Origin of the Adventure Subglacial Trench linked to Cenozoic extension in the East Antarctic Craton
Origin of the Adventure Subglacial Trench linked to Cenozoic extension in the East Antarctic Craton
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探险冰下海沟的起源与东南极克拉通新生代扩张有关
DOI：
10.1016/j.tecto.2015.12.011
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发表时间：
2016
期刊：
影响因子：
2.9
通讯作者：
F. Salvini
中科院分区：
文献类型：
--
作者：
P. Cianfarra;F. Salvini
南极板块占据着独特的地球动力学环境，大部分被发散或转换边缘所包围。主要的陆内盆地和高地是其基岩的特征，埋藏在34 Ma的东南极冰盖(EAIS)下。它们在东南极内部克拉通岩石圈顶部的形成仍然是一个重大的悬而未决的问题。提出了后中生代板内伸展构造活动对它们的发育作用，并得到了这项工作的支持。在这里，我们集中于探险冰下海沟(AST)，它的起源缺乏限制和争议，因为现有的地球物理模型表明，要么是伸展构造起源，要么是挤压构造起源。AST是一个长250多公里、宽60公里的冰下海槽，沿NNW-SSE方向延伸，毗邻威尔克斯冰下盆地的最西侧，与区域尺度的磁异常和重力异常排列平行。地球物理运动使AST地形图有了更好的清晰度，显示了其典型的半地块几何形状。通过构造数值模拟，模拟了天桥西翼的圆形形态。我们认为，由于EAIS的侵蚀/沉积能力可以忽略不计，冰下景观主要反映了新生代影响东南极内部的构造过程的保存遗迹。基岩形态通过Listric冒险断层的活动复制，其特征是在地壳底部发生底部拆离(34公里)，垂直位移为2.5公里。这一长度表明了它的区域/地壳重要性。预测的位移要么被解释为新形成的断层，要么被解释为沿着主要的前寒武纪地壳尺度构造边界的较弱地带的部分重新激活。AST的伸展体制是一条更广泛的800公里长的板内走廊的一部分，其特点是新生代几乎沿走向伸展，具有左侧扭压成分。这条走廊可能代表了板块运动引起的远场应力的影响。
The Antarctic plate occupies a unique geodynamic setting being mostly surrounded by divergent or transform margins. Major intracontinental basins and highlands characterize its bedrock, buried under the 34 Ma East Antarctic Ice Sheet (EAIS). Their formation atop of the cratonic lithosphere in the interior of East Antarctica remains a major open question. Post-Mesozoic intraplate extensional tectonic activity has been proposed for their development and is supported by this work. Here we focus on the Adventure Subglacial Trench (AST) whose origin is poorly constrained and controversial, as currently available geophysical models suggest either extensional or compressional tectonic origin. The AST is an over 250-km-long, 60-km-wide subglacial trough, elongated in the NNW–SSE direction adjacent to the westernmost flank of the Wilkes Subglacial Basin, and is parallel to regional scale alignments of magnetic and gravimetric anomalies. Geophysical campaigns allowed better definition of the AST physiography showing its typical half-graben geometry. The rounded morphology of the western flank of the AST was simulated through tectonic numerical modelling. We consider the subglacial landscape to primarily reflect a preserved relict of the tectonic processes affecting the interior of East Antarctica in the Cenozoic, due to the negligible erosion/deposition capability of the EAIS. The bedrock morphology was replicated through the activity of the listric Adventure Fault, characterized by a basal detachment at the base of the crust (34 km) and a vertical displacement of 2.5 km. This length suggests its regional/crustal importance. The predicted displacement is interpreted either as a newly formed fault or as the partial reactivation of a weaker zone along a major Precambrian crustal-scale tectonic boundary. The extensional regime in the AST is part of a more extensive 800-km long intraplate corridor characterized by nearly along-strike extension in Cenozoic times with a left-lateral transpressional component. This corridor may represent the effect of far-field stresses induced by plate motions.
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影响因子：
1.6
作者：
Andrew Wright;M. Siegert
通讯作者：
Andrew Wright;M. Siegert
DOI：
10.5194/esurf-3-139-2015
发表时间：
2014-07
期刊：
--
影响因子：
--
作者：
K. Rose;N. Ross;T. Jordan;R. Bingham;H. Corr;F. Ferraccioli;A. L. Brocq;D. Rippin;M. Siegert
通讯作者：
K. Rose;N. Ross;T. Jordan;R. Bingham;H. Corr;F. Ferraccioli;A. L. Brocq;D. Rippin;M. Siegert
影响因子：
5.2
作者：
Aitken, A. R. A.;Young, D. A.;Siegert, M. J.
通讯作者：
Siegert, M. J.
影响因子：
5.3
作者：
Jamieson, Stewart S. R.;Sugden, David E.;Hulton, Nicholas R. J.
通讯作者：
Hulton, Nicholas R. J.