• 责任者：Chen Shizhong (Nanjing Institute of Geology and Mineral Resources ; China Geological Sunvey ; Nanjing 210016 ; China) ; Zhu Xiaoting
• 刊名：Geology in China
• 出版年：2013
• 卷期：40(6)
• 关键词：铬铁矿矿床 ; chromite deposit ; 河北 ; Hebei Province
• 页码：p.1912-1924
• 图表：7 illus., 2 tables, 73 refs.
• 分类号：1001
• issnNo：ISSN1000-3657
• isbnNo：CN11-1167/P

     Gangshang ultramafic rocks are mainly composed of garnet peridotites and dunite, which contain o/ivine, chromium spine/, diopside, endiopside, or/and garnet, orthopyroxene, amphibole and phlogopite. Chromium spinels in Gangshang ulttamatic rocks are composidonaily variable, with Cr# （molar100Cr/（Cr＋Al）） varying from 51 to 89, and are associated with four stages of ultramafic rocks. With the increase of Cr# in chrome spinels Mg# （molarl00Mg/（Mg ＋Fe^2＋））of chromium spinets decreases,whereas oxygen fugacity increases, as reflected by the composition of Gangshang chromium spinels. In the process of retrometamorphism of amphibole-facies and greemchist-facies, Cr, Mg and A1 of chromium spinels decrease, whereas Fe rehtively increase. In addition, Gangsbang ultramafic rocks experienced shearing reformation and CO metasomatism, which was helpful to the enrichment of chromium and the formation of chromium spinel. This mechanism is also useful to understanding the development of chromite deposits in some metamorphic areas and the enrichment of some chromite ore bodies.