DOI: 10.1016/j.palaeo.2015.08.004
论文题名: An Early Permian, paleopolar, postglacial, river-dominated deltaic succession in the Mackellar-Fairchild formations at Turnabout Ridge, Central Transantarctic Mountains, Antarctica
作者: Flaig P.P. ; Hasiotis S.T. ; Jackson A.M.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2016
卷: 441 起始页码: 241
结束页码: 265
语种: 英语
英文关键词: Delta front
; Epeiric seaway
; Hyperpycnites
; Icehouse-greenhouse
; Subaqueous terminal distributary channels
英文摘要: Turnabout Ridge, a remote outcrop belt in the Beardmore Glacier Region of the Central Transantarctic Mountains, comprises subglacial-glaciomarine deposits of the Pagoda Formation (Fm) overlain by a postglacial deltaic succession of the Mackellar-Fairchild formations (fms). Four depositional environments were identified in the Mackellar-Fairchild fms: 1) prodelta to distal-delta-front deposits that record the initial filling of a newly formed intracratonic basin; 2) an interval dominated by subaqueous terminal distributary channels and levees that signal the advancement of a delta into the region; 3) mouth bars and associated subaqueous terminal distributaries representing the proximal delta front; and 4) an overlying sand-dominated braidplain.A companion ichnologic study identified 30 ichnogenera in the Mackellar Fm that combine to form six ichnocoenoses. Twelve traces are known only from marine settings, 18 are found across marine, brackish, and freshwater systems, and none are known solely from freshwater systems. The ichnology refines paleoenvironmental and paleosalinity interpretations for the Mackellar Fm, and indicates a predominantly brackish water paleoenvironment.Subaqueous terminal distributary channels record the highest energies, suspended sediment concentrations, and sediment loads, and are the conduits that delivered sediment to the delta front and prodelta. Abundant traction deposits (hyperpycnites) displaying only minor wave or tide modification suggest that the delta is best classified as river-flood dominated. The succession exhibits similarities to the Panther Tongue and Ferron Notom deltas of the Cretaceous Western Interior Seaway, USA, and a Late Ordovician proglacial delta from the Murzuq Basin in Libya.The combined ichnologic and sedimentologic evidence suggests that sediment-laden glacial outburst floods produced freshets that recurrently prepped a shallow-marine basin, reducing salinities and allowing for abundant channelization and hyperpycnite deposition along the delta front. Turnabout Ridge likely occupied a proximal and axial position relative to an Antarctic freshwater- and sedimentation-stressed, river-dominated marine deltaic system along the shoreline of an epeiric seaway during the Early Permian. © 2015 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/68630
Appears in Collections: 过去全球变化的重建
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作者单位: Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Department of Geology, University of Kansas, Lawrence, KS, United States
Recommended Citation:
Flaig P.P.,Hasiotis S.T.,Jackson A.M.. An Early Permian, paleopolar, postglacial, river-dominated deltaic succession in the Mackellar-Fairchild formations at Turnabout Ridge, Central Transantarctic Mountains, Antarctica[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2016-01-01,441