| 对富铝型豆荚状铬铁矿矿床成因的新认识一一以新疆萨尔托海铬铁矿矿床为例 |
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| 引用本文：.1990.A new idea about the genesis of the aluminium rich podiform chromite deposit—with theSartuohai chromite deposit of Xinjiang as an example[J].Mineral Deposits,9(2):97~111 |
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| 中文摘要:萨尔托海铬铁矿矿床产于萨尔托海蛇绿岩块的地幔橄榄岩中，属于富铝型豆荚状铬铁矿床。该矿床与一套橄长岩和辉长岩类岩石紧密伴生，矿体周围常被一薄的绿泥石壳所包裹。本区铬铁矿的形成包括两个阶段：第一阶段是原始地幔岩经高度熔融形成富铬铬铁矿；第二阶段形成富铝铬铁矿。交代作用伴随着新生单斜辉石和斜长石的形成。原始地幔岩的高度熔融以及基性熔体在地幔橄榄岩中的形成和存在是萨尔托海铬铁矿形成的先决条件。 |
| 中文关键词:原始地幔岩高度熔融 富铬铬铁矿 基性熔体交代 富铝铬铁矿 萨尔托海 |
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| A new idea about the genesis of the aluminium rich podiform chromite deposit—with theSartuohai chromite deposit of Xinjiang as an example |
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| Abstract:The Sartuohai chromite deposit occurs in the mantle peridotite of the Sartuohai ophiolite block. The Cr2O3 and A12O3 contents of the chromite ores vary from 37 to 45％ and from 20 to 31％ respectively, indicating that the deposit is a Al-rich podiform chromite one. Like other Al-rich chromite deposits,the Sartuohai chromite deposit is intimately associated with a suite of troctolite, and gabbroid which has a close genetic connection with the chromite deposit. In addition, the chromite orebodies are generally enclosed with a thin crust of chlorite. The formation of the Al-rich chromite in this area comprises two stages. During the first stage, the ore-forming materials rich in chromium(Cr-rich chromite)were formed by the high-degree melting of the primary pyrolite and the melting was accompanied by two parallel modification and reformation processes: the Mg×100/(Mg+Fe2+)ratio of the silicate minerals (Ol, Opx, Cpx)progressively rose with the gradual heightening of the degree of melting: the Cr×100/(Cr+Al)ratio of the accessory spinel also successively rose with the gradual heightening of the degree of melting. At the second stage, the Cr-rich chromite was replaced by the basic melt, giving birth to the Al-rich chromite deposit. The replacement was also accompanied by the formation of the new-born clinopyrobxene and plagioclase. Therefore, the high-degree melting of primary pyrolite and the formation and preservation of the basic melt in the peridotite also make up the prerequisite for the formation of the AI-rich chromite deposit in Sartuohai. |
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