黄河、长江和珠江三角洲近代沉积物的沉积化学特征

黄河、长江和珠江是我国直接入海的三条最大河流，流域面积之和占我国直接入海主要河流流域面积的90%。三大河三角洲近代沉积物的沉积化学特点是：黄河三角洲CaO含量高，而A12O3、TiO2和有机质含量均较低；长江三角洲的MgO、MnO含量略高；珠江三角洲的Fe2O3、TiO3含量高，CaO含量低。这种沉积化学特征的差别，是由于沉积化学成分受地带性的生物气候及河口地球化学环境制约的结果。

Sedimentary chemical characteristics of recent sediments in Huanghe,Changjiang and Zhujiang Rivers Deltas

Study results of sedimentary chemical characteristics of recent sediments in the Huanghe(Yellow),Changjiang (Yangtze) and Zhujiang (Pearl) Rivers Deltas show bigger differencesin sedimentary chemical characteristics of recent sediments in the three rivers deltas.The CaO content is high and the Al2O3,TiO2 and organic matter contents are lower inHuanghe River Delta; the concentrations of MnO, MgO in the Changjiang River Delta arehigher than those from the Huanghe and Zhujiang Deltas; the Fe2O3, TiO2 contents are highand the Cao content is lower ln the Zhujiang River Delta. The differences in sedmentarychemical characteristics result from sedmentary chemical compositions contolling the zonalbiogenic climate and the estuarine geochemical environments.