晚更新世以来奄美三角盆地黏土矿物的来源及其对古气候的指示  

Provenance of Clay Minerals in the Amami Sankaku Basin and Their Paleoclimate Implications Since Late Pleistocene

作　　者：刘华华[1,2] 蒋富清[1,3] 周烨[1,2] 李安春[1] 

机构地区：[1]中国科学院海洋研究所中国科学院海洋地质与环境重点实验室,山东青岛266071 [2]中国科学院大学,北京100049 [3]海洋国家实验室海洋地质过程与环境功能实验室,山东青岛266061

出　　处：《地球科学进展》2016年第3期286-297,共12页Advances in Earth Science

基　　金：国家自然科学基金项目"中新世以来奄美三角盆地的风尘记录及其对构造尺度东亚古气候的指示"(编号:41576050);国家海洋局"全球变化与海气相互作用"专项项目"西太平洋古气候研究"(编号:GASI-04-01-02)资助~~

摘　　要：对"国际大洋发现计划"(IODP)351航次U1438A孔晚更新世以来沉积物中黏土矿物的组成、含量及矿物学特征进行了分析。结果表明,U1438A孔中黏土矿物以伊利石为主,平均含量为57%;其次是蒙皂石,平均含量为26%;绿泥石的平均含量为14%;高岭石的含量最少,平均仅为3%。伊利石的结晶度较好(<0.4°Δ2θ),而且化学指数较低(<0.43),表明伊利石主要形成于干冷的气候环境。通过将U1438A孔黏土矿物组合特征与周边可能源区对比,并结合黏土矿物的结晶参数特征,认为蒙皂石主要来源于奄美三角盆地周边岛弧火山物质;伊利石、绿泥石和高岭石主要来自于亚洲大陆风尘。(伊利石+绿泥石)/蒙皂石比值阶段性增加与亚洲大陆晚更新世以来变干冷的趋势是一致的。(伊利石+绿泥石)/蒙皂石和(伊利石+绿泥石)/高岭石比值在冰期的高值,指示了冰期亚洲风尘物质输入的增加,这是对亚洲大陆冰期干旱化和东亚季风增强的响应。We analyzed the clay mineral assemblages,content and mineralogical characteristics of Hole U1438 A sediment recovered from Amami Sankaku Basin during International Ocean Discovery Program（ IODP） expedition 351. The results show that the clay minerals are mainly composed of illite（ average 57%）,smectite（ average 26%）,chlorite（ average 14%） and minor kaolinite（ average 3%）. The crystallinity of illite in all samples are good（ 0. 4 Δ° 2θ）,and the chemical indexes of illite in all samples are low（ 0. 4）. Both indicate that illite in Hole U1438 A formed in cold and dry climate. By comparing clay mineral assemblages of hole U1438 A and the potential sediment sources,we suggest that smectite be mainly derived from the volcanic materials around Amami Sankaku Basin. Illite,chlorite and kaolinite are mainly derived from the Asian dust. The ratios of（ illite ＋ chlorite） / smectite show a phased increase over the last 350 ka,which is consistent with the cold and drying trend of the Asian continent since late Pleistocene. The high ratios of（ illite ＋ chlorite） / smectite and（ illite ＋ chlorite） / kaolinite during glacial period indicate that much more Asian dust was input into the Amami Sankaku Basin,which are responded to the aridity of Asian continent and strengthened east Asian Monsoon during glacial period.

关 键 词：奄美三角盆地 黏土矿物 物源 古气候 

分 类 号：P736.212[天文地球—海洋地质]