Fibrous clay mineral authigenesis induced by fluid-rock interaction in the Galera fault zone (Betic Cordillera, SE Spain) and its influence on fault gouge frictional properties
Fibrous clay mineral authigenesis induced by fluid-rock interaction in the Galera fault zone (Betic Cordillera, SE Spain) and its influence on fault gouge frictional properties
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加莱拉断层带（西班牙东南部贝蒂科迪勒拉）流体-岩石相互作用引起的纤维状粘土矿物自生及其对断层泥摩擦特性的影响
DOI：
10.1016/j.clay.2016.06.023
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发表时间：
2016
影响因子：
5.6
通讯作者：
F. García
中科院分区：
文献类型：
--
作者：
C. Sánchez;J. Jiménez;I. Abad;D. Faulkner;F. Nieto;F. García
这项研究对西班牙南部加莱拉断层带中发现的富含粘土的材料和结构进行了矿物学和力学分析，这些材料和结构是由于影响该地震活跃地区的活跃变形过程而形成的。通过 XRD、SEM、TEM 和 XRF 等一系列分析技术，发现加莱拉断裂带岩石中粘土矿物组合和化学成分存在显着差异。鉴定出三种不同的矿物组合：1）围岩组合，包括白色泥灰岩和深色黄铁矿层，后者也在注入特征中发现。它们的组合包括白云石、石膏、石英、方解石和层状硅酸盐 2) 富含蒙皂石和坡缕石的断层泥，形成于断层 NE 区域（Galera 村）地层层序上部的物质上；3) 富含海泡石的断层泥，形成于断层中央西南段地层层序下部的区域（Rambla de los皮拉雷斯）。富含纤维粘土的泥凿是由流体-岩石相互作用期间的热液蚀变形成的，集中在断层和裂缝中。其矿物学以自生富镁纤维状粘土矿物为主；海泡石，直接从富含镁的流体中沉淀出来；坡缕石是流体与富铝母岩相互作用的产物。这些富含粘土的断层泥的摩擦滑动实验数据揭示了它们的力学特性的巨大差异。在断层的东北部地区，富含蒙脱石和坡缕石的泥泥具有较低的摩擦系数（湿摩擦系数为 0.17，真空下为 0.59），其摩擦稳定性参数（a-b）值始终为正，表明可能与蠕动和稳定滑动过程有关的稳定状态。然而，在中西南段，泥岩富含自生海泡石，完全不含蒙脱石。该凿岩的较高摩擦系数（湿摩擦系数为 0.47，真空下为 0.68）和 a-b 为负值，表明存在一个更中性到不稳定的状态，可能有利于地震成核。
This study presents a mineralogical and mechanical analysis of the clay-rich materials and structures identified in the Galera Fault Zone, southern Spain that formed as a consequence of active deformation processes affecting this seismically active region. Significant differences in clay mineral assemblages and chemical composition were identified in rocks from the Galera Fault Zone, through a series of analytical techniques including XRD, SEM, TEM and XRF. Three distinct mineral assemblages were identified: 1) wall-rock assemblages including white marls and dark lutite layers, with the latter also found in injection features. Their assemblage includes dolomite, gypsum, quartz, calcite and phyllosilicates 2) smectite- and palygorskite-rich fault gouges formed on materials from the upper part of the stratigraphic sequence at the NE area of the fault (Galera Village), and 3) sepiolite-rich gouges in areas of the lower part of the stratigraphic sequence at the central SW segment of the fault (Rambla de los Pilares). Fibrous clay-rich gouges were formed by hydrothermal alteration during periods of fluid-rock interaction that was concentrated in fault planes and fractures. Their mineralogy is dominated by authigenic Mg-rich fibrous clay minerals; sepiolite, precipitated directly from an Mg-rich fluid; and palygorskite as the product of the interaction of the fluid with the Al-rich host rock. Experimental data from frictional sliding experiments on these clay-rich fault gouges reveal strong differences in their mechanical properties. Towards the north-eastern areas of the fault, the smectite- and palygorskite-rich gouge has a low friction coefficient (0.17 wet and 0.59 under vacuum) and its values of the friction stability parameter (a–b) are always positive indicating a stable regime that could be related with creeping and stable-sliding processes. In the central-south-western segment, however, the gouge is rich in authigenic sepiolite and presents complete absence of smectite. The higher friction coefficient (0.47 wet and 0.68 under vacuum) and negative values of a–b for this gouge suggest a more neutral to unstable regime that could favour earthquake nucleation.
挖出的地壳断层带的热液蚀变：测试智利北部阿塔卡马断层系卡莱塔科洛索断层的地球化学活动性
影响因子：
2.9
作者：
Arancibia G
通讯作者：
Arancibia G