Structure and tectonic history of the foreland basins of southernmost South America
Structure and tectonic history of the foreland basins of southernmost South America
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南美洲最南端前陆盆地的结构和构造历史
DOI：
10.1016/j.jsames.2009.07.006
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发表时间：
2010
影响因子：
1.8
通讯作者：
Y. Zapata
中科院分区：
文献类型：
--
作者：
M. Ghiglione;J. Quinteros;D. Yagupsky;Pedro Bonillo;Julio Hlebszevtich;V. Ramos;G. Vergani;D. Figueroa;S. Quesada;Y. Zapata
描述和分析了邻近的南方（马加拉内斯）、马尔维纳斯和南马尔维纳斯（南福克兰）沉积盆地的共同点和差异。这些盆地的构造历史涉及三叠纪至侏罗纪地壳伸展，随后在弧后的早白垩世热沉降，其次是晚白垩世-古近纪挤压阶段，以及新近纪到现今的褶皱-冲断带失活为主的扳手变形。同时提出了三个盆地晚白垩世前陆阶段的同步启动和晚白垩世-新生代的完整历史。下古新统-下始新统的主要初始前渊沉积中心是基底域的边界，现在变形为薄皮褶皱冲断带。在古新世晚期-始新世早期，由于德雷克海峡最初开放之前南美洲和南极洲之间分离速度加快而导致的临时伸展制度，在南极和马尔维纳斯盆地形成了一些伸展沉积中心。这些伸展沉积中心叠加到以前的远端前渊沉积中心，滞后于前渊阶段的开始和挤压变形的开始。另一套普遍的正断层的古新世到最近的年龄，可以认识到整个盆地被解释为岩石圈的弯曲弯曲的后果，在南马尔维纳斯群岛盆地的协议与以前的研究。在渐新世，由于构造板块重组，挤压变形被逆冲运动所取代。目前，南马尔维纳斯盆地主要是其活动边缘的逆冲隆起，沉积物供应较少，而向西盆地则经历了拉分沉积中心和先前构造的逆冲隆起的局部发展。每个盆地的不同部分的岩石圈的有效弹性厚度计算使用动态有限元数值模型，模拟岩石圈的响应，以推进构造负荷与积极的沉积。
The common elements and differences of the neighboring Austral (Magallanes), Malvinas and South Malvinas (South Falkland) sedimentary basins are described and analyzed. The tectonic history of these basins involves Triassic to Jurassic crustal stretching, an ensuing Early Cretaceous thermal subsidence in the retroarc, followed by a Late Cretaceous–Paleogene compressional phase, and a Neogene to present-day deactivation of the fold–thrust belt dominated by wrench deformation. A concomitant Late Cretaceous onset of the foreland phase in the three basins and an integrated history during the Late Cretaceous–Cenozoic are proposed. The main lower Paleocene–lower Eocene initial foredeep depocenters were bounding the basement domain and are now deformed into the thin-skinned fold–thrust belts. A few extensional depocenters developed in the Austral and Malvinas basins during late Paleocene–early Eocene times due to a temporary extensional regime resulting from an acceleration in the separation rate between South America and Antarctica preceding the initial opening of the Drake Passage. These extensional depocenters were superimposed to the previous distal foredeep depocenter, postdating the initiation of the foredeep phase and the onset of compressional deformation. Another pervasive set of normal faults of Paleocene to Recent age that can be recognized throughout the basins are interpreted to be a consequence of flexural bending of the lithosphere, in agreement with a previous study from South Malvinas basin. Contractional deformation was replaced by transpressive kinematics during the Oligocene due to a major tectonic plate reorganization. Presently, while the South Malvinas basin is dominated by the transpressive uplift of its active margin with minor sediment supply, the westward basins undergo localized development of pull-apart depocenters and transpressional uplift of previous structures. The effective elastic thickness of the lithosphere for different sections of each basin is calculated using a dynamic finite element numerical model that simulates the lithospheric response to advancing tectonic load with active sedimentation.