沉积学报2025，Vol.43Issue(2)：408-422,15.DOI:10.14027/j.issn.1000-0550.2023.040
柴北缘西段早石炭世构造—沉积格局
Early Carboniferous Tectono-sedimentary Pattern in the Western North Margin of Qaidam Basin:Evidence from the rare earth elements of the Lower Carboniferous Huaitoutala Formation
摘要
Abstract
[Objective]The Carboniferous deposits developed in the north margin of Qaidam Basin,which records the history of the transition from Proto-Tethyan to Paleo-Tethyan Ocean.However,the high metamorphism of the Car-boniferous system restricts our understanding of the regional tectono-sedimentary pattern.The rare earth element(REE)properties of argillaceous rocks are stable;therefore,analysing their geochemical characteristics is an effi-cient path for reconstructing the tectonic setting,material source,and sedimentary environment.[Methods]Induc-tively coupled plasma mass spectrometry(ICP-MS)has been applied to investigate REE geochemistry in the Lower Carboniferous Huaitoutala Formation(C1h)in Xiaosaishenteng Shan.[Results]The results indicate that the Xiao-saishenteng Shan area was likely a back-arc basin influenced by the northern subduction of the South Kunlun oceanic crust,located between the local highland composed of the Qaidam block and the subduction collision zone in the northern margin and the western extension zone of the Zongwulong continental rift.Thus,it exhibits an overall pal-aeogeomorphic pattern of"high in the south and low in the north,from land to sea".The orogenic belt extending west from the subduction collision zone in the north margin of Qaidam to the southeast of Xiaosaishenteng Shan was the im-portant provenance area,providing the weathered detrital materials of parent rocks composed of granite,alkaline basalt,and sedimentary rock to the study area since the early deposition of the C1h.With the weakening of regional tectonic intensity,the clastic materials of argillaceous interlayers in the top C1h carbonates may come from the re-transport of the preexisting sediments.Overall,the sedimentary paleo-water of C1h showed a trend of shallow to deep and to shallow again.The clastic shale was formed in a relatively anoxic environment,while the mudstone inter-layers in carbonate rocks occurred in an oxidized environment.The phase sequence of"platform edge shoal-platform front slope-shelf edge-platform front slope-platform edge organic reef"was developed successively.[Conclusions]Our results provide a basis for the reconstruction of the regional paleogeographic pattern and our understanding of the spatiotemporal evolution of the Proto-Tethys oceans and its energy and mineral effects.关键词
构造背景/物源/沉积环境/早石炭世/小赛什腾山Key words
tectonic setting/provenance/depositional environment/Early Carboniferous/Xiaosaishenteng Shan分类
地质学引用本文复制引用
施辉,王波,胡俊杰,吴志雄,马立成..柴北缘西段早石炭世构造—沉积格局[J].沉积学报,2025,43(2):408-422,15.基金项目
中国地质调查局地质调查项目(DD20230260,DD20230313)[The Geological Survey Projects of China Geological Survey,No.DD20230260,DD20230313] （DD20230260,DD20230313）
