下扬子鄂东南南华系莲沱组—南沱组岩性特征及岩相古地理  

Lithological Characteristics and Lithofacies Palaeogeography of the Liantuo-Nantuo Formation of the South China System in the Southeastern Part of Hubei Province

作　　者：许露露 龚志愚 徐聪 赵雪松 翁茂芝 罗红 Xu Lulu;Gong Zhiyu;Xu Cong;Zhao Xiongsong;Weng Maozhi;Luo Hong(Hubei Geological Survey,Wuhan,Hubei 430034)

机构地区：[1]湖北省地质调查院

出　　处：《资源环境与工程》2019年第2期159-163,201,共6页Resources Environment & Engineering

基　　金：湖北1∶5万杨芳林、宝石河、沙洲店幅区域地质矿产综合调查(项目编号:DD20160031-05)

摘　　要：对下扬子鄂东南南华系地层进行剖面测量,描述南华系地层岩性、砾石发育特征及其与顶底地层的接触关系,通过地层对比分析南华系地层沉积相及物源方向。研究表明莲沱组与下伏大药姑组呈角度不整合接触,底部砾石砾径3~15mm,向上砾径逐渐减小,区内常缺失古城组和大塘坡组,南沱组砾石砾径2~15mm,上部砾石比下部略增多,与上覆陡山沱组呈平行不整合接触。莲沱期四斗朱水库剖面离剥蚀区较近,物源丰富,斜层理发育,为河流-三角洲平原沉积环境,郭源村剖面离物源较远,粒度相对较细,岩石呈灰-灰绿色,为三角洲前缘-临滨相沉积环境。南陀组砾石特征表明区内南华系地层物源来自西北方向。The field profile survey of the underlying and overying strata in Guoyuan Village,Tongshan County,southeastern Hubei Province,is carried out.The lithology and gravel development characteristics of the strata and their contact with strata are described in detail. The sedimentary facies and provenance direction of the Nanhua System in the study area are systematically analyzed by stratigraphic correlation.The study shows that the conglomerate of the Liantuo Formation of the South China System exists unconformity contact with the underlying Dayaogu Formation. The bottom gravel diameter is 3~15 mm,and the upward gravel diameter gradually decreases. The deposits are discontinuous in the area,and the Gucheng Formation and the Datangpo Formation are often absent in the middle of the area. The diameter of gravel in Nantuo Formation is 2~15 mm. The upper gravel is slightly larger than the lower gravel. The fine gravel sandstone with moraine at the top is in parallel unconformity contact with the carbonaceous shale of Doushantuo Formation.Stratigraphic correlation shows that during the Liantuo Formation sedimentary period,the Sidouzhu Reservoir profile was close to the denudation area,with abundant provenances,large depositional thickness and well developed oblique bedding. It was a river-delta plain sedimentary environment,while the Guoyuan Village profile was far away from provenance. Therefore,the sediment thickness was smaller,the grain size became finer,and the rocks were grey-greyish-green,belonging to the delta front-coastal sedimentary environment.Gravel characteristics of Nantuo Formation confirm that the source of strata of Nanhua System in the study area is from the Northwest direction.

关 键 词：岩相古地理 岩性特征 莲沱组 鄂东南 

分 类 号：P531[天文地球—古生物学与地层学]