- Email: [email protected]
Pollen-based reconstruction of vegetation and enviro-nments in the Verkhoyansk Mountains region (Siberia, Russia) during the past 50 ka
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Abstracts / Quaternary International 279-280 (2012) 233–345
base of the Kalkkop core, but an infinite date was obtained near the top of the core, the chronology is therefore questionable. Ancient lakes provide rare long and high resolution records of fluctuating palaeo-environments and used as a tool to investigate the link between terrestrial/atmospheric palaeodata and marine record to supplement, refine regional and broader models of palaeoclimate and ecosystem evolution. Therefore the aims of the study is to extract palaeodata, with emphasis on critical time intervals, like past warm periods as an analogue for present and future regional/ global climate change to inform policy-making in terms of adaptation and developing the site to enhance its value in terms of ecotourism and education. These will be done by geological mapping of the area, combined with sedimentological, palaeontological, biogeochemical and stable isotope studies of existing drilled bore holes. CLIMATE EFFECT OF DUST AEROSOL IN SOUTHERN CHINESE LOESS PLATEAU SINCE THE LAST GLACIAL PERIOD Yan Mu. Institute of Geology and Geophysics,Chinese Academ, China E-mail address: [email protected]
Dust aerosol is one of natural aerosols and plays an important role in the climate system. In recent years, more and more investigators began to pay attention to the climate impact of dust aerosol. However, most studies were mainly focused on modern dust aerosol. Research on the climate effect of dust aerosols in Quaternary was few. In the study, the climate effect of dust aerosol in the south of Chinese Loess Plateau over the past 60 kaB.P was studied by using the grain-size distribution and the settlement velocity of loess deposition. The radiative effect of dust aerosols was usually to result in an increasing albedo of the earth-atmosphere system that therefore leaded climate cooling. The climate effect of dust aerosols was a negative feedback. The albedo of the earth-atmospheric system increased during the warm Holocene Optimal but decreased during the last glacial period. During Heinrich cooling events, the cooling effect of dust aerosols was lower and did not reduce the air temperature of the earth system. It is possible to estimate the climate effect of dust aerosol in past by using the grain size distribution and the settlement velocity of loess-paleosol formations. CLIMATE CHANGE IN THE BLACK SEA CORRIDOR DURING THE UPPER PALEOLITHIC TRANSITION, LATE GLACIAL MAXIMUM AND OSCILLATING WARM-COLD PRE-BOREAL EVENTS
during warmer Allerod-Bölling events, providing further evidence for forest refugia in the western Pontic mountains. POLLEN-BASED RECONSTRUCTION OF VEGETATION AND ENVIRONMENTS IN THE VERKHOYANSK MOUNTAINS REGION (SIBERIA, RUSSIA) DURING THE PAST 50 KA Stefanie Müller. Freie Universität Berlin, Institute of Geological , Germany E-mail address: [email protected]
We present a detailed radiocarbon-dated 936 cm long pollen record from Lake Billyakh (6517’N, 126 47’E; 340 m a.s.l.) situated in the western part of the Verkhoyansk Mountains. A set of 53 surface pollen samples representing tundra, cold-deciduous forest and taiga communities was collected in Yakutia to verify the accuracy of the quantitative biome reconstruction method and to obtain a more precise attribution of the identified pollen taxa to the main regional biomes. The adjusted method is applied to the pollen record from Lake Billyakh to gain an objective reconstruction of vegetation and environments since about 50.7 ka BP. The results of both approaches suggest that herbaceous tundra and steppe communities dominated the area from 50.7 to 13.5 ka BP. A relative high content of taxa representing shrub tundra communities and the presence of larch pollen recorded prior to 31 ka and after 13.5 ka BP likely indicate interstadial climate amelioration associated with the middle and latest parts of the last glacial. Increasing pollen percentages of herbaceous taxa around 12 ka BP suggests broader distribution of drier communities in response to the colder and drier than present climate of the Younger Dryas. The onset of the Holocene is marked by the highest values of shrub taxa. Pollen percentages of arboreal taxa increase gradually and reach maximum values after 7 ka BP mainly reflecting the spread of Pinus sylvestris in central Yakutia as a response to the mid-Holocene climatic optimum. The most striking feature of the pollen record is the quasicontinuous presence of larch, shrubby birch and alder pollen throughout the whole record suggesting that larch possibly survived in locally favorable environments in the study region during the last 50 ka BP. Noticeable variations in larch pollen percentages point to multiple short-term warming episodes, which might be synchronous with the North Atlantic Dansgaard-Oeschger events. HIGH-RESOLUTION DIRECT CHEMICAL ANALYSIS OF DUST IN FROZEN ICE CORES BY CRYO-CELL LASER-ABLATION ICPMS
Peta Mudie. Memorial University Newfoundland, Canada
Wolfgang Muller. Royal Holloway University of London, United Kingdom
E-mail address: [email protected]
E-mail address: [email protected]
The history of climate and sea level change in the Black Sea region and its impact on the evolution of modern human populations over the past ca. 50,000 cal ybp is of salient importance to archaeologists and paleoclimatologists. A major question asks why and how early modern humans could displace Neanderthals who successfully occupied periglacial environments from 400 – 40 kaBP, but disappeared following a major volcanigenic interval in the eastern Mediterranean around 40 kaBP. Palynological studies of AMS shell-dated sediment cores from the western Black Sea (MAR 98-04) and eastern Marmara Sea (MAR 98-07, 98-012, MAR 94-05 and MAR2-89) provide a semi-continuous centennial-scale record of the vegetation, paleoclimate and paleohydrology for the time interval from around 45,000 to 11,703 cal ybp. Despite uncertainty about the exact age of the oldest mollusk shell dates, pollen records support interpretations that the a major climatic deterioration (“volcanic winter”) followed the volcanic event at the beginning of HS-4, followed by an amelioration and return of mesic forest by 34,963 cal ybp until shortly after D-O 3 at 27,931 cal bp. During this “volcanic winter”, the Black and Marmara seas supported different brackish-fresh water floras. New studies are focusing on palynological records of climate variability in the Marmara Sea region during the Paleolithic – Mesolithic late glacial and pre-Boreal interval from 30,490 -11,702 cal ybp, including the intervals correlative with HS 3 – 1 and GIS 5 – 1. Initial results show the interval from ca. 22,865 – 15,600 ca ybp was a largely cold, dry steppe/macchi landscape, but forest vegetation with deciduous oaks (Quercus) and chestnut (Castanea) trees rapidly appeared
High-latitude ice cores have become the master records of Pleistocene climate variability. Especially the high-resolution data from Greenland reveal a remarkably change:able glacial climate, and these rapid climate oscillations have recently been shown to take place within a few years only. The relative sequence of proxy records of dust, temperature or greenhouse gases allows identification of potential cause-effect relationships. For this to be successful, palaeoclimate information must be extracted at the highest possible, i.e. sub-annual, resolution. We present a new technique for controlled in-situ chemical analysis of ice cores at w0.1 mm resolution, which focuses on seasalt and dust tracers. It utilizes a custom-built, peltier-cooled cryo-sample holder fully compatible with a two-volume Laurin LA-cell, in turn coupled to a Resonetics M-50 excimer LA system and an Agilent 7500cs ICPMS. Using 3 x 5 cm strips of ice cores per sample holder, this setup allows elemental concentrations to be acquired using both depth-profiling along chains of spots and/or as continuous lateral profiles. Seasalt or dust tracers such as Mg, Ca, Al and Fe have limits of detection in the low(est) ppb-range, facilitated for Ca and Fe by using H2 as collision-cell gas in ICPMS. This facilitates 1) subseasonal and/or longer-term element concentration variations to be detected and 2) location of chemical impurities in recrystallizing ice to be identified. As such, Dansgaard-Oeschger (DO) events can be analyzed at unprecedented resolution. Initial data for last glacial maximum NGRIP ice overall show annual variability in Mg, Al, Fe, Ca compatible with annual cyclicity, but also remarkable small scale variability, which will be presented.
Abstracts / Quaternary International 279-280 (2012) 233–345
base of the Kalkkop core, but an infinite date was obtained near the top of the core, the chronology is therefore questionable. Ancient lakes provide rare long and high resolution records of fluctuating palaeo-environments and used as a tool to investigate the link between terrestrial/atmospheric palaeodata and marine record to supplement, refine regional and broader models of palaeoclimate and ecosystem evolution. Therefore the aims of the study is to extract palaeodata, with emphasis on critical time intervals, like past warm periods as an analogue for present and future regional/ global climate change to inform policy-making in terms of adaptation and developing the site to enhance its value in terms of ecotourism and education. These will be done by geological mapping of the area, combined with sedimentological, palaeontological, biogeochemical and stable isotope studies of existing drilled bore holes. CLIMATE EFFECT OF DUST AEROSOL IN SOUTHERN CHINESE LOESS PLATEAU SINCE THE LAST GLACIAL PERIOD Yan Mu. Institute of Geology and Geophysics,Chinese Academ, China E-mail address: [email protected]
Dust aerosol is one of natural aerosols and plays an important role in the climate system. In recent years, more and more investigators began to pay attention to the climate impact of dust aerosol. However, most studies were mainly focused on modern dust aerosol. Research on the climate effect of dust aerosols in Quaternary was few. In the study, the climate effect of dust aerosol in the south of Chinese Loess Plateau over the past 60 kaB.P was studied by using the grain-size distribution and the settlement velocity of loess deposition. The radiative effect of dust aerosols was usually to result in an increasing albedo of the earth-atmosphere system that therefore leaded climate cooling. The climate effect of dust aerosols was a negative feedback. The albedo of the earth-atmospheric system increased during the warm Holocene Optimal but decreased during the last glacial period. During Heinrich cooling events, the cooling effect of dust aerosols was lower and did not reduce the air temperature of the earth system. It is possible to estimate the climate effect of dust aerosol in past by using the grain size distribution and the settlement velocity of loess-paleosol formations. CLIMATE CHANGE IN THE BLACK SEA CORRIDOR DURING THE UPPER PALEOLITHIC TRANSITION, LATE GLACIAL MAXIMUM AND OSCILLATING WARM-COLD PRE-BOREAL EVENTS
during warmer Allerod-Bölling events, providing further evidence for forest refugia in the western Pontic mountains. POLLEN-BASED RECONSTRUCTION OF VEGETATION AND ENVIRONMENTS IN THE VERKHOYANSK MOUNTAINS REGION (SIBERIA, RUSSIA) DURING THE PAST 50 KA Stefanie Müller. Freie Universität Berlin, Institute of Geological , Germany E-mail address: [email protected]
We present a detailed radiocarbon-dated 936 cm long pollen record from Lake Billyakh (6517’N, 126 47’E; 340 m a.s.l.) situated in the western part of the Verkhoyansk Mountains. A set of 53 surface pollen samples representing tundra, cold-deciduous forest and taiga communities was collected in Yakutia to verify the accuracy of the quantitative biome reconstruction method and to obtain a more precise attribution of the identified pollen taxa to the main regional biomes. The adjusted method is applied to the pollen record from Lake Billyakh to gain an objective reconstruction of vegetation and environments since about 50.7 ka BP. The results of both approaches suggest that herbaceous tundra and steppe communities dominated the area from 50.7 to 13.5 ka BP. A relative high content of taxa representing shrub tundra communities and the presence of larch pollen recorded prior to 31 ka and after 13.5 ka BP likely indicate interstadial climate amelioration associated with the middle and latest parts of the last glacial. Increasing pollen percentages of herbaceous taxa around 12 ka BP suggests broader distribution of drier communities in response to the colder and drier than present climate of the Younger Dryas. The onset of the Holocene is marked by the highest values of shrub taxa. Pollen percentages of arboreal taxa increase gradually and reach maximum values after 7 ka BP mainly reflecting the spread of Pinus sylvestris in central Yakutia as a response to the mid-Holocene climatic optimum. The most striking feature of the pollen record is the quasicontinuous presence of larch, shrubby birch and alder pollen throughout the whole record suggesting that larch possibly survived in locally favorable environments in the study region during the last 50 ka BP. Noticeable variations in larch pollen percentages point to multiple short-term warming episodes, which might be synchronous with the North Atlantic Dansgaard-Oeschger events. HIGH-RESOLUTION DIRECT CHEMICAL ANALYSIS OF DUST IN FROZEN ICE CORES BY CRYO-CELL LASER-ABLATION ICPMS
Peta Mudie. Memorial University Newfoundland, Canada
Wolfgang Muller. Royal Holloway University of London, United Kingdom
E-mail address: [email protected]
E-mail address: [email protected]
The history of climate and sea level change in the Black Sea region and its impact on the evolution of modern human populations over the past ca. 50,000 cal ybp is of salient importance to archaeologists and paleoclimatologists. A major question asks why and how early modern humans could displace Neanderthals who successfully occupied periglacial environments from 400 – 40 kaBP, but disappeared following a major volcanigenic interval in the eastern Mediterranean around 40 kaBP. Palynological studies of AMS shell-dated sediment cores from the western Black Sea (MAR 98-04) and eastern Marmara Sea (MAR 98-07, 98-012, MAR 94-05 and MAR2-89) provide a semi-continuous centennial-scale record of the vegetation, paleoclimate and paleohydrology for the time interval from around 45,000 to 11,703 cal ybp. Despite uncertainty about the exact age of the oldest mollusk shell dates, pollen records support interpretations that the a major climatic deterioration (“volcanic winter”) followed the volcanic event at the beginning of HS-4, followed by an amelioration and return of mesic forest by 34,963 cal ybp until shortly after D-O 3 at 27,931 cal bp. During this “volcanic winter”, the Black and Marmara seas supported different brackish-fresh water floras. New studies are focusing on palynological records of climate variability in the Marmara Sea region during the Paleolithic – Mesolithic late glacial and pre-Boreal interval from 30,490 -11,702 cal ybp, including the intervals correlative with HS 3 – 1 and GIS 5 – 1. Initial results show the interval from ca. 22,865 – 15,600 ca ybp was a largely cold, dry steppe/macchi landscape, but forest vegetation with deciduous oaks (Quercus) and chestnut (Castanea) trees rapidly appeared
High-latitude ice cores have become the master records of Pleistocene climate variability. Especially the high-resolution data from Greenland reveal a remarkably change:able glacial climate, and these rapid climate oscillations have recently been shown to take place within a few years only. The relative sequence of proxy records of dust, temperature or greenhouse gases allows identification of potential cause-effect relationships. For this to be successful, palaeoclimate information must be extracted at the highest possible, i.e. sub-annual, resolution. We present a new technique for controlled in-situ chemical analysis of ice cores at w0.1 mm resolution, which focuses on seasalt and dust tracers. It utilizes a custom-built, peltier-cooled cryo-sample holder fully compatible with a two-volume Laurin LA-cell, in turn coupled to a Resonetics M-50 excimer LA system and an Agilent 7500cs ICPMS. Using 3 x 5 cm strips of ice cores per sample holder, this setup allows elemental concentrations to be acquired using both depth-profiling along chains of spots and/or as continuous lateral profiles. Seasalt or dust tracers such as Mg, Ca, Al and Fe have limits of detection in the low(est) ppb-range, facilitated for Ca and Fe by using H2 as collision-cell gas in ICPMS. This facilitates 1) subseasonal and/or longer-term element concentration variations to be detected and 2) location of chemical impurities in recrystallizing ice to be identified. As such, Dansgaard-Oeschger (DO) events can be analyzed at unprecedented resolution. Initial data for last glacial maximum NGRIP ice overall show annual variability in Mg, Al, Fe, Ca compatible with annual cyclicity, but also remarkable small scale variability, which will be presented.