三叠纪巨型季风在澳大利亚西北大陆架North Carnarvon盆地的沉积记录

Sedimentary Records of Triassic Megamonsoon in North Carnarvon Basin,the Northwest Shelf of Australia

国内外众多学者多年来的研究和实验都显示全球三叠纪泛大陆受到巨型季风的影响。三叠纪澳大利亚西北大陆架North Carnarvon盆地位于特提斯洋南缘,是否受到季风的影响及影响程度如何值得探讨。North Carnarvon盆地三叠系一系列沉积记录表明其受到了明显的巨型季风影响,主要表现在:①三叠纪发育巨厚浅水辫状河三角洲;②薄煤层广泛分布,粗砂岩与富有机质泥岩频繁互层;③发育多期河道、多期冲刷面和水道滞留沉积;④高山植物孢粉与低地植物孢粉混合互层。上述沉积记录对研究同类盆地季风对沉积作用的影响有一定参考价值。

Researches have shown that the Pangaea in Triassic was influenced by the Megamonsoon. This paper discusses if the Megamonsoon influenced the North Carnarvon Basin and how the influence hap- pened. A serial sedimentary evidences revealed that the North Carnarvon Basin was strongly affected by the Triassic Megamonsoon, which was mainly reflected in： （1） Huge thick shallow braided river deltas were developed in the basin~ （2） Thin coal seam widely distributed, sandstone and organic rich mudstone imbedded frequently~ （3） Multistage channel, multistage scour surfaces and channel lag deposit were found in the core; （4） Alpine plant sporopolen and low plant sporopollen mixed and were interbeded. The sedimentary records above have certain directive significance of the influence of monsoon on deposition.