The Influence of Inherited Structures on Dike Emplacement during Gondwana Breakup in Southwestern Africa
The Influence of Inherited Structures on Dike Emplacement during Gondwana Breakup in Southwestern Africa
复制标题
西南非洲冈瓦纳古陆解体过程中继承结构对堤坝就位的影响
DOI：
10.1086/671398
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Frimmel
中科院分区：
文献类型：
--
作者：
Frimmel
对南部非洲西海岸从开普敦地区延伸到纳米比亚的白垩纪和前白垩纪构造进行了运动学分析，目的是调查遗传性构造不连续性是否控制了冈瓦纳大陆的分裂和白垩纪南大西洋的相关开放。从安哥拉西南部到非洲南端出露的白垩纪基性岩脉的地图和卫星图像分析增强了这一点。综合结果提供了一致的证据，在白垩纪E-W-NE-SW方向的伸展。从安哥拉南部到纳米比亚-南非边界以东西向伸展为主，从纳米比亚中西部到南非西南海岸则以东北-西南向伸展为主。这两个延伸方向从纳米比亚中西部到纳米比亚最南端重叠。泛非构造的运动学分析提供了南非西南部Saldania带西部ENE-WSW方向缩短和南非与纳米比亚边界附近Gariep带ENE-WSW至ESE-WNW方向收缩的证据。因此，泛非缩短的方向，导致晚新元古代/早寒武世西南冈瓦纳的融合是平行的主要伸展方向在早白垩世冈瓦纳解体和南大西洋裂谷在非洲西南部的启动。这意味着现代南大西洋的开放是由泛非（或更古老）的结构不连续性控制的，这些结构不连续性在早白垩世被重新利用。继承的构造基底各向异性，这是一般平行于主要的线性构造和/或地壳规模的剪切带，显然控制在早白垩世的岩墙侵位和当时的裂谷位置。
A kinematic analysis of Cretaceous and pre-Cretaceous structures was carried out along the west coast of southern Africa extending from the Cape Town area into Namibia with the aim of investigating whether inherited structural discontinuities controlled Gondwana breakup and the associated opening of the South Atlantic in the Cretaceous. This was augmented by map and satellite image analyses of mainly Cretaceous mafic dikes exposed from SW Angola to the southern tip of Africa. The combined results provide consistent evidence of E-W- to NE-SW-directed extension during the Cretaceous. E-W extension dominated from southern Angola to the Namibian–South African border, and NE-SW-directed extension occurred in an area extending from west-central Namibia to the southwestern coast of South Africa. These two extension directions overlap from west-central Namibia to southernmost Namibia. The kinematic analysis of Pan-African structures provides evidence of ENE-WSW-directed shortening in the western Saldania Belt in SW South Africa and ENE-WSW- to ESE-WNW-oriented constriction in the Gariep Belt near the border between South Africa and Namibia. Thus, the Pan-African shortening directions that led to the Late Neoproterozoic/Early Cambrian amalgamation of SW Gondwana are parallel to the main extension directions during Early Cretaceous Gondwana breakup and the initiation of South Atlantic rifting in southwestern Africa. This implies that opening of the modern South Atlantic was controlled by Pan-African (or older) structural discontinuities that were reutilized during the Early Cretaceous. The inherited structural basement anisotropies, which are generally parallel to major lineaments and/or crustal-scale shear zones, apparently controlled dike emplacement in the Early Cretaceous and the location of rifting at that time.
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影响因子：
1.8
作者：
M. Basei;H. Frimmel;A. Nutman;F. Preciozzi
通讯作者：
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影响因子：
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DOI：
--
发表时间：
2011
期刊：
影响因子：
--
作者：
S. Ulrich;J. Konopásek;P. Jeřábek;L. Tajčmanová
通讯作者：
L. Tajčmanová
影响因子：
3.5
作者：
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DOI：
10.1016/s0166-2635(09)01617-x
发表时间：
2009
期刊：
Developments in Precambrian Geology
影响因子：
--
作者：
R. Miller;H. Frimmel;T. Will
通讯作者：
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