西菲律宾海沉积物矿物组合及其地质意义

THE MINERAL ASSEMBLAGES IN THE SEDIMENTS IN THE WEST PHILLIPPINE SEA AND THEIR GEOLOGICAL IMPLICATION

用X射线衍射法测试了1988年取自西菲律宾海3个柱样共52个沉积物样品的矿物组成。结果表明，沉积物中主要矿物为方解石、石英、斜长石和钾长石，次要矿物为高岭石、绿泥石、角闪石、斜发沸石、水云母、蒙脱石和滑石。划分出两类矿物组合：（1）方解石＋石英＋斜长石＋钾长石，水云母含量高，角闪石、斜发沸石和滑石含量低；（2）叙长石＋方解石＋石英＋钾长石，角闪石、斜发沸石和滑石含量高，水云母含量低。（1）类矿物组合反映陆源物质较多，火山沉积作用较弱；（2）类组合反映火山沉积物较多，陆源物质较少。矿物组合的变化还具有地层学意义，并可反映古气候的演化。

The mineral compositions in 52 sediment samples of three cores taken in 1988in the West Phillippine Sea were obtained by X-ray diffraction method. The majorminerals were calcite, quartz, plagioclase and potash feldspar, and the subordinateminerals were kaolinite, chlorite, amphibole, clinoptilolite, hydromica, smectite andtale. There were two mineral assemblages in these sediments: (1) calcite+quartz+plagioclase+potash feldspar, coexisted with hydromica of higher content and amphi-bole, clinoptilolite and tale of lowe f contents; (2) plagioclase+calcite+quartz+po-tash feldspar, coexisted with amphibole, clinoptilolite and tale of higher contents andhydromica of lower content. Assemblage (1) reflects that there were more terrige-nous materials and fewer volcanic sediments in the sediments. Assemblage (2) re-flects that there were more volcanic sediments and fewer terrigenous materials inthe sediments. The changes of mineral assemblages have an important role in stra-tigraphic division and have geo1ogical implications in pa1eoclimate evolution.