Abstract

The work reports on the results of the mineralogical and petrographic study of the Borodino meteorite (H5). For the first time, meteorite minerals were described and their chemical compositions were given. The following were found in the Borodino meteorite: olivine (Fa 18.16 ± 1.15), Ca-poor pyroxene – (clino)enstatite (En 81.37 ± 1.73, Wo 1.18 ± 0.31), Ca-rich pyroxene – augite (En 57.23 ± 1.57, Wo 39.38 ± 2.68), diopside (En 51, Wo 45), pigeonite (En 69, Wo 6), plagioclases – oligoclase (An 12.16 ± 1.24, Or 5.68 ± 2.12), andesine (An 48.23 ± 1.84, Or 1.23 ± 0.12), anorthoclase (An 0, Or 36) and sanidine (An 0, Or 40.00 ± 1.1), and poorly crystallized glasses of the feldspathic composition, merrillite and chromespinelide. The obtained data made it possible to estimate a degree of terrestrial weathering of the meteorite as W0 and the stage of impact metamorphism (S1-2), which suggests good preservation of the meteorite material. The composition of olivine and Cr-spinel, determined by the Electron Probe Microanalysis, was used to estimate the peak temperature of thermal metamorphism at 720°C, which falls within the temperature range (670–740°C) typical of chondrites of a petrological type 5. The presence of Ca-rich pyroxenes, large grains of Ca–Na–Mg phosphates and chromite-pigeonite aggregates in the meteorite matrix indicate the prolonged heating of the material.

中文翻译：

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博罗季诺陨石：母体的进化

摘要

该工作报告了博罗季诺陨石（H5）的矿物学和岩石学研究结果。首次描述了陨石矿物并给出了它们的化学成分。在博罗季诺陨石中发现了以下物质：橄榄石 (Fa 18.16 ± 1.15)、贫钙辉石 – (斜)顽辉石 (En 81.37 ± 1.73、Wo 1.18 ± 0.31)、富钙辉石 – 辉石 (En 57.23 ± 1.57、 Wo 39.38 ± 2.68)、透辉石 (En 51、Wo 45)、变长石 (En 69、Wo 6)、斜长石 – 寡长石 (An 12.16 ± 1.24、或 5.68 ± 2.12)、中长石 (An 48.23 ± 1.84、或 1.23 ± 0.12) )、正长石 (An 0, Or 36) 和透长石 (An 0, Or 40.00 ± 1.1)，以及长石组合物、美瑞长石和铬尖石的低结晶玻璃。获得的数据可以估计陨石的陆地风化程度（W0）和撞击变质阶段（S1-2），这表明陨石材料保存良好。通过电子探针微量分析测定橄榄石和铬尖晶石的成分，用于估计热变质作用的峰值温度为 720°C，该温度范围属于岩石学球粒陨石的典型温度范围 (670–740°C)。类型 5。陨石基质中存在富钙辉石、大颗粒 Ca-Na-Mg 磷酸盐和铬铁矿-鸽铁矿聚集体，表明材料的加热时间较长。