古地理学报2024，Vol.26Issue(2)：255-268,14.DOI:10.7605/gdlxb.2024.02.019
上奥陶统五峰组海底麻坑沉积的首次识别及其地质意义
First identification and its geological significance of seafloor pockmarks sediments in the Upper Ordovician Wufeng Formation in China
摘要
Abstract
Seafloor pockmarks are commonly seen in various marine environments.The study on the pockmark sediments,however,have been hardly involved in the literature,causing few knowledges of their characteristics,origin and identification.In this study,we recognized the pockmark sediments from the Paleozoic fine-grained rocks for the first time in China.Based on the field observations and sampling of Upper Ordovician Wufeng Formation at Ganziping and Xiebutou in Shizhu,Chongqing,we tested pock-mark rocks with microscope,scanning electron microscope(SEM),and major and trace element analy-ses.We found the bed chaos and arched beds in the lentoid or cuneal pockmark sediment body.Breccia carved by siliceous veins,are commonly seen,together with asphalt and barite,hematite minerals in the pockmark sediments.Observations and results of major element and REE suggest that the formation of pockmarks were unrelated with hydrothermal liquid and cold seeps.All the geological facts indicate the low-matured oil and gas generated from the Wufeng Formation as the first essential for the formation of pockmarks.The identification marks of deep-time pockmarks are thought as:(i)negative relief in seismic sections,(ii)lentoid or cuneal sediment body,(iii)chaos beds,(iv)arched beds,and(v)hiatus and temporal chaos of sediments.Meanwhile,petrological,stratigraphical,paleoenvironmental and petro-geological significances of the pockmarks in the Wufeng Formation are discussed in this study.关键词
海底麻坑/细粒岩/五峰组/奥陶系/四川盆地Key words
seafloor pockmarks/fine-grained rocks/Wufeng Formation/Ordovician/Sichuan Basin分类
天文与地球科学引用本文复制引用
时志强,彭深远,赵子腾..上奥陶统五峰组海底麻坑沉积的首次识别及其地质意义[J].古地理学报,2024,26(2):255-268,14.基金项目
四川省科技计划项目(编号:2021YJ0353)和国家自然科学基金(编号:41272131)联合资助.[Co-funded by Science and Tectnology Planning Project,Sichuan Province(No.2021YJ0353)and National Natural Science Foundation of China(No.41272131)] （编号:2021YJ0353）
