内蒙古索伦山地区地幔橄榄岩中豆荚状铬铁找矿前景

The Ore-search Prospect for Podiform Chromite Deposit in Mantle Peridotite in the Solonker Area,Inner Mongolia

产于内蒙古索伦山缝合带蛇绿岩中的铬铁矿,其深入研究对于铬铁矿的勘查、缓解铬铁矿需求紧张、增加战略矿产资源以及国民经济的发展,意义重大。本文对内蒙古索伦山地区铬铁矿进行了系统的调查和研究,在此基础上,总结了索伦山地区铬铁矿矿床地质特征,探讨了索伦山地区铬铁矿矿床的成因,评价了在索伦山地区铬铁矿找矿远景。索伦山地区铬铁矿均分布于索伦山蛇绿岩之地幔橄榄岩内,矿体产出众多,规模大小不等,均具有成带分布、分段集中的特点。矿体产状与方辉橄榄岩-纯橄榄岩产状基本一致,矿体与围岩为渐变过渡的关系。索伦山地区铬铁矿为产出高镁型矿石类型的豆荚状铬铁矿,形成于早二叠世,产于大洋中脊的构造环境。通过对地幔橄榄岩与铬铁矿的岩石学、矿物学、地球化学研究,表明索伦山地区铬铁矿的成因为熔体-岩石反应。在索伦山地区探明铬铁矿矿化点2个,铬铁矿矿点10个,小型铬铁矿矿床10个。10个已查明的小型铬铁矿矿床表明,地表矿少,盲矿体多。据此推断,已经查明的12个铬铁矿矿(化)点有可能探到更多更大的深部工业盲矿体。索伦山含铬超镁铁岩体规模巨大,延深大于600 m,具备良好的成矿条件,是良好的铬铁矿找矿靶区,具有较好的找矿前景。

The chromite from the ophiolites of Solonker Suture Belt in Inner Mongolia.,it is of significance on the survey of chromite,relieving demand of the chromite shortage,increasing the strategy mineral resources and national economy development. In the thesis,the chromite from the Solonker area,Inner Mongolia. have been investigated and studied systematically. On that basis,sum up of basic geological characteristics of the chromite deposits from Solonker area,discuss the genesis of the chromite deposits from Solonker area,evaluate chromitesearch prospect in the Solonker area. The chromite from the Solonker area distribute in mantle peridotite of the ophiolites in Solonker area. The occurrences of ore bodies are more,the sizes of ore bodies are different. The spatial distribution of ore bodies has characteristic of zonal distribution,sectional centralizing. The occurrence of ore bodies is consistent with that of harzburgite and dunite,the relationship between them is transitional each other. The podiform chromite deposits from the Solonker area contain high levels of magnesium,that was em-placed during early Permian. and was formed in a Mid-Ocean Ridge setting. The mantle peridotite and chromite have been studied on petrology,mineralogy and geochemistry. The research results prove Melt-rock interaction is an interpretation for the origin of the podiform chromite deposits from the Solonker area. Ten small chromite deposits,ten chromite spots and two chromite mineralization spots were ascertained in the Solonker area. Ten ascertained small chromite deposits indicates that the surface chromite bodies are less and the blind chromite bodies are more. Inference on the basis,it is possible that much more and much bigger industrial deep blind chromite bodies will be ascertained in the twelve chromite（ mineralization） spots. The size of Cr-bearing ultramafic rock mass is huge,the depth of that extends to more than six hundred metres. The ultramafic rock mass has good minerogenetic conditions,that is good chromite prospecting target and there is larger and more favorable chromite prospecting potential in the ultramafic rock mass.