北冰洋西部楚科奇海盆晚第四纪生源沉积物及其古海洋学意义

通过北冰洋西部楚科奇海盆M03孔晚第四纪以来生源沉积物，有孔虫丰度和冰筏碎屑(Ice．Rafted Detritus，IRD)的综合研究表明，海洋氧同位素(Marine Isotope Stage，MIS)7期以来，碳酸钙(CaCO )含量和浮游有孔虫丰度在间冰期的增加和冰期的降低，分别指示大西洋水输入的加强和减弱。而有机碳(TOC)和生源蛋白石(Biogenic Opa1)含量的变化可能主要与输入到海底的TOC降解和Opal溶解作用与底层水中的溶解氧有关。间冰期低的TOC和Opal含量可能反映楚
科奇海盆海冰覆盖减少，营养盐供给多，表层生产力增加，通气作用好，底层水富氧，降解和溶解作用增强，保存在沉积物中的TOC和Opal减少；而冰期相对高的TOC和Opal含量可能反映楚科奇海盆海冰覆盖时间较长，营养盐供给少，表层生产力较低，通气作用差，底层水少氧，降解和溶解作用减弱，保存在沉积物中的TOC和Opal增多。

LATE QUATERNARY BIOGENIC SEDIMENTS AND THEIR PALEOCEANOGRAPHIC IMPLICATIONS IN THE CHUKCHI BASIN, WESTERN ARCTIC OCEAN

An integrated study was carried out on biogenic sediments, foraminiferal abundance and icerafted detritus (IRD) of core M03 in the Chukchi Basin, western Arctic Ocean to investigate preservation conditions of biogenic components and environmental changes during the late Quaternary. Our results show that since Marine Isotope Stage (MIS) 7, calcium carbonate (CaCO_3)and planktonic foraminiferal abundance increased and decreased during interglacial and glacial periods, respectively, which indicate the Atlantic Water input intensified and weakened in those intervals. However, variations in total organic carbon (TOC) and biogenic opal (opal) contents were primarily associated with the degradation and dissolution of TOC and opal transported to on seafloor and dissolved oxygen level in bottom water. During interglacial periods, low TOC and opal contents suggest that although lessening sea ice coverage and more nutrition supply enhanced sea surface productivity, well-ventilated and oxygenated bottom water, together with reinforcing degradation and dissolution, resulted in decreasing TOC and opal contents preserved in the sediments. During glacial periods, high TOC and opal contents suggest that although extensive sea ice coverage and short of nutrition supply reduced sea surface productivity, bad-ventilated and anoxic bottom water, together with weakening degradation and dissolution, led to increasing TOC and opal contents preserved in the sediments.