Late Quaternary glacial cycle and precessional period of clay mineral assemblages in the Western Pacific Warm Pool  

作　　者：WU JiaWang LIU ZhiFei ZHOU Chao 

机构地区：[1]State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China

出　　处：《Chinese Science Bulletin》2012年第28期3748-3760,共13页

基　　金：supported by the National Natural Science Foundation of China (40925008 and 91128206);the National Basic Research Program of China(2007CB815906)

摘　　要：Variability of clay mineral assemblages in the Western Pacific Warm Pool(WPWP) over the past 370 ka shows the prominent glacial-interglacial cyclicity.Smectite(62%-91%) is the dominant clay mineral,with decreased contents during interglacials while increased in glacials.In contrast,variations in chlorite(4%-21%),illite(4%-12%),and kaolinite(2%-10%) share a similar pattern with higher contents during interglacials than glacials,mirroring to that of smectite.The results indicate that the smectite-dominated clay minerals derive mainly from the river detrital inputs of New Guinea.The glacial-interglacial cycle of clay mineral assemblages well correspond to the fluctuation of sea level.When the sea level was low,the river materials can travel more easily across the narrow shelf off the island of New Guinea,inject directly into the subsurface currents flowing westwards,then merge into the Equatorial Undercurrent(EUC),and eventually deposit on the central part of WPWP.Precessional periods of the smectite content indicate the intensity of mechanical erosion in its provenance of New Guinea,responding to the river runoff and precipitation,and this could also be linked to the meridional migration of the Intertropical Convergence Zone(ITCZ).Variability of clay mineral assemblages in the Western Pacific Warm Pool （WPWP） over the past 370 ka shows the prominent glacial-interglacial cyclicity. Smectite （62%-91%） is the dominant clay mineral, with decreased contents during interglacials while increased in glacials. In contrast, variations in chlorite （4%-21%）, illite （4%-12%）, and kaolinite （2%-10%） share a similar pattern with higher contents during interglacials than glacials, mirroring to that of smectite. The results indicate that the smec- tite-dominated clay minerals derive mainly from the river detrital inputs of New Guinea. The glacial-interglacial cycle of clay mineral assemblages well correspond to the fluctuation of sea level. When the sea level was low, the river materials can travel more easily across the narrow shelf off the island of New Guinea, inject directly into the subsurface currents flowing westwards, then merge into the Equatorial Undercurrent （EUC）, and eventually deposit on the central part of WPWP. Precessional periods of the smectite content indicate the intensity of mechanical erosion in its provenance of New Guinea, responding to the river runoff and precipitation, and this could also be linked to the meridional migration of the Intertropical Convergence Zone （ITCZ）.

关 键 词：西太平洋暖池 冰期旋回 矿物组合 岁差周期 晚第四纪 黏土 河流径流量 粘土矿物 

分 类 号：P732[天文地球—海洋科学] P532