The ophiolite massifs are composed of mantle peridotite that is mainly harzburgite and dunite , and lacked of crust magmatite within the typical ophiolite suite 摘要该蛇绿岩带的岩体由地幔橄榄岩组成,主要岩石类型是方辉橄榄岩和纯橄榄岩,缺少典型蛇绿岩剖面中的洋壳单元。
2.
The complex electrical properties of dunite were measured over the frequency range from 0 . 1 - 106hz , at 1 - 3 gpa and 1282 - 1544k , and at the fo2 of mo - moo2 . complex plane plots show separate effects of grain interior and grain boundary conductivity 对颗粒边界的电导率研究表明,颗粒边界的电导率高于颗粒内部的电导率,总电导率则小于颗粒内部和颗粒边界的电导率,颗粒边界并没有增强总电导率。
3.
Secondly , based on the microbeam analytical technique , on the one hand , through investigating the characteristic of major elements in the mantle minerals the author acquired the static information from mantle ; on the other hand , through multi - point analysis of a part of the minerals from mantle , the auther got dynamic information from mantle . finally , generalizating the fruits of this study and predecessors , the autor holds that the constituents of lithospheric mantle possibly includes spinel lherzolites , clinopyroxenites , websterite , dunite , harzburgites , garnet lherzite , phlogopite lherzite , eclogites , clinopyroxene megacrysts ; compared with east china and north china platform , the research field mantle shows the characteristics of higher degree of partial melting processes and more depleted mantle ; the . upper mantle beneath north hetian area is heterogeneous , with a tendency of deficit in a12o3 and lree from kaliyang in west hetian to the river basin of kalakshi river and yulongkashi river ; the subduction of the crust beneath north hetian has ever occurred in geological history and caused the mixing of mantle - crust ; the depth of the origination of basaltic magmas beneath north hetian exceeds 73km ; the thickness of the lithosphere beneath the research area amounts to 204 . 9km ; the mantle beneath north hetian has geological condtions for forming diamond deposits 最后,综合本区幔源矿物和地幔岩石的特征以及地球物理资料,得出如下结论:本区上地幔的物质组成有尖晶石二辉橄榄岩、二辉岩、单斜辉石岩、纯橄榄岩、方辉橄榄岩、石榴石二辉橄榄岩、金云母二辉橄榄岩、榴辉岩;与中国东部以及华北地台上地幔相比,研究区上地幔具有富集主元素中相容元素和亏损其中的不相容元素的特征,局部熔融程度较高;上地幔存在横向和纵向的不均一性,从西部的克里阳到喀拉喀什河和玉龙喀什河流域, al和lree富集程度呈下降趋势,不同来源的相同矿物中主元素的含量差异较大;地质历史时期这里可能发生过地壳俯冲并产生壳幔混合作用;玄武岩浆的起源深度73km ;从幔源重砂矿物的温压估算结果,可以推断出岩石圈厚度可达204 . 9km ;综合岩石圈物质组成特征、岩石圈热状态、地幔温压状态、氧逸度以及幔源岩石和幔源矿物的化学成分,认为研究区具备了金刚石成矿地幔地质条件。
4.
Electrical conductivities of quartz , olivine , dunite , iherzolite , pyroxenite , and megaaugite were measured by virtue of the new system ; whereas , the electrical conductivity of gabbro was measured by means of the old one . an interesting outgrowth of the present study is the measurement of the complex impedance of a series of quartz plates with different orientations 石英(人造水晶) 、橄榄石、纯橄榄岩、辉石岩、二辉橄榄岩、巨晶辉石的电导率测量是在新的测量系统下获得的,而辉长岩的电导率测量是基于lcr仪为测量仪器的测试系统下获得的。