沉积学报2018，Vol.36Issue(1)：42-56,15.DOI:10.3969/j.issn.1000-0550.2018.007
皖南志留系唐家坞组物源分析:来自碎屑锆石年代学和岩石地球化学的制约
Provenance Analysis for the Clastic Rocks in Tangjiawu Formation, South Anhui: Constraints from Detrital Zircon Ages and Geochemistry Characteristics
摘要
Abstract
Provenance and sedimentary age are still debated about Tangjiawu Formation from the South Anhui.The study focused on the petrography,geochemical features and detrital zircon ages of the sandstones in the Tangjiawu For-mation. The sandstones,which are highly rounded and sorted, are essentially composed of metamorphic detritus and quartz with wave extinction. They exhibited relatively high compositional maturity. Their provenances were dominated by felsic materials that had undergone intensive chemical weathering or sedimentary recycling. LA-ICP-MS zircon U-Pb dating yields a youngest age of 424 Ma,which represents the lower limit of deposition age.In addition to the zircon ages,the Tangjiawu Formation uncomfortably overlain by the Devonian Guanshan Formation,suggesting that it should be deposited in Late Silurian that approached to the termination timing of the early Palaeozoic orogenic event. Seventy-nine detrital zircons with discordance <10% display a broadly age spectrum of 2 912 Ma to 424 Ma. Most of the de-trital zircons have U-Pb age grouped between 731 and 1 031 Ma,with two clusters peaking at 981 and 756 Ma. A few populations with peak ages of 2 476 Ma,517 Ma and 453 Ma are present as well. This suggested that the provenances of the Tangjiawu Formation were mainly derived from the early-to middle-Neoproterozoic igneous rocks,Late Neoprot-erozoic rift sequence and Sinian to Ordovician sediments with subordinate synorogenic magmatic or sedimentary rocks. The early Palaeozoic intra-continental orogeny caused the uplifting of the sediments in the pre-middle-Ordovician ba-sins,which mostly contributed to sources of the deposits in the intra-continental foreland basin. The deposition and e-volution of the foreland basin in the South China were controlled by the early Palaeozoic orogeny, reflecting the cou-pled material recycling between the orogen and the foreland basin.关键词
唐家坞组/物源/碎屑锆石/地球化学/早古生代造山带/皖南Key words
Tangjiawu Formation/provenance/detrital zircon/geochemistry/early Palaeozoic orogenic belt/South Anhui分类
天文与地球科学引用本文复制引用
杨梅,洪天求,徐锦龙,李秀财,罗雷..皖南志留系唐家坞组物源分析:来自碎屑锆石年代学和岩石地球化学的制约[J].沉积学报,2018,36(1):42-56,15.基金项目
安徽公益性地层工作项目(2016-g-1-5)[Anhui Strata Commonweal Project,No.2016-g-1-5] （2016-g-1-5）
