湘赣边中新生代走滑断裂带的流体-岩石相互作用──以长寿街-双牌断裂和遂川-热水断裂为例

INTERACTION BETWEEN FLUID AND ROCK OF MESOZOIC-CENOZOIC NNE-TRENDING STRIKE-SLIP FAULT ZONE,BORDER REGION BETWEEN EASTERN HUNAN AND WESTERN JIANGXI PROVINCES,CHINA:WITH THE CASE STUDY OF CHANGSHOUJIE-SHUANGPAI AND SUICHUAN-RESHUI FAULTS

湘赣边地区自晚三叠世开始进入了全新的陆内走滑造山作用阶段，并经历了从会聚走滑向离散走滑的构造性质转换，野外地质调查、显微构造研究、流体包裹体和构造岩岩石化学分析资料均表明，走滑断裂带内有大量的流体活动，且不同变形时期及同一变形期不同变形环境的流体作用及其形成的主要构造特征均有很大差异，对变形岩石的成分变异和体积变化计算结果显示，走得变形过程中的流体（质量）／岩石（体积）比率可达105g／m3量级，这种大规模的流体活动对区域热液铀成矿具有重要的作用.

The border region between eastern Hunan and western Jiangxi provinces has experienced since Late Triassic both the intracontinental strike-slip orogeny and the structural transformation from convergent strike-slip (T1 - J ) to divergent strike-slip (K - E1 ). The field investigation, research into the microstructure, and petrochemical analysis of the fluid inclusions and structural rock samples, show that a great nurnber of fluid flows are present within the strike-slip fault zones, and that large differences arise in fluidrock interactions and the resulting major structural features between different deformation stages and between different deformation environrnents in the same deformation stage. The specific volume variations and fluid/rock ratios of the deformation rocks in the divergent strike-slip stage can be calculated as follows: The ductile rocks are characterized by volume loss and the corresponding fluid (mass) /rock (volume) ratios are (3. 96 -50. 4) × 104 g/m3, but the brittle rocks are characterized by dilation (with the dilation rate reaching 30% ),and the corresponding fluid/rock ratios are 5 - 40 g/m3. The compositional change of the deformed rocks and the calculation results of the volume variations beth show that the fluid (mass)/rock (volume) ratio in the strike-slip deformational rocks may have rcyched 105 g/m3. This kind of large-scale fluid-rock interaction in the strike-slip deformation may have had a great effect on the regional hydrothermal uranium mineralization.