俯冲带含水矿物脱水动力学实验研究

The process of dehydration embrittlement of hydrous mineral is usually proposed as the most important genetic mechanisms for the presence of intermediate-depth earthquakes in subduction zones. This result is based on the hypothesis that the release of water by hydrous mineral breakdown is fast enough to trigger brittle failure, but maybe the fact is not like this. For the purpose of providing theoretical basis for the genetic mechanism of intermediate-depth earthquakes in oceanic subduction zone, We plan to study dehydration kinetics of hydrous minerals（antigorite,talc and amphibole）with the conditions of different pressure, iron content and particle size in mineral, and establish the quantitative relationship of hydrous mineral dehydration rate to pressure, iron content and particle size of mineral.?The dehydration reaction mechanisms would be explored.

含水矿物脱水致脆性破裂是俯冲带中源地震的一种最重要的成因机制，该结论建立在一个假设的基础上，即含水矿物脱水速率足够快，能触发脆性破裂，然而实际情况可能并非如此。本项目拟在不同压力、矿物铁含量以及颗粒粒径条件下开展俯冲带含水矿物（叶蛇纹石，滑石和角闪石）脱水动力学的实验研究，建立含水矿物脱水速率与压力、矿物铁含量以及颗粒粒径之间的定量关系，并探索其脱水反应机制，为俯冲带中源地震成因机制研究提供理论依据。

含水矿物的脱水与部分熔融、岩浆的形成以及俯冲带中-深源地震的孕育发生有着非常紧密的关系。本项目利用热重实验，高温高压差热实验和同步辐射实验手段开展了不同压力、矿物铁含量以及颗粒粒径条件下俯冲带含水矿物（滑石，叶蛇纹石和角闪石）脱水动力学的实验研究，计算了脱水反应的动力学参数，可能的反应模型，以及脱水反应时的流体释放速率，并将其与俯冲带有关岩石的粘性松弛速度相比，认为俯冲带含水矿物的脱水可以引起高孔隙压力导致脆性破裂，为俯冲带中源地震成因机制研究提供理论依据。