楚科奇海陆坡ARC5-M06柱样晚更新世以来黏土矿物组成变化的古环境意义

PALEOENVIRONMENTAL SIGNIFICANCE OF CLAY MINERAL ASSEMBLAGES OF CORE ARC5-M06 ON THE CHUKCHI SEA CONTINENTAL SLOPE SINCE LATE PLEISTOCENE

对中国第5次北极科学考察采自楚科奇海陆坡的ARC5-M06柱样进行粒度、冰筏碎屑、碎屑矿物、黏土矿物、岩心XRF扫描、沉积物颜色分析,初步建立了楚科奇海陆坡晚更新世MIS3期以来的沉积地层框架。ARC5-M06柱黏土矿物组合类型为伊利石(66%)-绿泥石(22%)-高岭石(9%)-蒙皂石(3%)组合,与北冰洋边缘海表层沉积物黏土矿物组合类型对比表明,MIS3期以来楚科奇海陆坡除MIS3期晚期黏土矿物陆源主要来自北美大陆的加拿大马更些河入海物质及少量太平洋水团携入的北美育空河入海物质外,其他时期均主要来自于东西伯利亚海的输入;自MIS2末次盛冰期以来,陆坡与海盆的黏土矿物源区发生了改变,陆坡主要来自于东西伯利亚海的输入,海盆主要来自于北美大陆物源输入,受波弗特海的输入影响较大。

A gravity core of ARC5-M06 was taken from the Chukchi Sea slope during the Fifth Chinese National Arctic Research Expedition in 2012.All samples were analysed for grain size,ice-raft detritus,clastic minerals,clay minerals,XRF scanning and sediment color features.The stratigraphic framework of the late Pleistocene of the core ARC5-M06 since Marine Isotope Stage（MIS）3was established by integration of IRD,color cycles,element cycles,as done previously for other cores.The clay mineral assemblages consist of illite,kaolinite and chlorite with small amount of smectite.Clay mineral assemblages in the core ARC5-M06 were compared with those in the adjacent marginal continental shelf to identify their provenance and transport processes during the Late Pleistocene.Based on the above studies,it is concluded that the clay mineral assemblages in the Chukchi Sea slope sediments were mainly from the East Siberia Sea during MIS3,but from the Mackenzie River in Canada and the Yukong River in the North America Continent through the Pacific water masses during late MIS3.And the clay minerals assemblages in the Chukchi Sea slope sediments were mainly from the the East Siberia Sea source input,but those in the Chukchi Sea basin sediments were mainly from the North American continent source input with much more from the Beaufort sea.