The Permo-Triassic Gondwana sequence, central Transantarctic Mountains, Antarctica: Zircon geochronology, provenance, and basin evolution
The Permo-Triassic Gondwana sequence, central Transantarctic Mountains, Antarctica: Zircon geochronology, provenance, and basin evolution
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DOI：
10.1130/ges01345.1
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发表时间：
2017-02-01
期刊：
影响因子：
2.5
通讯作者：
Hulett, Samuel R. W.
中科院分区：
文献类型：
--
作者：
Elliot, David H.;Fanning, C. Mark;Hulett, Samuel R. W.
南极洲最完整的二叠纪-三叠纪冈瓦纳纪地层序列出露于横贯南极山脉的中部。下二叠统地层沉积于克拉通内盆地，晚二叠世演化为前陆盆地。沉积岩石学和古水流数据已被解释为指示花岗岩（克拉通）的源区和西南极火山源区。为了解决西南极洲的物源和碎屑输入的演变，碎屑锆石颗粒从9个砂岩（加上3个砂岩先前报道），代表了整个范围的二叠纪-三叠纪序列暴露在该侧翼的盆地，已被分析敏感的高分辨率离子微探针。结果定义了三个来源：早日（早-中二叠世）以罗斯造山带年龄的锆石为主的物源（600-480 Ma）;（晚二叠世）物源以二叠纪锆石为主，其次为较老的岩浆弧颗粒和较小的罗斯造山时代颗粒;和后期（三叠纪）物源，这是相当可变的，其中主要的三叠纪弧成分范围从非常小到显着，并再次与罗斯造山颗粒的组成部分。碎屑锆石意味着冈瓦纳大陆边缘在时间和空间上存在比露头数据明显的更广泛的二叠-三叠纪弧。锆石数据集成到一个模型的盆地演化和填充，提供了广泛的约束时间的构造事件和物源。
The most complete Permian-Triassic Gondwana succession in Antarctica crops out in the central Trans-ant-arc-tic Mountains. The lower Permian strata were deposited in an intracratonic basin that evolved into a foreland basin in late Permian time. Sedimentary petrology and paleocurrent data have been interpreted as indicating a granitic (craton) provenance and a West Antarctic volcanic provenance. To address the West Antarctic provenance and evolution of the detrital input, detrital-zircon grains from nine sandstones (plus three sandstones reported previously) representing the full extent of the Permo-Triassic succession exposed on that flank of the basin, have been analyzed by sensitive high-resolution ion microprobe. Results define three provenances: an early (early to middle Permian) provenance that is dominated by zircons having Ross orogen ages (600-480 Ma); a middle (late Permian) provenance dominated by Permian zircons with subordinate older magmatic arc grains plus lesser Ross orogen-age grains; and a late (Triassic) provenance, which is quite variable and in which the predominant Triassic arc component ranges from very minor to significant and again with a component of Ross orogenage grains. Detrital zircons imply a more extensive Permo-Triassic arc, in time and space, on the Gondwana margin than is evident from outcrop data. The zircon data are integrated into a model for basin evolution and infilling, providing broad constraints on the timing of tectonic events and the provenance.