塔里木盆地西缘晚古生代遗迹化石及其沉积环境

Trace fossils of late Palaeozoic from the western border areas of Tarim Basin and its palaeosedimentary environment

通过采集于塔里木盆地西缘哈拉奇地区晚古生代地层中遗迹化石的分析鉴定,共识别出遗迹化石8属10种和1个遗迹相.根据遗迹化石的组合特征及其沉积环境,组建了3个遗迹组,并在遗迹化石基础上结合岩性、古地理环境等特征对研究区沉积环境变迁作了讨论,认为研究区晚古生代经历了多期次海水进退循环,泥盆纪-石炭纪总体海水侵进,沉积环境由滨海逐渐演变为开阔台地,砂泥质沉积发育;二叠纪经历了海退-海进-再次海退的过程,沉积环境依次为滨海-台地边缘斜坡-滞留海湾,碳酸盐沉积发育.这些研究对进一步认识研究区古生物面貌,进而恢复古环境、古生态有重要意义.

Based on the analysis and identification of the trace fossils in late Paleozoic strata from the western border areas of Halaqi of Tarim Basin, Xinjiang, a total of 8 ichnogenus, 10 ichnospecies and an ichnofacies had been identified. Based on the composition and distribution characteristics of these trace fossils and the sedimentary environment, three types of ichnocoenosis under different sedimentary environments had been recognized. According to the analyses above of the trace fossils and combined with the lithologic characteristics of the research area and the ancient geography, the changes in the sedimentary environment had been recognized. During the late Paleozoic, the study area had experienced multiphase cycles of transgression and regression. In the Devonian-Carboniferous period, the study area was controlled by transgression. The sedimentary environment＇changed from littoral facies to open platform facies, and developed the sandy and muddy sediments. The Permian period had undergone such a depositional cycle as retrogression-transgression-retrogression. The sedimentary environment was of littoral facies and platform margin slope facies, barrier coas and developed carbonate deposits. These studies are also of great importance to further understanding the features of paleontology, and the restoration of the ancient environment and paleoecology.