Lithospheric tectonic structures developed under high-grade metamorphism in the Southern part of Madagascar
Lithospheric tectonic structures developed under high-grade metamorphism in the Southern part of Madagascar
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马达加斯加南部高级变质作用下发育的岩石圈构造结构
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
R. Rakotondrazafy
中科院分区：
文献类型：
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作者：
J. Martelat;C. Nicollet;J. Lardeaux;G. Vidal;R. Rakotondrazafy
本文描述了马达加斯加岛南部前寒武纪地壳深部的构造变质演化。这个地壳对应于一个广泛的，后期泛非事件（550-580马）在莫桑比克带的形成过程中改造的西太平洋基底。有限的几何形状和相关的变质作用是通过卫星成像，现场制图和P-T估计使用传统的热压法和TWEEQ软件程序与内部一致的热力学数据和统一的一套解决方案模型。高级变质作用期间开发的结构模式显示了由15公里宽的韧性剪切带分隔的具有复杂褶皱几何形状的域并置。在褶皱域内，千米级的干涉图案与强烈倾斜的变质拉伸线理相关联，可以被描述为叠加褶皱（F1和F2褶皱）。F_2褶皱致密直立，是东西向水平缩短的结果。剪刀...
AbstractThis paper describes the tectono-metamorphic evolution of a segment of the Precambrian deep crust, in the southern Madagascar island. This crust corresponds to an Archaean basement reworked by a widespread, late panAfrican event (550–580 Ma) during the formation of the Mozambican belt. The finite geometry and associated metamorphism are depicted by satellite imaging, field mapping and P-T estimations using both conventional thermobarometric methods and TWEEQ software program with internally consistent thermodynamic data and uniform set of solution models. The structural pattern developed during high-grade metamorphism shows the juxtaposition of domains with complex fold geometries separated by a 15 km wide ductile shear zone. Within the folded domains, kilometre scale interference patterns associated with strongly dipping metamorphic stretching lineations can be described as superposed folding (F1 and F2 folds). The tight and upright F2 folds result from East-West horizontal shortening. The shear ...