Mode of occurrence, bulk chemical compositions, and mineral textures of ultramafic rocks in the Lutzow-Holm Complex, East Antarctica
Mode of occurrence, bulk chemical compositions, and mineral textures of ultramafic rocks in the Lutzow-Holm Complex, East Antarctica
复制标题
东南极洲 Lutzow-Holm 杂岩中超镁铁质岩石的赋存模式、大量化学成分和矿物结构
DOI：
--
复制
发表时间：
1986
期刊：
影响因子：
--
通讯作者：
K. Kizaki
中科院分区：
文献类型：
--
作者：
Y. Hiroi;K. Shiraishi;Y. Motoyoshi;S. Kanisawa;K. Yanai;K. Kizaki
总结了晚元古代高品位Lutzow-Holm杂岩中超镁铁岩（超基性岩+“规范”超镁铁岩（规范橄榄石+辉石+钛铁矿>70%））的产状、体相化学成分和矿物结构的现有资料。整体化学成分表明，它们大多来自层状辉长岩的不同部位。有些是斜长石，主要由规范的橄榄石和斜长石组成，不含辉石。现场的产出模式表明，它们是构造断裂的，并侵位在变质沉积片麻岩中。它们主要出现在Li.itzow-Holm杂岩的西部，表明原始辉长岩块体存在于目前缺失的部分（海底？）在相邻的Li.itzow-Holm和Yamato-Belgica复合体之间。矿物结构，特别是石榴石和尖晶石，表明Meta变质条件的尖晶石-角闪石二辉橄榄岩相岩石的结晶重结晶过程中，从早期的相对高压和低温的结晶条件，后来的低压和高温条件。
Available data on the mode of occurrence, bulk chemical composi tions, and mineral textures of ultramafic rocks (ultrabasic rocks plus "normatively" ultramafic rocks (normative olivine+pyroxenes+ilmenite>70%)) in the Late Prot erozoic high-grade Lutzow-Holm Complex are summarized. The bulk chemical compositions suggest that most of them are derived from various parts of layered gabbro. Some are troctolitic, being composed mainly of normative olivine and plagioclase without pyroxenes. The mode of occurrence in the field suggests that they were tectonically fractured and emplaced in the metasedimentary gneisses. Their occurrence mainly in the western part of the Li.itzow-Holm Complex suggests that original gabbroid masses were present in the presently missing part (ocean floor?) between the adjacent Li.itzow-Holm and Yamato-Belgica Complexes. The mineral textures, especially those of garnet and spinel, suggest changing meta morphic conditions within the spinel-amphibole lherzolite facies during prograde recrystallization of the rocks; from earlier relatively high-pressure and low-temper ature conditions to later lower-pressure and higher-temperature conditions.