重庆科技大学学报（自然科学版）2025，Vol.27Issue(3)：1-11,11.DOI:10.19406/j.issn.2097-4531.2025.03.001
渝东北巫山地区二叠系孤峰组黑色岩系的地球化学约束及其意义
Geochemical Constraints and Its Significance on the Black Rock Series of Gufeng Formation in the Middle Permian,Wushan Area,Northeastern Chongqing
摘要
Abstract
This study investigates the depositional environment,material sources,and genesis of siliceous rocks in the Permian Gufeng Formation black rock series through elemental geochemical analysis of the Yangliuping section in Wushan,northeastern Chongqing.Fourteen groups of black rock samples from the Gufeng Formation were col-lected,and their macro elements,trace elements,and rare earth elements(REE)were tested using ICP-OES and ICP-MS techniques.The analysis of macro elements reveals that the λ(Al/(Al+Fe+Mn))ratios of carbonaceous si-liceous rocks,siliceous rocks,and carbonaceous mudstones in the study area are 0.36～0.55,0.55～0.62,and 0.62～0.66,respectively.Also,the λ(Si/(Si+Al+Fe))ratios of carbonaceous siliceous rocks and siliceous rocks is 0.90～1.00,and the λ(Al2O3/(Al2O3+Fe2O3))ratios of carbonaceous siliceous rocks、siliceous rocks and car-bonaceous mudstones are 0.43～0.62,0.62～0.69,and 0.69～0.72,respectively.This indicators that the sili-ceous rocks of the Gufeng Formation are biogenic and formed in a continental margin environment,while the carbo-naceous siliceous rocks and carbonaceous mudstones are closely related to terrigenous clastic materials.Trace element analysis shows that the λ(B/Ga)ratios in carbonaceous mudstones is 4.55～4.82,and the λ(Sr/Ba)ratios is 1.60～2.10.The λ(B/Ga)ratios in carbonaceous siliceous rocks and siliceous rocks is 7.12～20.00.Combined with the λ(V/(V+Ni))ratios,suggesting that the rocks primarily formed in a marine anoxic environment.From the bottom to the top of the profile,the δCe values of siliceous rocks gradually decrease,and the significant positive correlation between Al2O3 and REE suggests that the sedimentary water gradually deepened but remained influenced by terrigenous materials.Integrated geochemical evidence demonstrates that the black carbonaceous siliceous rocks,carbonaceous mudstones,and siliceous rocks of the Gufeng Formation primarily formed in anoxic,deep-water shelf environments along continental margins.关键词
巫山地区/二叠系/孤峰组/黑色岩系/地球化学Key words
Wushan Area/permian/Gufeng formation/black rock series/geochemistry分类
天文与地球科学引用本文复制引用
陈迪舒,张烨,彭俊菲..渝东北巫山地区二叠系孤峰组黑色岩系的地球化学约束及其意义[J].重庆科技大学学报（自然科学版）,2025,27(3):1-11,11.基金项目
国家自然科学青年基金项目"雅鲁藏布江缝合带三叠纪放射虫及其对新特提斯洋早期演化的约束"(42302027) （42302027）
