Paleoenvironmental Study by the Mineralogical and Geochemical Analyses of the Deep-Sea Drilling Cores

对墨西哥湾、阿拉伯海和孟加拉扇的钻探钻探和钻探岩芯进行了矿物学和地球化学研究。这项研究的目的是从这些岩心的矿物学和地球化学特征中阐明古环境因素。得到的结果有明显的不同。例如，墨西哥湾的沉淀柱以丰富的蒙脱石和高岭石为特征。阿拉伯海沉积物的主要特征是坡缕石的存在。自早中新世以来，孟加拉扇的沉积物确实具有不同的粘土矿物组成。影响粘土矿物组成的因素有地质、成岩改造、土壤形成、河流径流、海流、气候等。例如，墨西哥湾的沉淀柱受密西西比河径流的影响很大，密西西比河是致岩矿物的主要来源。T…的沉积物更多的孟加拉球迷从起源于喜马拉雅山脉的Burahmaputa获得了大量的碎屑矿物。作者指出，喜马拉雅运动与早中新世以来粘土矿物组成的垂向变化密切相关。阿拉伯海沉积物中凹凸棒石分布在不同比例的沉积柱中，其比例随地质时代的变化而变化。K/Al、Ti/Al、Fe/Al、Cr/Al、Zn/Al、Ni/Al等地球化学参数。沉积柱中的硅铝比、磷铝比、锶钙比、铜铝比反映了地质历史时期的环境变化，反映了古环境事件。研究表明，沉积柱中粘土矿物学与地球化学之间的关系不一定是相互认识的，但起着共同的作用。例如，沉积柱中的Fe/Al、Cr/Al、Ni/Al和Zn/Al比值表明，除粘土矿物外，还含有其他造岩矿物，并与沉积环境的变化密切相关。较少

Mineralogical and geochemical studies carried out on the DSDP and ODP cores from the Gulf of Mexico, the Arabian Sea, and the Bengal Fan. The purpose of this study is to clarify the paleoenvironmental factors from the mineralogical and geochemical characteristics of these cores. The results obtained differ conspicuously. For example, the sediment columns of the Gulf of Mexico is characterized by the abundance of smectite and kaolinite. The sediments of the Arabian Sea is essentially characterized by the presence of palygorskite. The sediments of the Bengal Fan have indeed variable clay mineral compositions since the Early Miocene. The factors influencing the clay mineral compositions are such as geology, diagenetic transformation, soil formation, river runoff, sea currents, and climatology so on. For example, the sediment columns of the Gulf of Mexico are greatly influenced by the river runoff from the Mississippi which is the major source of the lithogenic minerals. The sediments of t … More he Bengal Fan have received a tremendus quantity of clastic minerals from the Burahmaputra which originates from the Himalayas. The authors point that the movements of the Himalayas are closely related to the vertical change in clay mineral compositions since the Early Miocene. The Arabian Sea sediments contain the palygorskite in various proportion of sedimentary columns and the proportion changes with geological time. In the same manner, the geochemical parameters such as the ratios of K/Al, Ti/Al, Fe/Al, Cr/Al, Zn/Al, Ni/Al. Si/Al, P/Al, Sr/Ca, and Cu/Al in sedimentary columns indicate the changes of environments in geological past and suggest the paleoenvironmental events. The present study shows that the relationshie between the clay minealogy and geochemistry in sedimentary columns is not neccessarily recognized each other but play a comelementary role. For example, the ratios of Fe/Al, Cr/Al, Ni/Al, and Zn/Al in sedimentary columns suggest that other lithogenic minerals except clay minerals are contained and closely related to the changes of sedimentary environments. Less