- Email: [email protected]
Magnetic properties of aeolian deposits in Paleolithic sites in Korea and correlation with the Chinese loess-paleosol sequence
Abstracts / Quaternary International 279-280 (2012) 121–232
(Hayashi et al., 2010a,b), show that continuous appearances of Quercus subgenus Cyclobalanopsis pollen with Lagerstroemia pollen are recognized only in the last interglacial period. Comparison with those pollen records, the peat sediment in the Mizukiri site is suggested to represent the vegetation change during the end of the last interglacial to the earliest part of the last glacial (MIS 5e to 5d). PALEOCLIMATE RECONSTRUCTION FOR THE HOLOCENE AND THE LAST GLACIAL PERIOD BASED ON ENVIRONMENTAL MAGNETIC RECORD FROM LAKE BIWA, CENTRAL JAPAN Akira Hayashida. Doshisha University, Japan
191
the Chinese samples. It is likely that degree of the silicate weathering and the soil formation process were more extended than the arid inland China, probably due to higher precipitation in the Korean Peninsula. Despite of the higher degree of pedogenesis, the variation of magnetic susceptibility can be correlated with the Chinese loess-paleosol sequences. This correlation is partly confirmed by occurrence of volcanic grains, which were identified as widespread tephra deposits from the Japanese Islands. Thus detailed stratigraphic analysis of these deposits contributes to correlation and chronology of the Paleolithic sites in Korea. STILL A PUZZLE: THE ORIGINS OF EARLY FARMING IN NORTHWESTERN ZIMBABWE
E-mail address: [email protected]
Gary Haynes. University of Nevada-Reno, United States Lake Biwa, located in central Japan, contains a thick sedimentary sequence deposited in lacustrine or fluvial environments during the Pleistocene. Tephrochronology and magnetostratigraphic analysis of deep-drilling cores from the central basin showed that about 800-m thick sediment has been deposited for the last 1.3 m.y. The uppermost 250-m clay unit has provided important paleoclimate records, which can be correlated to major glacial-interglacial cycles for the last 0.45 m.y. We demonstrate that anhysteretic remanent magnetization (ARM), which is a measure of magnetic mineral content in sediment, provides a good proxy of hydrological changes around Lake Biwa since the last glacial period. Our previous study on a piston-core recovered in 1995 revealed that the ARM increases in the post-glacial interval and that the variation in the lower part is likely linked to millennial-scale climate changes during the last glacial period. This finding was confirmed by analysis of new piston-cores recovered from other sites in 2007. The ARM records reproducibly extend back to 46 ka, featuring major interstadials of Dansgaard-Oeschger cycles, the Heinrich events and climate changes during the Holocene. The ARM data are consistent with variation of total organic carbon content and vegetation history inferred from pollen analysis. We interpret that the increased ARM represents enhanced precipitation probably associated with higher monsoon activity. The ARM record from Lake Biwa is apparently synchronized with the oxygen isotope records from stalagmites of Hulu Cave in China and the Greenland ice core (NGRIP), suggesting that the monsoon activity is interlinked with regional and global climatic changes. On-going analysis of the samples from deep drilling sites shows that the ARM data also provide paleoclimate records for the older glacial-interglacial cycles. We therefore expect that magnetic analysis of Lake Biwa sediment provides new insights of the East Asian monsoon evolution since the Middle Pleistocene. MAGNETIC PROPERTIES OF AEOLIAN DEPOSITS IN PALEOLITHIC SITES IN KOREA AND CORRELATION WITH THE CHINESE LOESS-PALEOSOL SEQUENCE Akira Hayashida. Doshisha University, Japan E-mail address: [email protected]
Long-standing investigation of terrestrial wind-blown silt deposit in the Chinese Loess Plateau revealed that contrasting magnetic properties of loess and paleosol layers provide a means of correlation of the loess sequences to the marine oxygen isotope record and high-resolution chronology. Although thickness of the loess deposits distinctly decreased in east, aeolian deposits resembling to the Chinese loess-paleosol are sporadically distributed in the Korean Peninsula. We have investigated magnetic properties of the aeolian deposits at several localities in Korea, including Paleolithic sites at Chongokni in the Imjin/Hantan River Basins and at Mansuiri near Cheongju City. At both sites, low-field magnetic susceptibility showed increased values at horizons of paleosol layers characterized by reddish brown color and soil cracks, although the susceptibility peaks of the older paleosols are obscured. High values of the frequency dependence suggest that formation of fine magnetite or maghemite grains in pedogenic processes, as known for the Chinese loesspaleosol sequences. It is also noticeable that superparamagnetic minerals are dominant even in the less-weathered intervals between the paleosol layers. Preliminary results of our geochemical analysis show that these sediments are characterized by chemical index of alteration higher than
E-mail address: [email protected]
This paper describes a project to define the origins of agropastoralism in northwestern Zimbabwe, Africa. The study area is in a probable corridor of cultural diffusion or human movement from central Africa towards the southern tip of the continent. Ongoing archeological and paleoenvironmental studies will provide a clearer picture of the transition from foraging to farming in the region. Exacavations in stratified sites indicate Later Stone Age (LSA) hunter-gatherers with microlithic technology utilized a wide array of local and extra-local resources 3,600 BP and later, but at w2,300 BP deposition lessened (from w1 cm/10 yrs to w1 cm/ 150yrs). One site of the Early Farming Community (EFC) period, located near the stratified LSA sites, has been dated w2,000 BP, although it was originally dated w1,100 BP when first found. The site contains bones of cattle and wild animals, sherds of Gokomere ware, slag from iron-smelting, and dhaka from hut construction. Recent re-examination and coring of the locality indicate this EFC village occupied an extensive area. The spatial extent and recent near-doubling of the age based on an AMS date on charcoal from a ceramic sherd may indicate a lengthy period of occupation. Not far away, relict dunes of Kalahari sand contain buried lenses of charcoal dated w1,800 to 2,700 BP, suggesting wetter (and probably warmer) conditions producing relatively more standing fuel in this interval, around the time when agropastoralism took hold. Efforts to recover paleoenvironmental proxy data continue to emphasize geoarcheological testing of streamcuts, drainage ways, and undisturbed sediments in basins and dunefields. Still missing is the archeological link between the youngest stratified record of forager behavior at 2,300 BP and the oldest record of farmers at 2,000 BP. PALAEOLIMNOLOGY GUIDES MANAGEMENT OF THE RAMSAR LISTED COORONG AND LOWER LAKES IN SOUTH AUSTRALIA Deborah Haynes. University of Adelaide, Australia E-mail address: [email protected]
The Coorong, with Lakes Alexandrina and Albert (the Lower Lakes) form an extensive wetland complex of Holocene age at the terminus of the MurrayDarling Basin. The Lower Lakes are large, freshwater bodies that discharge to the Indian Ocean through the Murray Mouth. The Coorong is an elongate saline wetland comprised of a North and South Lagoon, extending southeast from the Murray Mouth that receives inflow from the south-east catchment. Declared wetlands of international significance under the Ramsar protocol in 1985, their condition at that time, however, did not reflect their pre-European ecological status. This research, unusual in Australian palaeoecology, was funded by the State Government and was designed to specifically address questions about the ecological character of these wetlands. The outcomes have been explicitly considered in the formulation of management strategies. The research utilised diatom-based palaeolimnology to investigate:
1. The natural variability in water quality during the Holocene; 2. The nature of any anthropogenic impacts on water quality; and 3. The extent of the estuary in the Lower Lakes and The Coorong. The diatom evidence indicates that Lower Lakes were estuarine at the culmination of sea level transgression w7 ka BP. Following sea level
(Hayashi et al., 2010a,b), show that continuous appearances of Quercus subgenus Cyclobalanopsis pollen with Lagerstroemia pollen are recognized only in the last interglacial period. Comparison with those pollen records, the peat sediment in the Mizukiri site is suggested to represent the vegetation change during the end of the last interglacial to the earliest part of the last glacial (MIS 5e to 5d). PALEOCLIMATE RECONSTRUCTION FOR THE HOLOCENE AND THE LAST GLACIAL PERIOD BASED ON ENVIRONMENTAL MAGNETIC RECORD FROM LAKE BIWA, CENTRAL JAPAN Akira Hayashida. Doshisha University, Japan
191
the Chinese samples. It is likely that degree of the silicate weathering and the soil formation process were more extended than the arid inland China, probably due to higher precipitation in the Korean Peninsula. Despite of the higher degree of pedogenesis, the variation of magnetic susceptibility can be correlated with the Chinese loess-paleosol sequences. This correlation is partly confirmed by occurrence of volcanic grains, which were identified as widespread tephra deposits from the Japanese Islands. Thus detailed stratigraphic analysis of these deposits contributes to correlation and chronology of the Paleolithic sites in Korea. STILL A PUZZLE: THE ORIGINS OF EARLY FARMING IN NORTHWESTERN ZIMBABWE
E-mail address: [email protected]
Gary Haynes. University of Nevada-Reno, United States Lake Biwa, located in central Japan, contains a thick sedimentary sequence deposited in lacustrine or fluvial environments during the Pleistocene. Tephrochronology and magnetostratigraphic analysis of deep-drilling cores from the central basin showed that about 800-m thick sediment has been deposited for the last 1.3 m.y. The uppermost 250-m clay unit has provided important paleoclimate records, which can be correlated to major glacial-interglacial cycles for the last 0.45 m.y. We demonstrate that anhysteretic remanent magnetization (ARM), which is a measure of magnetic mineral content in sediment, provides a good proxy of hydrological changes around Lake Biwa since the last glacial period. Our previous study on a piston-core recovered in 1995 revealed that the ARM increases in the post-glacial interval and that the variation in the lower part is likely linked to millennial-scale climate changes during the last glacial period. This finding was confirmed by analysis of new piston-cores recovered from other sites in 2007. The ARM records reproducibly extend back to 46 ka, featuring major interstadials of Dansgaard-Oeschger cycles, the Heinrich events and climate changes during the Holocene. The ARM data are consistent with variation of total organic carbon content and vegetation history inferred from pollen analysis. We interpret that the increased ARM represents enhanced precipitation probably associated with higher monsoon activity. The ARM record from Lake Biwa is apparently synchronized with the oxygen isotope records from stalagmites of Hulu Cave in China and the Greenland ice core (NGRIP), suggesting that the monsoon activity is interlinked with regional and global climatic changes. On-going analysis of the samples from deep drilling sites shows that the ARM data also provide paleoclimate records for the older glacial-interglacial cycles. We therefore expect that magnetic analysis of Lake Biwa sediment provides new insights of the East Asian monsoon evolution since the Middle Pleistocene. MAGNETIC PROPERTIES OF AEOLIAN DEPOSITS IN PALEOLITHIC SITES IN KOREA AND CORRELATION WITH THE CHINESE LOESS-PALEOSOL SEQUENCE Akira Hayashida. Doshisha University, Japan E-mail address: [email protected]
Long-standing investigation of terrestrial wind-blown silt deposit in the Chinese Loess Plateau revealed that contrasting magnetic properties of loess and paleosol layers provide a means of correlation of the loess sequences to the marine oxygen isotope record and high-resolution chronology. Although thickness of the loess deposits distinctly decreased in east, aeolian deposits resembling to the Chinese loess-paleosol are sporadically distributed in the Korean Peninsula. We have investigated magnetic properties of the aeolian deposits at several localities in Korea, including Paleolithic sites at Chongokni in the Imjin/Hantan River Basins and at Mansuiri near Cheongju City. At both sites, low-field magnetic susceptibility showed increased values at horizons of paleosol layers characterized by reddish brown color and soil cracks, although the susceptibility peaks of the older paleosols are obscured. High values of the frequency dependence suggest that formation of fine magnetite or maghemite grains in pedogenic processes, as known for the Chinese loesspaleosol sequences. It is also noticeable that superparamagnetic minerals are dominant even in the less-weathered intervals between the paleosol layers. Preliminary results of our geochemical analysis show that these sediments are characterized by chemical index of alteration higher than
E-mail address: [email protected]
This paper describes a project to define the origins of agropastoralism in northwestern Zimbabwe, Africa. The study area is in a probable corridor of cultural diffusion or human movement from central Africa towards the southern tip of the continent. Ongoing archeological and paleoenvironmental studies will provide a clearer picture of the transition from foraging to farming in the region. Exacavations in stratified sites indicate Later Stone Age (LSA) hunter-gatherers with microlithic technology utilized a wide array of local and extra-local resources 3,600 BP and later, but at w2,300 BP deposition lessened (from w1 cm/10 yrs to w1 cm/ 150yrs). One site of the Early Farming Community (EFC) period, located near the stratified LSA sites, has been dated w2,000 BP, although it was originally dated w1,100 BP when first found. The site contains bones of cattle and wild animals, sherds of Gokomere ware, slag from iron-smelting, and dhaka from hut construction. Recent re-examination and coring of the locality indicate this EFC village occupied an extensive area. The spatial extent and recent near-doubling of the age based on an AMS date on charcoal from a ceramic sherd may indicate a lengthy period of occupation. Not far away, relict dunes of Kalahari sand contain buried lenses of charcoal dated w1,800 to 2,700 BP, suggesting wetter (and probably warmer) conditions producing relatively more standing fuel in this interval, around the time when agropastoralism took hold. Efforts to recover paleoenvironmental proxy data continue to emphasize geoarcheological testing of streamcuts, drainage ways, and undisturbed sediments in basins and dunefields. Still missing is the archeological link between the youngest stratified record of forager behavior at 2,300 BP and the oldest record of farmers at 2,000 BP. PALAEOLIMNOLOGY GUIDES MANAGEMENT OF THE RAMSAR LISTED COORONG AND LOWER LAKES IN SOUTH AUSTRALIA Deborah Haynes. University of Adelaide, Australia E-mail address: [email protected]
The Coorong, with Lakes Alexandrina and Albert (the Lower Lakes) form an extensive wetland complex of Holocene age at the terminus of the MurrayDarling Basin. The Lower Lakes are large, freshwater bodies that discharge to the Indian Ocean through the Murray Mouth. The Coorong is an elongate saline wetland comprised of a North and South Lagoon, extending southeast from the Murray Mouth that receives inflow from the south-east catchment. Declared wetlands of international significance under the Ramsar protocol in 1985, their condition at that time, however, did not reflect their pre-European ecological status. This research, unusual in Australian palaeoecology, was funded by the State Government and was designed to specifically address questions about the ecological character of these wetlands. The outcomes have been explicitly considered in the formulation of management strategies. The research utilised diatom-based palaeolimnology to investigate:
1. The natural variability in water quality during the Holocene; 2. The nature of any anthropogenic impacts on water quality; and 3. The extent of the estuary in the Lower Lakes and The Coorong. The diatom evidence indicates that Lower Lakes were estuarine at the culmination of sea level transgression w7 ka BP. Following sea level