How deformed are weakly deformed mudrocks? Insights from magnetic anisotropy
How deformed are weakly deformed mudrocks? Insights from magnetic anisotropy
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DOI：
10.1144/gsl.sp.2004.238.01.13
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
J. Parés
中科院分区：
文献类型：
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作者：
J. Parés
磁化率各向异性在岩石组构研究中的应用已有三十多年。我们对变形岩石中磁组构形成机制的认识已经有了很大的提高，尽管一些细节仍在争论之中。本文综述了AMS研究在泥岩早期变形阶段表征中的应用进展。从低温低压变形岩石的AMS现有数据集，有可能重新讨论弱变形岩石的概念。我们认为，泥岩中的弱变形和磁性隐组构的出现是串联的。此外，弱变形岩石的磁各向异性研究表明，解理组构，变形泥岩中最常见的平面组构，逐渐建立从变形的最早阶段，而不是突然在一些应变阈值。
Abstract For over thirty years the anisotropy of magnetic susceptibility (AMS) has been exploited in rock fabric studies. Our knowledge of the mechanisms leading to magnetic fabric development in deformed rocks has grown substantially, even though some details are still under debate. This paper reviews recent developments in AMS studies applied to the characterization of early deformation stages in mudrocks. From the current data set of AMS in rocks deformed at low temperature and low pressure it is possible to revisit the concept of weakly deformed rocks. We contend that weak deformation in mudrocks and the appearance of magnetic cryptofabric are concatenated. Furthermore, magnetic anisotropy studies in weakly deformed rocks suggest that cleavage fabric, the most common planar fabric in deformed mudrocks, builds up gradually from the earliest stages of deformation rather than suddenly at some strain threshold.