【摘要】 俯冲带变质脱水作用对俯冲带的流体形成、岩浆起源和演化起着重要的控制作用。泥质岩是俯冲板块表层沉积物的典型代表,本文以天然泥质岩为对象,成功运用高压差热分析(HP-DTA)方法对其在1．5-4．0GPa下的脱水温度进行了实验研究。结果表明,泥质岩的脱水温度与压力呈很好的负相关关系。通过与冷、热俯冲带地热梯度线比较,确定了泥质岩在俯冲带深部发生变质脱水作用的深度范围(75-145 km),为岛弧岩浆源区位置的解释提供了实验证据。更多还原

【Abstract】 Metamorphic dehydration in subduction zones plays a significant role in the genesis of slab-derived fluids and the generation and evolution of arc magmas. Because pelite is the typical representation of sediments within the upmost part of subducted slabs, it has been chosen as the starting materials for the experimental studies on the dehydration temperatures under high pressures from 1.5 to 4. 0GPa by high-pressure differential thermal analysis (HP-DTA). The result shows that the dehydration temperatures have a closely negative linear correlation with the corresponding pressures. The comparison between this result and the general geothermal gradients in subduction zones worldwide suggests that the depth at which the metamorphic dehydration of pelite occur in subduction zones varies mostly in the range from 75 to 145km, which provides further experimental evidence for the location of arc magma origin.更多还原