A study on phytoliths and their climate indexes is carried out from Homo erectus?cave deposits in HuluCave, Nanjing. Evidence shows that phytolith assemblages of the cave deposits are dominated by the cold resistant t...A study on phytoliths and their climate indexes is carried out from Homo erectus?cave deposits in HuluCave, Nanjing. Evidence shows that phytolith assemblages of the cave deposits are dominated by the cold resistant types with a lower warm index, reflecting an overall cold inclined climate. This possibly connects the cave deposits with glacial climate to a great extent, which is in accordance with thenorthern fauna revealed by fossil mammals and temperateclimate indicated by pollen assemblages. According to the distributional state of the phytoliths and their climate in-dexes on 4 profiles in the cave, it is revealed that profiles Ⅰand Ⅱ display certain cold/warm, and dry/wet fluctuations; profile Ⅲ shows a humid and cold condition with the high-est humility in the cave deposits; while profile Ⅳ indicates a possible quick accumulating process because of its stableclimate indexes except for its bottom and top.展开更多
Total 26 modern soil samples were collected from various regions under different climate conditions from tropical to arid temperate in China and systematically analyzed for their organic matters by GC/MS in order to e...Total 26 modern soil samples were collected from various regions under different climate conditions from tropical to arid temperate in China and systematically analyzed for their organic matters by GC/MS in order to evaluate climatic impacts on soil organic components. Abundant lipids molecules were recognized, including n-alkanes, n-alkenones, and long-chain branched alkanes. We find the pre- dominance of main peaks of long-chain n-alkanes (nC29, nC31, nC33) and short-chain ones (nC16, nC17, nC18) records information of soil generation in warm-humid and cold-dry regions. The proportion of n-alkanes (nC16+nC17+nC18) to (nC29+nC31+nC33) varies in good agreement with moisture-heat conditions and thus probably can serve as a new index for climate change. The ratios of C21-/nC22+, nC17/nC31 and (nC15+nC17+nC19) / ( nC27+nC29 +nC31) of n-alkanes, indicating respectively input ratios of lower bacterial alga, aquatic organisms, and higher plants and terraneous organisms, co-vary well in different climate regions from forest to grassland and desert, suggesting that they have also reflected the difference of climates between monsoon region and inland one. The C21-/C22+ ratio of n-alkan-2-one records largely the discrepancy of temperature from north to south of China bordered by the Qinling Mountains, but less humidity. The C21-/C22+ ratio of n-alkan-3-ones changes well with climatic factors, such as tem- perature and humidity. The biogenic source of series A-D long-chain branched alkanes may be derived from some kinds of special epiphyte that most likely live in weak oxic-anoxic and moisture-heat envi- ronments, suggesting their distribution record as well some information on climatic change. All these researches demonstrate that the distributions of lipids molecules in modern soils in China record well signals of climates from quite different climatic regions, and can serve as important climatic proxies to reveal climatic change over China.展开更多
文摘A study on phytoliths and their climate indexes is carried out from Homo erectus?cave deposits in HuluCave, Nanjing. Evidence shows that phytolith assemblages of the cave deposits are dominated by the cold resistant types with a lower warm index, reflecting an overall cold inclined climate. This possibly connects the cave deposits with glacial climate to a great extent, which is in accordance with thenorthern fauna revealed by fossil mammals and temperateclimate indicated by pollen assemblages. According to the distributional state of the phytoliths and their climate in-dexes on 4 profiles in the cave, it is revealed that profiles Ⅰand Ⅱ display certain cold/warm, and dry/wet fluctuations; profile Ⅲ shows a humid and cold condition with the high-est humility in the cave deposits; while profile Ⅳ indicates a possible quick accumulating process because of its stableclimate indexes except for its bottom and top.
基金Supported by the was co-supported by the National Basic Research Program of China (Grant No. 2005CB422001)NSFC (Grant Nos. 40672123 and 40421101) the President Fund of the Chinese Academy of Sciences
文摘Total 26 modern soil samples were collected from various regions under different climate conditions from tropical to arid temperate in China and systematically analyzed for their organic matters by GC/MS in order to evaluate climatic impacts on soil organic components. Abundant lipids molecules were recognized, including n-alkanes, n-alkenones, and long-chain branched alkanes. We find the pre- dominance of main peaks of long-chain n-alkanes (nC29, nC31, nC33) and short-chain ones (nC16, nC17, nC18) records information of soil generation in warm-humid and cold-dry regions. The proportion of n-alkanes (nC16+nC17+nC18) to (nC29+nC31+nC33) varies in good agreement with moisture-heat conditions and thus probably can serve as a new index for climate change. The ratios of C21-/nC22+, nC17/nC31 and (nC15+nC17+nC19) / ( nC27+nC29 +nC31) of n-alkanes, indicating respectively input ratios of lower bacterial alga, aquatic organisms, and higher plants and terraneous organisms, co-vary well in different climate regions from forest to grassland and desert, suggesting that they have also reflected the difference of climates between monsoon region and inland one. The C21-/C22+ ratio of n-alkan-2-one records largely the discrepancy of temperature from north to south of China bordered by the Qinling Mountains, but less humidity. The C21-/C22+ ratio of n-alkan-3-ones changes well with climatic factors, such as tem- perature and humidity. The biogenic source of series A-D long-chain branched alkanes may be derived from some kinds of special epiphyte that most likely live in weak oxic-anoxic and moisture-heat envi- ronments, suggesting their distribution record as well some information on climatic change. All these researches demonstrate that the distributions of lipids molecules in modern soils in China record well signals of climates from quite different climatic regions, and can serve as important climatic proxies to reveal climatic change over China.
