沉积学报2024，Vol.42Issue(2)：608-618,11.DOI:10.14027/j.issn.1000-0550.2022.082
陕南勉县寒武系仙女洞组生物礁岩相学及古环境分析
Petrographic Features and Paleoenvironmental Significance of the Lower Cambrian Reef in the Xiannüdong Formation,Mian County,Southern Shaanxi
摘要
Abstract
[Objective]A key point in the evolutionary history of reefs is the widespread occurrence of associated archaeocyath-calcimicrobial communities in the Early Cambrian.The developmental environments and conditions for these reef-building communities deserve more attention.[Methods]We present a case study of the Daheba section in Mian county,located in the Hanzhong-Micangshan area along the northwestern margin of the South China Block.In this region,we conducted comprehensive petrographic,sedimentological,and geochemical analysis of sedimentary successions to investigate reef development in turbid environments.[Results]A detailed petrographic study indi-cates that the Daheba reef was formed in a near-shore,high-energy condition.Calcified microfossils,archaeocyaths and archaeocyath-calcimicrobial communities dominated reef construction from the early to late phases of reef growth.Small amounts of terrigenous particles were found within the inner reef framework,increasing from the base to the top.[Conclusions]This indicates that the reef was tolerant of a small input of terrigenous silts and fine sands during growth.These terrigenous materials material may have provided a source of nutrients and facilitated reef growth;how-ever,an excess of siliciclastics would have abraded reef-building organisms and blocked their feeding passages,per-haps even buried the reef architecture completely.This study has clarified the growth process and environment of an Early Cambrian archaeocyathan-calcimicrobial reef in China,and may provide a reference for further study of Early Cambrian reef systems in paleoenvironmental reconstruction,sedimentology and petroleum geology.关键词
古杯—钙质微生物群落/礁灰岩/古环境指标/寒武纪第三期/汉南—米仓山地区Key words
archaeocyath-calcimicrobial reef/reef limestone/paleoenvironmental proxy/Cambrian Age 3/Hannan-Micangshan area分类
天文与地球科学引用本文复制引用
李雅兰,李怡霖,李飞,吕月健,王夏,王曾俊,李红,易楚恒,李杨凡,曾伟..陕南勉县寒武系仙女洞组生物礁岩相学及古环境分析[J].沉积学报,2024,42(2):608-618,11.基金项目
国家自然科学基金项目(42172136,41872119) National Natural Science Foundation of China,No.42172136,41872119 （42172136,41872119）
