| 周永璋,敬成贵.北京密云平顶山铬铁矿床深源成因机制的研究[J].地质找矿论丛,1988,(2):12-21 |
| 北京密云平顶山铬铁矿床深源成因机制的研究 |
| A STUDY ON THE DEEP-SOURCE ORIGIN OF THE PINGDINGSHAN Cr-Fe ORE DEPOSIT IN MIYUN, HEBEI PROVINCE |
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| DOI：10.6053/j.issn.1001-1412.1988.2. 002 |
| 中文关键词: 两期侵入 地幔残留再熔融 对称分异 |
| 英文关键词: |
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| 中文摘要: |
| 密云平顶山含铬铁矿超镁铁岩体是残留上地幔岩进一步熔融的方辉橄榄岩岩浆两次沿深断裂侵入于前寒武系黑云斜长片麻岩层间成岩。对称结晶分异作用,使铬铁矿呈浸染状沿着岩体中心相早期形成的致密状矿石,对称聚合富集成矿。 |
| 英文摘要: |
| The ultramafic rocks in Pingdingshan deposit are the magmatic intrusives with two stages and the charactenstics of symmetrical cnystalline differentiation The chromite bed occurred in saxonite of central petrographic facies(the first stage) and dunite(the second stage). Pingdingshan rock body is formed from the mantle relicts, being left after the basaltic melt mass were melted out, which intruded into Archean biotite-plagioclase-gneiss as ultramafic melt mass (saxonite) after further melting. The forming temperature is around 1305℃, and solid diagenesis took place at the depth of 10 km below the crust. This ultramafic rock body of Pingdingshan type occurred as groups and zones in the deep postition of the continental plate or near the rifts. The proper melting percentage made a great deal of Cr2 O3 in mantle relicts melted out. The suitable diagenesis depth resulted in better differentiate crystalline which enriched the chromite. Massive ores are formed in early magma, and various disseminated ores formed in late magma. |
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