西藏昌都察雅地区上三叠统阿堵拉组——夺盖拉组河口湾相的发现及意义  

The discovery and significance of the estuarine facies in the Upper Triassic Adula-Duogaila Formation,Chaya region,Qamdo area,Xizang

作　　者：张青松 牟传龙[1,2,3] 王启宇 侯乾[2,3] ZHANG Qingsong;MOU Chuanlong;WANG Qiyu;HOU Qian(Chengdu University of Technology,Chengdu 610051,China;Chengdu Center,China Geological Survey(Southwest Geological Science and Technology Innovation Center),Chengdu 610218,China;Key Laboratory of Sedimentary Basin and Oil and Gas Resources,MNR,Chengdu 610218,China;Shandong University of Science and Technology,Qingdao 266510,China)

机构地区：[1]成都理工大学,四川成都610051 [2]中国地质调查局成都地质调查中心(西南地质科技创新中心),四川成都610218 [3]自然资源部沉积盆地与油气资源重点实验室,四川成都610218 [4]山东科技大学,山东青岛266510

出　　处：《沉积与特提斯地质》2025年第1期90-101,共12页Sedimentary Geology and Tethyan Geology

基　　金：国家自然科学基金地质联合基金重点项目(U2344209);中国地质调查局项目(DD20221661)。

摘　　要：通过对昌都市察雅县岗卡村阿堵拉组—夺盖拉组剖面沉积构造、岩性组合、沉积序列等进行综合研究,结果表明:(1)阿堵拉组—夺盖拉组沉积期为河口湾相沉积,进一步可划分河流亚相及潮坪亚相,河口湾相的识别与前人提出的三角洲相、滨岸相有较大差异。(2)河流亚相可进一步识别出河床次相、河漫滩次相。河床次相以沉积厚层块状砾岩、长石岩屑砂岩为特征,发育板状、槽状交错层理、平行层理等沉积构造;河漫滩次相沉积粉砂岩、泥岩组合,见碳化植物碎片,发育沙纹层理。(3)潮坪亚相可进一步识别出潮下带、潮间带及潮上带次相,潮下带次相沉积泥质粉砂岩、岩屑砂岩等组合,发育沙纹层理;潮间带次相沉积粉砂岩、泥岩组合,发育干涉波痕、波状层理、透镜状层理等沉积构造;潮上带次相沉积泥岩、含碳质泥岩组合,岩层夹有粉砂岩透镜体,发育水平层理、雨痕等沉积构造。The study of sedimentary structures,lithological combinations,and sedimentary sequences of the Adula-Duogaila Formation in Gangka Village,Chaya County,Qamdo City,shows the presence of estuarine facies during the sedimentary period of the Adula-Duogaila Formation.Further analysis subdivides the estuarine facies into fluvial subfacies and tidal flat subfacies.The fluvial subfacies can be further subdivided into riverbed suborder facies and floodplain suborder facies.The riverbed suborder facies is characterized by thick-bedded conglomerate and feldspathic litharenite,while the floodplain suborder facies is distinguished by deposits of siltstone,mudstone,and carbonized plant fragments.Sedimentary structures such as cross-bedding,trough cross-stratification,and parallel bedding can be observed in the fluvial subfacies.The tidal flat subfacies can be further distinguished into subtidal,intertidal,and supratidal suborder facies.The subtidal suborder facies is characterized by mudstone and lithic sandstone,with the development of ripple bedding.The intertidal suborder facies is characterized by deposition of siltstone and mudstone,with interference ripple marks,lenticular bedding,and wave-like bedding as prominent sedimentary structures.The supratidal suborder facies is characterized by mudstone and carbonaceous mudstone,with interbedded lenses of siltstone,and sedimentary structures such as horizontal bedding and rain prints.

关 键 词：昌都地区 上三叠统 河口湾相 沉积次相 

分 类 号：P618.13[天文地球—矿床学]