珠江口盆地构造演化及对沉积环境的控制作用

Tectonic Evolution and Its Controlling for Sedimentary Environment in Pearl River Mouth Basin

通过对珠江口盆地沉积物地球化学成分分析表明,大洋钻探计划(ODP)1184站所揭示的主要构造沉积地层界线在珠江口盆地中亦同样存在,其元素在32,23.9,16 Ma存在明显的突变,界线十分明显;这些陆源沉积物成分的变化是构造运动造成源区发生改变的直接证据.化学蚀变指数显示珠江口盆地在32,23.9,16 Ma时期存在物理风化增强而化学风化减弱的突变事件,指示了由于构造运动造成母岩短时期内强烈快速的剥蚀作用,从而引起沉积物化学蚀变指数突然降低.根据元素相关性分析显示,ODP1148站沉积物与珠江口盆地沉积物亲缘关系密切,两者具有相同的物源.

Geochemical analysis reveals that sedimentary boundaries in ODP 1148 also exist in the Pearl River Mouth Basin. The geochemical composition of the sediments had obvious changes at 32,23.9 and 16 Ma, respectively, reflecting tectonic turning points. At the same time, the index of chemical index of alteration（CIA） had also great changes,which indicates strong physical weathering in the source rock areas on these turning points led by tectonic activities. The sediments from ODP 1148 have the a closed relationship with those from the Pearl River Mouth Basin by canonical correlations analysis, reflecting both of them have the same provenance.