长英质麻粒岩流变性质的实验研究

EXPERIMENTAL RESEARCH ON RHEOLOGICAL PROPERTIES OF A FELSIC GRANULITE

在温度为６５０～９００℃、围压为１１００ΜΡａ和应变率为１０－４～１０－７ｓ－１的条件下，对大陆下地壳组成中的一类重要岩石——长英质麻粒岩进行了流变实验。稳态流动力学参数符合幂函数流动律ε＝Ａｅｘｐ（Ｑｃ／ＲＴ）Δσｎ，其中Ａ＝０．２７ＭＰａ－３ｓ－１，Ｑｃ＝２８８ｋＪ／ｍｏｌ，ｎ＝３．０。该文将其外推到大陆下地壳变形环境下。

A felsic granulite from South Neimenggu(Inner Mongolia) of China has been deformed at the confining pressure of 1100 MPa, temperatures of 650～900℃, and strain rates of 10 -4 ～10 -7 s -1 . Steady state mechanical data fit well a creep power law with A =20.7 MPa -3 s -1 , Q c=288 kJ/mol and n =3.0.Extrapolation of this flow law to a range of physical condition of the continental lower crust supports the view that there is a mechanically soft zone of the continental lower crust in the continental lithosphere.