南沙群岛区域地质地貌与古海洋

本文论述了南沙群岛海底地形、海底沉积物、区域地质、珊瑚礁地质地貌和区域古海洋。

REGIONAL GEOLOGY, GEOMORPHOLOGY AND PALEOOCEANOGRAPHY OF THE NANSHA ISLANDS

ome characteristics hi the Nansha Islands , such as bottom relief, bottom sediments,regional geology, geology and geomorphology of coral reefs, and regional paleooceanography are discussed in this paper. The tectonics of the Nansha Islands can be divided into Central Basin Fault-Spread Region, Nansha Faulted Platform Region, and Zengmu Graben Zone.And correspondingly the bottom reliefs are the abyssal plain, Nansha sea plateau, upper continental slope, and continental shelf. Since Cenozoic era, the seas of the Nansha Islands have always been tropical seas. The bioherms have been developing since Late OligoceneEpoch, and the lime-sand islands were formed after Middle Holocene in the seas.Paleoclinlate changed synchronously with the whole world over the past 900 000 years , but the temperatures between glacisl epoch and interglacial stage varied little. Oscillatory paleosea-level change, Caused by the paleoclimate change, resulted in the alternation between emergence and submergence of continent shelf and islands, and in the change of surfacewater circulation model.