story of ECC availability was found to be the best in Guanzhong Basin, Yinchuan Basin and some oases in the arid area. As a whole, the difference between ECC demand and supply were in general caused by different geography characteristic, environment condition and land use & land cover in the region. THE ENVIRONMENTAL TRANSFORMATION FROM LATE LAST GLACIAL TO HOLOCENE OF OTINDAG SANDYLAND Leping Yue. Northwest University, China E-mail address: [email protected]
OSL study on sand and fossil soil from Otindag sandy land in eastern China were reported in this paper. Aeolian dune sequences responded to the
552
Abstracts / Quaternary International 279-280 (2012) 462–565
climate change by virtue of alternations of aeolian sand and sandy soil, which corresponded to aridity and humidity conditions, respectively. In this desert, there is a set of contrastive deposits made up of loose sand and overlying dark sandy soil just below land surface. Optical dating using SAR technique with quartz was applied to the deposits. The results indicate that the developed soil and underlying deep aeolian sand are responses to the Holocene optimum (H.O.) and the last late glacial, respectively. The rough extension of last late glacial sand was revealed by studying about 26 profiles. Combined with studies of grain-size, magnetic susceptibility and sediment color, the environment of the desert is reconstructed. The results suggest that the mobile sand was stabilized and contracted gradually when approaching Holocene. It was completely covered by vegetation in H.O. With rivers and lakes inside Otindag Desert developed the water level of them has lowered in the dry and cold environment of the glacial stage and the rivers and lakes subjected to wind erosion and reform has provided the enlargement of drift sand with material resources. ENIGMA OF THE MIDDLE VALDAYN Lavrushin Yuri. Moscow, Russian Federation E-mail address: [email protected]
The Middle Valdayn (Middle Würm) is a non-glacial interval of the Late Pleistocene. A paleoclimatic situation of the Russian Plain was characterized by instable climatic conditions, alternation of thermochrons and cryochrons, and absence of zonal vegetation type even in the warmest time intervals. Trends of environmental changes in the Russian Plain were formed under a great influence of the Atlantic-Arctic oceanic climatic “machine”. The important components of the “machine” were advections of the Atlantic waters (AAW) into the Arctic Ocean and those of the polar waters (APW) into the Atlantic Ocean. The AAW promoted destruction of the ice cover in the ocean and the warming in the land. The APW brought into the Atlantic not only the polar waters but large masses of sea ice. This changed the water structure, diminished an influence of the warm Gulf Stream, and caused great changes in tachyhalyne circulation in the Atlantic Ocean. In addition, the western transportation of air masses appeared to be significantly different from that of interglacials. Palynological data show that the Russian Plain environments were affected by the air masses from Siberia (during thermochrons), Middle Asia and the Arctic (during cryochrons). The appearance of “ice glaciation” in the Atlantic Ocean provided specific non-glacial climatic conditions both in the Russian Plain and Europe. At present welldefined correlations between different advections and environmental changes in the Russian Plain are geochronologically controlled. TERMINAL PALEOLITH ENVIRONMENTAL EVENTS IN THE DIVNOGOR'E REGION (MIDDLE DON RIVER) Lavrushin Yuri. Moscow, Russian Federation E-mail address: [email protected]
Studies of the archaeological object Divnogor'e-9 revealed a succession of environmental events of the terminal Late Pleistocene. The object is located at the mouth of ravine which cut the Central Russian Upland margin formed by chalk. Deposits of the ravine widening compose three units. The lower unit is represented by alternating sediments of mud flows and basins. At the sediment contacts there are rich accumulations of bones and skeletons of Equus cabbalus. The unit includes five levels of bone accumulations; level 5 is dated at about 14 ka, ages of the other levels are estimated from 13,5 to 13,0 ka. Level 3 contains a working landing with numerous siliceous artefacts. Many horses came to the ravine because the basins contained a lot of dissolved chalk which was dainties for them. Mud flows from heavy rains caused death of horses. The middle unit of landfall and detrital deposits was most likely formed due to seismic processes. The upper unit of slope diluvium contains two buried soils. A top of the lower soils is represented by wood coal. This may evidence for a local fire caused by an activity of an ancient man. The upper soil contains wood pollen. The most favorable conditions for diluvium formation are provided by light rains, which wash out the deposits. The buried soils reflect breaks of the process. During the formation of diluvium and mudflows herbal vegetation dominated.
A model of deposition of the lower unit was prepared and a specific technique of hunting of ancient man was reconstructed. ANALYSIS OF VEGETATION AND ENVIRONMENTAL CHANGES SINCE 11.5 KY BP FROM EXTINCT OXBOW LAKE, FLOOD PLAIN OF THE ELBE RIVER, CZECH REPUBLIC Pavla Zácková. Charles University in Prague, Faculty of Nature Sc, Czech Republic E-mail address: [email protected]
The Late Glacial palaeomeander Chrast is situated in the area of the middle Elbe river floodplain, where a huge number of paleomeanders of the Holocene age are preserved. This area is typical for a presence of the unique complex of the relict wetlands and fen meadows, which used to be widely spread in the Holocene. Presented research is a part of large multi-proxy project dealing on coevolution of human impact and natural processes of the landscape in this region during the Late Quaternary. Investigated profile (total depth 285 cm) was obtained from an oxbow lake. Plant macro and micro-fossils were studied with supportive evidences from geochemical and sedimentological data. Based on the results profile was divided into 5 zones (A1-A5). Last 110 cm (A1-A3) contains the unique record of Allerød vegetation. Sediment of the base of the palaeomeander (11 450 60 BP) contain record of macrophyte vegetation (Nuphar lutea, Batrachium, Potamogeton ssp). The local pollen spectra give an evidence of occurrence of aquatic species (Myriophyllum spicatum - type, Pediastrum, Sparganium/Typha angustifolia). Subsequently organic production increased rapidly during 11 523 120 BP (A2) and shallow lake was filled in. This is supported by presence of macroremains of Carex vesiraria/rostrata, C. riparia, Menyanthes trifoliata. Salix, Betula and Pinus wood fragments were also recorded indicating presence of birch-pine forest with intermingle of a spruce. Fires, which were frequent during the end of the Last Glacial, are documented by the record of a large number of burned seeds and charcoal. Calcium carbonate accumulations of the lake marl originated at the beginning of the Younger Dryas (11 010 60 BP). Increased sand deposits (A4) indicate a change from meandering type of the river to the braided one. The end of the sand deposition might be linked with the Glacial/ Holocene transition phase. Local human impact (A5) is documented in the middle of the Holocene (6510 40 BP). HIGH-RESOLUTION RECONSTRUCTION OF CLIMATE AND ENVIRONMENTAL HISTORY DURING FUNNEL-BEAKER CULTURE TIME BASED ON ANNUALLY LAMINATED LAKE SEDIMENTS OF LAKE BELAU AND LAKE POGGENSEE (NORTHERN GERMANY) Jürgen Zahrer. University Kiel, Institute for Ecosystem Research, Germany E-mail address: [email protected]
Synchronous deposition patterns of varves of two lakes in northern Germany were used to reconstruct climate history during the Funnelbeaker culture in north central Europe (5200-6900 cal BP) based on microfacies analysis. The onset of agricultural land use in the catchment areas of these lakes has been detected, too. The dating and synchronisation of the sequences are carried out by radiocarbon dating, tephrochronology and the varve chronology. For climate reconstruction a group of comparative indicators was applied: 1.) thickness of annual layers and the seasonal sub-laminae. 2.) palaeolimnologic-paleoclimatic indicators: Diatoms (genera), Phacotus spec., Crysophytes, autochthonous carbonate precipitation, detrital reworked carbonates, organic and minerogenic input.
A phase of cooler climatic conditions from 6050-5850 cal BP was detected and might reflect the known climatic event of the northern hemisphere (Bond event 4). The high temporal resolution enabled a further zoning: Besides four phases characterised by cold conditions a short, warm and dry phase was detected. Simultaneously, enrichment in minerogenic components and charcoal, preceding the onset of distinct settlement indicators for centuries, might suggest slope instability caused by natural forest fires. The following millenium showed indication for warmer climatic
Furthermore, a single 10Be age of 8.90.2 ka from sculpted bedrock situated just inboard of the Marrait moraine is consistent with the bracketing radiocarbon ages. Following deposition of the Marrait moraine, Jakobshavn Isbræ experienced a second advance culminating in deposition of the Tasiussaq moraine. 10Be ages from bedrock immediately inboard of the moraine average 8.00.1 (n¼5) ka, and 10Be ages from boulders on the Tasiussaq moraine average 8.20.1 ka (n¼4). Our chronology suggests that there is a tight link between the deposition of the Fjord Stade moraines and the 9.2 ka and 8.2 ka climate events. THE ORBITAL FORCING OF THE MID-HOLOCENE TRANSITION: A COMPARISON BETWEEN MONSOON RECORDS AND THE RATE OF CHANGES IN THE SOLAR INSOLATION Xuefeng Yu. State Key Laboratory of Loess and Quaternary Geolo, China E-mail address: [email protected]
In this study, the dust flux and the content of trace metallic elements (Ti, Ni, and V) in a peat sequence from the Hongyuan Swamp (32 46.7’N, 102 31.0’E) are used to reconstruct variations in the intensity of the winter monsoon during the Holocene. This record, when compared with the summer monsoon proxy from the same core, can help elucidate the phase relationship between these two systems. The proxy-based reconstructions show different patterns of the winter and summer monsoons before and after 5.5 cal. ka BP. Generally, two monsoons varied reciprocally before 5.5 cal. ka BP; however, after 5.5 cal. ka BP, these two systems exhibit synchronous changes. Moreover, the frequency and amplitude of the variations in these two monsoons are different before and after 5.5 cal. ka BP. The rate of changes in the solar insolation during the Holocene matches well with these monsoon records, implying that the Mid-Holocene transition may have resulted from orbital forcing. HOLOCENE CARBON DYNAMICS OF GLOBAL PEATLANDS: PATTERNS, CONTROLS AND IMPLICATIONS Zicheng Yu. Lehigh University, United States E-mail address: [email protected]
We used the analysis of climate space of modern peatlands, frequency of basal peat ages, and peat C accumulation histories to document and understand the patterns and controls of peatland distribution, initiation and C accumulation of northern, tropical and southern peatlands during the Holocene. Climate envelope analysis defines the “optimum” and “boundaries” of present peatland distribution. Northern peatlands are distributed throughout the climate domain of the boreal forest biome. However, tropical peatlands, especially in Southeast Asia, appear to occur in warm end of climate space, suggesting possible divergent effects of temperature on primary production and decomposition at high temperature. Using basal ages and C accumulation records we estimate that northern peatlands have accumulated 550 GtC. The maximum accumulation occurred in the early Holocene in response to high summer insolation and strong climate seasonality, suggesting the dominant role of temperature-induced productivity over decomposition processes in C accumulation. Tropical peatlands have accumulated 50 GtC, with rapid rates about 8-4 ka affected by a high and more stable sea level, a strong summer monsoon, and before the intensification of El Niño. Southern peatlands, mostly in Patagonia, have accumulated 15 GtC, with rapid accumulation during the Antarctic thermal maximum at 15 ka and during the Holocene thermal maximum at 4-2 ka. The modeled net C balance has a mean value of 42 GtC/kyr for northern peatlands during the Holocene, ranging from 83 GtC/kyr at 9 ka to 22 GtC/ kyr around 2 ka, mostly owing to the delayed effect of long-term decay. Our global peatland synthesis indicates that northern peatlands contributed to the peak in atmospheric CH4 and the decrease in CO2 concentrations in the early Holocene. The large cumulative fluxes and significant variations of global peat C pools throughout the Holocene could explain the CO2 and d 13CO2 patterns as observed from Antarctic ice cores. LACUSTRINE DEEP DRILLING RECORDS OF EAST ASIAN MONSOON CHANGES IN THE PAST 60 KA FROM CLOSED-BASIN LAKES IN CHINA Junqing Yu. Institute of Salt Lake Studies, CAS, China E-mail address: [email protected]
551
Closed-basin lakes are subject to sensitive and large range fluctuations in level in response to climate change. Among which, Lake Nam Co, Lake Qinghai, Lake Daihai and Lake Huangqihai are ideal sites for the study because they lie near the margin of Asian summer monsoon and past changes of monsoon circulation undoubtedly resulted in lake-level fluctuations. Sediment evidence from high-resolution seismic investigation on subbottom sediment structures and from the study of 26-m drill core from Lake Qinghai indicate (1) the paleo-lake size during MIS 3 was much smaller than that of the Holocene and the paleoenvironmental conditions then were neither fully glacial nor fully interglacial, (2) a severely cold and arid climate at LGM brought about near desiccation conditions and the deposition of water-lain loess-like sediments, (3) three abrupt shifts of multiple stratigraphic variables attest to climate instability across the lateglacial/Holocene transition, (4) permanent expansion occurred at the onset of the Holocene, though effective moisture during the early Holocene was lower than the mid and late Holocene, (5) further enhancement of monsoon moisture at the outer margin of the Asian summer monsoon started from w8 ka BP, since then the lake began to expand towards the present-day dimension (27 m deep). The most recent investigation to Lake Nam Co has detected a series of underwater beach remains and folded subbottom sediments in the profundal area of the lake, indicating large range fluctuations in level from possible desiccation during or after the LGM to the water depth of >95 m today (Daut et al., 2010). The reconstructed climate history appears undesignedly to converge with that from Lake Qinghai (Yu and Zhang, 2008), which is consistent as well with the key-site record from South China Sea, the well-studied marginal sea ideal for investigating the Asian monsoon changes (ODP Leg 184 Report, 1999). RS & GIS-BASED SPATIAL ANALYSIS ON ECOLOGICAL CARRYING CAPACITY PATTERN OF NORTHWEST CHINA: DOES SUPPLY MEET DEMAND? Dongxia Yue. Lanzhou Universtiy/MOE Key Laboratory of Western C, China E-mail address: [email protected]
Regional spatial analysis of ecological carrying capacity (abbreviated as ECC hereafter) patterns is an important topic in the field of Ecological Carrying Capacity and sustainable development. To obtain a better understanding on the status of ECC in a given region, it is necessary to evaluate the quantitative ECC gap between demand and supply and analyze its spatial pattern. In this study, northwestern China was chosen as a case study to estimate the difference between ECC demand and ECC supply and analyze the spatial distribution of ECC supply and its related indices at multiple geographic scales on the sub-national region. A modified Ecological Footprint (EF) methodology was employed using high resolution remote sensing data of 2000-year, on the basis of the remote sensing (RS) and geographic information system (GIS) techniques. The results showed that the total ECC supply is 1.44108 gha in Northwestern China in 2000, but the total ECC demand was 1.45108 gha this year. So the total demand is less than the total supply and the total ecological budget was negative, implying that natural capital consumption of human beings had overshot the ECC limitation and Northwestern China was facing with a severe ecological deficit and developmental unsustainability. The crisis degree of ECC demand and supply varied among five provinces and among 358 counties within this region. Furthermore, the spatial distribution of ECC supply was significantly uneven in this region, in which the ECC supply tended to descend from eastern to central part and ascend from central to western part gradually. Further comparison of ECC supply among different landscape types was made. The story of ECC availability was found to be the best in Guanzhong Basin, Yinchuan Basin and some oases in the arid area. As a whole, the difference between ECC demand and supply were in general caused by different geography characteristic, environment condition and land use & land cover in the region. THE ENVIRONMENTAL TRANSFORMATION FROM LATE LAST GLACIAL TO HOLOCENE OF OTINDAG SANDYLAND Leping Yue. Northwest University, China E-mail address: [email protected]
OSL study on sand and fossil soil from Otindag sandy land in eastern China were reported in this paper. Aeolian dune sequences responded to the
552
Abstracts / Quaternary International 279-280 (2012) 462–565
climate change by virtue of alternations of aeolian sand and sandy soil, which corresponded to aridity and humidity conditions, respectively. In this desert, there is a set of contrastive deposits made up of loose sand and overlying dark sandy soil just below land surface. Optical dating using SAR technique with quartz was applied to the deposits. The results indicate that the developed soil and underlying deep aeolian sand are responses to the Holocene optimum (H.O.) and the last late glacial, respectively. The rough extension of last late glacial sand was revealed by studying about 26 profiles. Combined with studies of grain-size, magnetic susceptibility and sediment color, the environment of the desert is reconstructed. The results suggest that the mobile sand was stabilized and contracted gradually when approaching Holocene. It was completely covered by vegetation in H.O. With rivers and lakes inside Otindag Desert developed the water level of them has lowered in the dry and cold environment of the glacial stage and the rivers and lakes subjected to wind erosion and reform has provided the enlargement of drift sand with material resources. ENIGMA OF THE MIDDLE VALDAYN Lavrushin Yuri. Moscow, Russian Federation E-mail address: [email protected]
The Middle Valdayn (Middle Würm) is a non-glacial interval of the Late Pleistocene. A paleoclimatic situation of the Russian Plain was characterized by instable climatic conditions, alternation of thermochrons and cryochrons, and absence of zonal vegetation type even in the warmest time intervals. Trends of environmental changes in the Russian Plain were formed under a great influence of the Atlantic-Arctic oceanic climatic “machine”. The important components of the “machine” were advections of the Atlantic waters (AAW) into the Arctic Ocean and those of the polar waters (APW) into the Atlantic Ocean. The AAW promoted destruction of the ice cover in the ocean and the warming in the land. The APW brought into the Atlantic not only the polar waters but large masses of sea ice. This changed the water structure, diminished an influence of the warm Gulf Stream, and caused great changes in tachyhalyne circulation in the Atlantic Ocean. In addition, the western transportation of air masses appeared to be significantly different from that of interglacials. Palynological data show that the Russian Plain environments were affected by the air masses from Siberia (during thermochrons), Middle Asia and the Arctic (during cryochrons). The appearance of “ice glaciation” in the Atlantic Ocean provided specific non-glacial climatic conditions both in the Russian Plain and Europe. At present welldefined correlations between different advections and environmental changes in the Russian Plain are geochronologically controlled. TERMINAL PALEOLITH ENVIRONMENTAL EVENTS IN THE DIVNOGOR'E REGION (MIDDLE DON RIVER) Lavrushin Yuri. Moscow, Russian Federation E-mail address: [email protected]
Studies of the archaeological object Divnogor'e-9 revealed a succession of environmental events of the terminal Late Pleistocene. The object is located at the mouth of ravine which cut the Central Russian Upland margin formed by chalk. Deposits of the ravine widening compose three units. The lower unit is represented by alternating sediments of mud flows and basins. At the sediment contacts there are rich accumulations of bones and skeletons of Equus cabbalus. The unit includes five levels of bone accumulations; level 5 is dated at about 14 ka, ages of the other levels are estimated from 13,5 to 13,0 ka. Level 3 contains a working landing with numerous siliceous artefacts. Many horses came to the ravine because the basins contained a lot of dissolved chalk which was dainties for them. Mud flows from heavy rains caused death of horses. The middle unit of landfall and detrital deposits was most likely formed due to seismic processes. The upper unit of slope diluvium contains two buried soils. A top of the lower soils is represented by wood coal. This may evidence for a local fire caused by an activity of an ancient man. The upper soil contains wood pollen. The most favorable conditions for diluvium formation are provided by light rains, which wash out the deposits. The buried soils reflect breaks of the process. During the formation of diluvium and mudflows herbal vegetation dominated.
A model of deposition of the lower unit was prepared and a specific technique of hunting of ancient man was reconstructed. ANALYSIS OF VEGETATION AND ENVIRONMENTAL CHANGES SINCE 11.5 KY BP FROM EXTINCT OXBOW LAKE, FLOOD PLAIN OF THE ELBE RIVER, CZECH REPUBLIC Pavla Zácková. Charles University in Prague, Faculty of Nature Sc, Czech Republic E-mail address: [email protected]
The Late Glacial palaeomeander Chrast is situated in the area of the middle Elbe river floodplain, where a huge number of paleomeanders of the Holocene age are preserved. This area is typical for a presence of the unique complex of the relict wetlands and fen meadows, which used to be widely spread in the Holocene. Presented research is a part of large multi-proxy project dealing on coevolution of human impact and natural processes of the landscape in this region during the Late Quaternary. Investigated profile (total depth 285 cm) was obtained from an oxbow lake. Plant macro and micro-fossils were studied with supportive evidences from geochemical and sedimentological data. Based on the results profile was divided into 5 zones (A1-A5). Last 110 cm (A1-A3) contains the unique record of Allerød vegetation. Sediment of the base of the palaeomeander (11 450 60 BP) contain record of macrophyte vegetation (Nuphar lutea, Batrachium, Potamogeton ssp). The local pollen spectra give an evidence of occurrence of aquatic species (Myriophyllum spicatum - type, Pediastrum, Sparganium/Typha angustifolia). Subsequently organic production increased rapidly during 11 523 120 BP (A2) and shallow lake was filled in. This is supported by presence of macroremains of Carex vesiraria/rostrata, C. riparia, Menyanthes trifoliata. Salix, Betula and Pinus wood fragments were also recorded indicating presence of birch-pine forest with intermingle of a spruce. Fires, which were frequent during the end of the Last Glacial, are documented by the record of a large number of burned seeds and charcoal. Calcium carbonate accumulations of the lake marl originated at the beginning of the Younger Dryas (11 010 60 BP). Increased sand deposits (A4) indicate a change from meandering type of the river to the braided one. The end of the sand deposition might be linked with the Glacial/ Holocene transition phase. Local human impact (A5) is documented in the middle of the Holocene (6510 40 BP). HIGH-RESOLUTION RECONSTRUCTION OF CLIMATE AND ENVIRONMENTAL HISTORY DURING FUNNEL-BEAKER CULTURE TIME BASED ON ANNUALLY LAMINATED LAKE SEDIMENTS OF LAKE BELAU AND LAKE POGGENSEE (NORTHERN GERMANY) Jürgen Zahrer. University Kiel, Institute for Ecosystem Research, Germany E-mail address: [email protected]
Synchronous deposition patterns of varves of two lakes in northern Germany were used to reconstruct climate history during the Funnelbeaker culture in north central Europe (5200-6900 cal BP) based on microfacies analysis. The onset of agricultural land use in the catchment areas of these lakes has been detected, too. The dating and synchronisation of the sequences are carried out by radiocarbon dating, tephrochronology and the varve chronology. For climate reconstruction a group of comparative indicators was applied: 1.) thickness of annual layers and the seasonal sub-laminae. 2.) palaeolimnologic-paleoclimatic indicators: Diatoms (genera), Phacotus spec., Crysophytes, autochthonous carbonate precipitation, detrital reworked carbonates, organic and minerogenic input.
A phase of cooler climatic conditions from 6050-5850 cal BP was detected and might reflect the known climatic event of the northern hemisphere (Bond event 4). The high temporal resolution enabled a further zoning: Besides four phases characterised by cold conditions a short, warm and dry phase was detected. Simultaneously, enrichment in minerogenic components and charcoal, preceding the onset of distinct settlement indicators for centuries, might suggest slope instability caused by natural forest fires. The following millenium showed indication for warmer climatic