成都理工大学学报（自然科学版）2026，Vol.53Issue(3)：494-511,18.DOI:10.12474/cdlgzrkx.2024112101
四川盆地宝塔组古水深重建——沉积相与微生物组构证据
Palaeobathymetric reconstruction of the Pagoda Formation in the Sichuan Basin:evidence from sedimentary facies and microbial fabrics
摘要
Abstract
The deposition of the Upper Ordovician Pagoda Formation in the Sichuan Basin(South China)corresponds to a critical period of transition from the Great Ordovician Biodiversification Event to the Late Ordovician mass extinction.The study of the paleo-water depth and evolution during the deposition of the Pagoda Formation provides significant insights into the sedimentary environmental evolution of the Sichuan Basin and global environmental changes during this period.However,it remains a subject of debate.We conducted sedimentological and microbial fabric analyses of limestones from the Pagoda Formation at sections including Haima(Xingwen,Sichuan),Qiaoting(Nanjiang,Sichuan),and Anwen(Qijiang,Chongqing)to reconstruct the paleo-water depth.The sedimentary facies of the Pagoda Formation and its underlying strata can be subdivided ascendingly into evaporative restricted platform facies,mixed open platform margin shoal facies,mixed restricted platform facies,and carbonate ramp facies,which have collectively recorded a transgressive process from shallow-water to deep-water environments during the depositional period.In the basal limestone of the Pagoda Formation,the identification of calcified cyanobacterial communities,including Girvanella,Subtifloria,and Proaulopora,along with their assemblages,indicate deposition within the shallow-water environment of the upper photic zone(～50 m water depth).In the middle-to-upper limestone intervals of the Pagoda Formation,these calcified cyanobacteria disappeared,while microbial boring fabrics associated with green algae(reticulate borings)and fungi(filamentous and spherical borings)are recognized.This shift suggests a significant increase in water depth to the low-light zone below the photic zone(>100 m),further supporting a rapid transgression-induced water deepening process on the Yangtze Platform during the Late Sandbian to Early Katian stages.These findings provide critical insights into the mechanisms driving global climate fluctuations and biodiversity changes during the Late Ordovician,highlighting their indicative significance for understanding the origins of these paleoenvironmental and biotic events.关键词
宝塔组/碳酸盐岩微相/钙化蓝细菌/钻孔微生物Key words
Pagoda Formation/carbonate microfacies/calcified cyanobacteria/endolithic micro-organisms分类
天文与地球科学引用本文复制引用
耿婉婷,曾敏,黄祥锐,陈思,靳晓雨..四川盆地宝塔组古水深重建——沉积相与微生物组构证据[J].成都理工大学学报（自然科学版）,2026,53(3):494-511,18.基金项目
国家自然科学基金(41102065,41872110) （41102065,41872110）
云南大学双一流建设项目(CZ21623201,C1762101030017). （CZ21623201,C1762101030017）
