摘要
在固体地球中,水虽微量,但对众多地质过程(例如,岩石部分熔融与火山喷发、地震活动等)和岩石的物理化学性质(例如,电导率、滞弹性、地震波性质、相变动力学等)影响重大。更为重要的是,水能通过影响矿物的变形机制来控制岩石的流变强度,进而制约着地球动力学的过程。名义无水矿物(NAMs:Nominal anhydrous minerals)即为分子式中不含氢的矿物,其晶格的容水量远小于正常含水矿物(如,角闪石,蛇纹石等)的容水量,但由于NAMs在固体地球中体积比例甚大,仅上地幔的橄榄石中所能溶解的水可能比全部地表水还多。因此了解水对NAMs(尤其是分别作为地壳和上地幔主要组成矿物的石英和橄榄石)变形的影响对于精确地构建岩石圈强度剖面和深刻理解构造地质学与地球动力学过程至关重要。本文将系统地回顾水对NAMs变形的影响,首先通过回顾水在固体地球内部的存在形式提出了NAMs是固体地球中的重要水库,接着阐述了NAMs中水的存在形式、溶解机制、溶解度影响因素及扩散动力学,最后着重论证了水致弱化在石英和富镁石榴石中最强,然后依次是单斜辉石、长石、橄榄石,瓦德利石和林伍徳石。
Even though water exists as a trace component in the solid Earth, it exhibits significant influences on the physical and chemical properties of crust and upper mantle minerals and rocks （e. g. , melting temperature, electri- cal conductivity, anelasticity, elastic wave, rheological properties, and transformation kinetics） , and hence play important roles in many geological processes （e. g. , partial melting, volcanism and earthquake）. Particularlly, water controls tectonic evolution and geodynamics on the earth by affecting the strength and deformation mechanisms of minerals and thus the rheology of rocks. Nominally anhydrous minerals （NAMs） , a type of minerals which have no H in their chemical formulae, can dissolve significant amount of water or hydrogen. Although the concentration of water in NAMs is much less than that in hydrous minerals （e. g. , amphibole, serpentine, etc. ） , the amount of water dissolved in NAMs in the Earth is quite huge because they constitute most volume of the earth. Even only oli- vine, can dissolve more water than the seas. Understanding the influence of water on the deformation of NAMs, es- pecially quartz and olivine which are the main constitutes of the crust and the upper mantle, respectively, is thus essential for modeling precisely the strength envelope of lithosphere and understanding its tectonic evolution and ge- odynamics. This paper provides a systematic summary for the influence of water on deformation of NAMs. We firstly introduce NAMs through reviewing the existence forms of water inside the earth and proposing that NAMs are impor- tant reservoirs for water in the solid earth; then present the dissolution mechanisms of water, influential factors of solubility and diffusion kinetics of water in NAMs ; and finally emphasis on a detailed description that water weake- ning in quartz and magnesium-rich garnet is the strongest and it decreases successively in clinopyroxene, feldspar, and olivine, but water weakening in wadsleyite and ringwoodite is the weakest.
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2013年第1期138-163,共26页
Geotectonica et Metallogenia
基金
国家自然科学基金项目(批准号:41174072,41090373,40772029,41102139)
中国科学院知识创新工程重要方向项目(编号:KZCX2-YW-Q08-03-4)
中国科学院“百人计划”项目(编号:KZCX-0733221A07)
青藏高原东部和东南部岩石圈流变学及地球物理性质研究项目(编号:1212011121274)联合资助
