摘要
在构造变形过程中,流体控制成矿作用的机制是目前世界矿床界共同面临的问题之一。通过研究剪切变形过程中的力学-化学作用,理解剪切构造应力和流体在构造成岩成矿过程中的行为与作用是解决这一科学问题的关键环节。在花岗岩高温高压剪切变形实验的基础上,分析了实验变形的矿物反应特征及矿物反应引起的化学成分变化,讨论了矿物反应与变形的相互影响。实验结果表明,变形样品中斜长石、钾长石和辉石以脆性-塑性变形为主,石英和云母以塑性变形为主。同时流体与岩石的相互作用引起了矿物间的反应,其中钾长石、辉石发生水解作用最典型。实验变形整体受应变局部化控制,随着剪切变形加强,脆性破裂逐渐形成和发展为裂隙,应力不断释放,有金属元素沿裂隙充填,这些微观特征在实验样品中普遍存在,类似野外中的矿脉。本次实验为韧性剪切带的流变行为、化学行为和剪切作用过程提供了实验数据。
The fluid-controlling mineralization mechanism during tectonic deformation is a worldwide research focus.In order to comprehend the behavior and role of shear tectonic stress and fluids in the process of tectonic diagenesis and mineralization,it is the key to study the mechanical-chemical effects in the shear deformation process.In this study,the authors analyzed the distribution of mineral reaction and the change of chemical composition caused by the mineral reaction in experimental deformed granite samples under the condition of high temperature and high pressure and discussed interaction between mineral reactions and deformation.The results indicate that plagioclase,k-feldspar and pyroxene can endure brittle-plastic deformation,while most of the quartz and mica display plastic deformation.The hydrolysis of K-feldspar and pyroxene due to the fluid-rock interaction is the most characteristic reaction in the minerals.The strain localization dominantly controls the overall deformation in the experiment.With the strengthening of shear deformation,the brittle fracture gradually forms and develops into cracks.Thus the stress is released,and metal elements are filled along the cracks.These microscopic characteristics are common in the experimental samples,similar to features of the vein in the field.This experiment provides experimental data for the rheological behavior,chemical behavior and shearing process of the ductile shear zone.
作者
刘贵
周永胜
LIU Gui;ZHOU Yongsheng(Institute of Geomechanics,Chinese Academy of Geological Sciences/Laboratory of Neotectonic Movement and Geohazard,Beijing 100081,China;State Key Laboratory of Earthquake Dynamics/Institute of Geology,China Earthquake Administration,Beijing 100029,China)
出处
《地质通报》
CAS
CSCD
北大核心
2020年第11期1840-1849,共10页
Geological Bulletin of China
基金
国家自然科学基金项目《剪切变形过程中水-岩石相互作用的高温高压实验研究》(批准号:41972233)
地震动力学国家重点实验室开放基金《剪切变形与流体对花岗岩流变影响的高温高压实验研究》(编号:LED2017B04)。
关键词
成矿作用
构造
流体
剪切变形
高温高压
dehydration reaction
melt
interaction between reaction and deformation
high temperature and pressure
