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贝加尔钻探计划(BDP)中的96-1井位于贝加尔湖中央的科学湖脊,1996年冬从位于332m水深以下的钻井采样。钻孔从湖底向下深200m,根据古地磁资料,钻孔年代推测为5.1Ma。 Tsuga,Lepidobalanus,Ulmaceae,Tilia和Corylus发现于钻孔的下部约60m。因为这些化石花粉目前在贝加尔湖地区己经消失,说明该钻孔上部的气候比下部的冷。因此,第四纪的气候比晚第三纪的更为干冷。 在亚北极的西伯利亚,冰期时期以草本植物花粉占统治地位,花粉浓度较低,而在间冰期时期以木本花粉为主,花粉浓度较高。在间冰期时期硅藻及有机物总量增加,潮湿度(wet density)及氧同位素比率都降低。相反,在冰期时期硅藻含量及有机物总量降低,而潮湿度(wet dendity)和氧同位素比率都增加。
Well 96-1 in the Baikal Drilling Program (BDP) is located in the Science Lake Ridge in the center of Lake Baikal and was drilled from a well below 332 m deep in the winter of 1996. Drilling down from the bottom of the lake 200m, according to paleomagnetic data, presumed to be 5.1Ma drilling years. Tsuga, Lepidobalanus, Ulmaceae, Tilia and Corylus were found about 60 m below the borehole. Because these fossil pollens have now disappeared in the Baikal region, the upper part of the borehole is cooler than the lower part. As a result, the Quaternary climate was drier than the late Tertiary. In sub-Arctic Siberia, herbaceous pollen dominates during the Ice Age with low pollen concentration, whereas in the interglacial period, woody pollen was predominant and pollen concentration was higher. During the interglacial period, the total amount of diatoms and organic matter increased, and the wet densities and oxygen isotope ratios decreased. In contrast, diatoms and total organic matter decreased during the Ice Age, while both wet dendity and oxygen isotope ratios increased.