摘要: 北大西洋地区是全球环境变化研究的热点区域。对IODP(国际综合大洋钻探计划)北大西洋306航次U1313站位深海沉积物陆源组分的粒度分析发现,陆源组分主要由黏土(粒径小于4μm)和极细粉沙(4~8μm)两个粒级构成,以黏土为主,分选性较差。通过与钙质超微化石、有孔虫等生物化石资料和同位素测年等技术相结合,重建了古气候的变化情况:(1)2.415~1.897 Ma BP,气候呈周期性波动;(2)1.897~1.640 Ma BP,气候变化相对平缓;(3)1.640~1.471 Ma BP,气候波动剧烈且频繁。粒度指标所反映的几次粗颗粒增多事件与早更新世期间数次气候变冷事件的发生时间一致。1.6 Ma BP前后粒度参数的突然变化,可能与地球轨道参数的改变有关,进一步证实地球轨道参数作为气候系统外部驱动力的重要性。
关键词:
早更新世,
北大西洋,
深海沉积物,
陆源组分,
粒度特征
Abstract: The North Atlantic is the key region in researches of global climate change.In this paper,we have done grain-size analysis with the terrigenous constituents of deep-sea sediments from the IODP(Integrated Ocean Drilling Program) Site U1313,the results show that the terrigenous constituents mainly composed of clay and very fine slit,and the fine-grain materials(grain diameter less than 4μm)is a main component.Combining with palaeobiological data and stable isotope dating,we reconstruct the evolution of paleoclimate,the palaeoclimate in the North Atlantic during the Early Pleistocene is divided into three phases:(1)2.415~1.897 Ma BP,climate fluctuated periodically;(2)1.897~1.640 Ma BP,the climate changed gently;(3)1.640~1.471 Ma BP,climate changed violently and frequently.The events of grain size suddenly increased correspond to the cold events during the Early Pleistocene.The suddenly change of grain size parameter nearby 1.6 Ma BP possibly linked to the earth orbital parameters change,which shows the importance of orbital parameter as external driving force to earth climate.
Key words:
Early Pleistocene,
North Atlantic,
deep-sea sediment,
terrigenous constituents,
grain size characteristics
中图分类号:
翟秋敏, 郭志永, 李磊, 王海荣. 北大西洋IODP U1313站位早更新世深海沉积物陆源组分粒度特征及其环境意义*[J]. 古地理学报, 2012, 14(2): 261-268.
Zhai Qiumin, Guo Zhiyong, Li Lei, Wang Hairong. Grain size characteristics and their environmental significance of terrigenous constituents in deep-sea sediments at IODP Site U1313 in North Atlantic during the Early Pleistocene[J]. JOURNAL OF PALAEOGEOGRAPHY, 2012, 14(2): 261-268.