- 作者: 陳汝勤
- 作者服務機構: Institute of Oceanography National Taiwan University
- 中文摘要: The mineralogy and geochemistry of shelf sediments from the South China Seaand Taiwan Strait have been studied to gain some knowledge of their provenanceand depositional environments. Two distinct types of neritic sediments wererecognized based on mineralogical and chemical data; they are: (1) the near-shoresediments in Taiwan Strait, and (2) the continental shelf sediments of the SouthChina Sea. The former are characterized by a relatively higher percentage ofterrigenous sediments, higher quartz/K-feldspar ratio, lower CaO and Sr and highercontents of MgO, total Fe as Fe2O3, K2O, Rb and Li as compared with the latter.The mineralogical data suggest that the near-shore sediments in Taiwan Strait arederived mainly from Taiwan Island while the shelf sediments in the South ChinaSea are derived mainly from southern China where granites of Mesozoic age, richin potash feldspar, are widely distributed. The decrease of quartz/calcite ratio inrelation to distance off the China coast strongly indicates that the depositionalenvironment becomes more biogenic towards the edge of the shelf. The effects ofenvironment and provenance are the most important factors controlling the miner-alogical and chemical variations of the sediments studied.
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