L. Clemmensen, Dennis Kent, M. Mau, O. Mateus, J. Milán
{"title":"Triassic lithostratigraphy of the Jameson Land Basin (central East\u0000Greenland), with emphasis on the new Fleming Fjord Group","authors":"L. Clemmensen, Dennis Kent, M. Mau, O. Mateus, J. Milán","doi":"10.37570/bgsd-2020-68-05","DOIUrl":"https://doi.org/10.37570/bgsd-2020-68-05","url":null,"abstract":"The lithostratigraphy of the Triassic deposits of the Jameson Land Basin in\u0000central East Greenland is revised. The new Scoresby Land Supergroup is now\u0000composed of the Wordie Creek, Pingo Dal, Gipsdalen and Fleming Fjord Groups.\u0000This paper only deals with the lithostratigraphy of the late Early-Late Triassic\u0000continental deposits of the latter three groups with emphasis on the vertebratebearing\u0000Fleming Fjord Group. The new Pingo Dal Group consists of three new\u0000formations, the Rødstaken, Paradigmabjerg and Klitdal Formations (all elevated\u0000from members), the new Gipsdalen Group consists of three new formations,\u0000the Kolledalen, Solfaldsdal (with the new Gråklint Member) and Kap Seaforth\u0000Formations (all elevated from members), and the new Fleming Fjord Group is\u0000subdivided into three new formations, the Edderfugledal, Malmros Klint and\u0000Ørsted Dal Formations (all elevated from members). The Edderfugledal Formation\u0000contains two cyclic bedded, lacustrine members, a lowermost Sporfjeld Member\u0000(elevated from beds), and an uppermost Pingel Dal Member (elevated from beds).\u0000The lacustrine red beds of the Malmros Klint Formation are not subdivided. The\u0000lacustrine and fluvial Ørsted Dal Formation contains three new members. In the\u0000eastern and central part of the basin, the formation is initiated by cyclic bedded,\u0000red lacustrine mudstones of the Carlsberg Fjord Member (elevated from beds),\u0000while in the northwestern part of the basin the lowermost part of the formation\u0000is composed of grey fluvial conglomerates and sandstones with subordinate red\u0000mudstones of the Bjergkronerne Member (elevated from beds). The uppermost part\u0000of the formations in most of the basin is composed of cyclic bedded, variegated\u0000lacustrine mudstones and grey to yellowish marlstones of the Tait Bjerg Member\u0000(elevated from beds). The sediments in the Fleming Fjord Group contain remains\u0000of a rich and diverse vertebrate fauna including dinosaurs, amphibians, turtles,\u0000aeotosaurs, pterosaurs, phytosaurs and mammaliaforms. Most vertebrate bones\u0000have been found in uppermost Malmros Klint Formation, and in the Carlsberg\u0000Fjord and Tait Bjerg Members. The Norian–early Rhaetian, lacustrine Fleming\u0000Fjord Group was deposited at about 41° N on the northern part of the supercontinent\u0000Pangaea. Lacustrine sedimentation was controlled by seasonal as well as\u0000longer-term (orbital) variation in precipitation. Precipitation was probably brought\u0000to the basin by southwesterly winds. The lacustrine sediments of the uppermost\u0000Fleming Fjord Group show deposition during increasingly humid conditions\u0000changing the lake environment from an ephemeral lake-steppe area to a perennial\u0000lake. This evolution of lake environment suggests a change from a winter-wet\u0000temperate climate to one with precipitation throughout the year.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41469957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}