Transantarctic Basin: new insights from fission track and structural data from the USARP Mountains and adjacent areas (Northern Victoria Land, Antarctica)
Transantarctic Basin: new insights from fission track and structural data from the USARP Mountains and adjacent areas (Northern Victoria Land, Antarctica)
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横贯南极盆地：来自 USARP 山脉及邻近地区（南极洲北维多利亚地）的裂变径迹和结构数据的新见解
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
T. Schäfer
中科院分区：
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作者：
F. Lisker;A. Läufer;M. Olesch;F. Rossetti;T. Schäfer
USARP山脉包括两个南北走向的山脉（丹尼尔斯山脉，波梅兰茨高原），位于沿着北方维多利亚地（NVL）的伦尼克冰川西缘。来自波默兰茨台地花岗岩样品的四个锆石和钛铁矿裂变径迹（FT）年龄在369-392 Ma的共同范围内。 从USARP山脉采集的20个花岗岩港湾侵入岩样品的磷灰石FT年龄明显较年轻（86-270 Ma）;它们的平均径迹长度（MTL）在11.0 - 13.9 μm之间变化。 六个样品来自Renirie岩石和Kavrayskiy山东部的USARP山脉有更年轻的，一致的磷灰石FT年龄为43-71 Ma，MTL为12.2-14.0 μm。 热年代学数据的热历史模型表明，丹尼尔斯山脉和波梅兰茨高原都经历了一个共同的中生代地质历史，包括中泥盆世的快速剥蚀脉冲，随后是石炭纪和侏罗纪之间的长期剥蚀阶段。后一时期的剥蚀与东部的泛寒武盆地的形成是同时发生的。因此，我们认为USARP山脉是灯塔超群的主要源区之一，形成了横贯南极盆地的填充。在Beacon序列沉积之后，USARP山脉现已露头的岩石被埋藏的最大深度为4.2 km。 在最大埋藏时间推断古地理梯度为25±8°C km−1。由于冈瓦纳大陆的解体，并响应新生代裂谷和隆升的跨南极盆地的反转，触发了自白垩纪以来NVL记录的最后剥蚀阶段。因此，剥蚀量向东增加。而2.4-4.2公里的地壳卸载被认为是自白垩纪以来的USARP山脉，超过4公里的剥蚀发生在伦尼克地堑自始新世以来。 这种剥蚀与主要的断层活动有关，涉及早期ENE-WSW向E-W向延伸。在新生代，相关构造被主导的NW-SE至NNW-SSE方向的右侧剪切重新激活，该剪切与伦尼克地堑构造凹陷的形成和反转有遗传联系。
The USARP Mountains comprise two N–S‐aligned mountain ranges (Daniels Range, Pomerantz Tableland) located along the western margin of the Rennick Glacier in Northern Victoria Land (NVL). Four zircon and titanite fission track (FT) ages from granitic samples from the Pomerantz Tableland fall in a common range of 369–392 Ma. The apatite FT ages from 20 Granite Harbour Intrusive rocks sampled throughout the USARP Mountains are distinctively younger (86–270 Ma); their mean track lengths (MTL) vary between 11.0 and 13.9 μm. Six samples from Renirie Rocks and the Kavrayskiy Hills east of the USARP Mountains have even younger, concordant apatite FT ages of 43–71 Ma, and MTL of 12.2–14.0 μm. Thermal history modelling of the thermochronological data indicate that both the Daniels Range and Pomerantz Tableland experienced a common Phanerozoic geologic history consisting of a mid‐Devonian pulse of rapid denudation, followed by a protracted denudation stage between the Carboniferous and Jurassic. This latter period of denudation was contemporaneous with the formation of the Transantarctic Basin to the east. We consequently suggest that the USARP Mountains were one of the major source areas for the Beacon Supergroup that formed the fill of the Transantarctic Basin. Subsequent to the deposition of the Beacon sequence, the now‐outcropping rocks of the USARP Mountains were buried to a maximum depth of 4.2 km. A palaeogeothermal gradient of 25±8°C km−1 was inferred at the time of maximum burial. Inversion of the Transantarctic Basin due to the breakup of Gondwana, and in response to Cenozoic rifting and uplift of the Transantarctic Mountains, has triggered the final denudation stages recorded in NVL since the Cretaceous. Thereby, the amounts of denudation increase eastward. Whereas 2.4–4.2 km of crustal unloading are recognized for the USARP Mountains since the Cretaceous, more than 4 km of denudation has occurred towards the Rennick Graben alone since the Eocene. This denudation was associated with major fault activities involving early ENE–WSW to E–W‐directed extension. Related structures were reactivated by dominant NW–SE to NNW–SSE‐oriented right‐lateral shear genetically linked to the formation and inversion of the structural depression of the Rennick Graben in Cenozoic times.