Abstract

The microstructure and composition of accessory chromian spinels from peridotite and ore-forming chromian spinels from disseminated ores in dunite near the boundary between the mantle and crustal ophiolite sequences are studied. Application of the method of backscattered electron diffraction (EBSD) demonstrated an existence of microtextural heterogeneity of individuals, expressed in a domain (subgrain) structure, which is caused by plastic deformation and recrystallization of mineral grains. It is shown that the formation and growth of new chromian spinel grains proceeded synkinematically in the solid state due to the segregation of aluminum and chromium in the composition of rock-forming silicates. It is concluded that the microstructural patterns of chromitite were formed under the influence of two simultaneous processes: (1) a decrease in the grain size via translational sliding and dynamic recrystallization and/or (2) the growth of recrystallized grains and their aggregation.

中文翻译：

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南乌拉尔克拉卡地块蛇绿铬铁矿的微观结构模式。一、带状散布矿石

摘要

研究了靠近地幔与地壳蛇绿岩序列边界的纯岩中橄榄岩副铬尖晶石和浸染矿石成矿铬尖晶石的显微结构和组成。背散射电子衍射（EBSD）方法的应用表明个体的微观纹理异质性存在，表现为域（亚晶粒）结构，这是由矿物颗粒的塑性变形和再结晶引起的。结果表明，由于造岩硅酸盐成分中铝和铬的偏析，新铬尖晶石晶粒的形成和生长在固态下以同运动方式进行。得出的结论是，铬铁矿的微观结构模式是在两个同时过程的影响下形成的：