鄂尔多斯盆地延长组遗迹化石组合与古环境

Geological Environment of Trace Fossil Assemblage in Yanchang Formation, Ordos Basin

摘要:

通过对野外剖面、钻井岩芯中遗迹化石组合的分析发现，鄂尔多斯盆地晚三叠世延长期发育的湖泊地层中主要有垂直居住迹（Skolithos和Cylindricum）、垂直觅食迹（Scoyenia）、U形管迹（Arenicolites）、潜穴迹（Planolites、Chondrites和Teichichnus）、水平迹（Protopaleodictyon）、逃逸迹（Fugichnia）、游泳迹及根迹.结果表明：遗迹化石的分布和组合与鄂尔多斯盆地晚三叠世湖盆的沉积环境相匹配，这对于利用遗迹化石组合恢复湖盆岩相古地理具有重要的地质意义.

Abstract:

Through the filed profiles and the trace fossil assemblages from well core, we found that the lake stratums of Yanchang Formation in Ordos Basin were mainly developed in eight relics types: vertical dwelling trace (Skolithos and Cylindricum), vertical browsing trace(Scoyenia), Utube trace (Arenicolites), burrow trace (Planolites, Chondrites and Teichichnus), horizontal trace (Protopaleodictyon), escape trace（Fugichnia）, nekton trace and root trace. It is shown that the distribution and assemblage of trace fossils matches the sedimentary environment of the Late Triassic lake basin in Ordos Basin, reflecting the geological value of the restoration of lithofacies palaeogeography by the use of trace fossil assemblages.