东秦岭地区木龙沟铁矿地质特征及找矿方向

木龙沟铁矿作为典型的矽卡岩型铁矿,其地质特征与典型的矽卡岩型铁矿无异。围岩为含MgO较高的白云岩,磁铁矿通常直接存在于外接触带的镁矽卡岩中。这些磁铁矿体主要分布在透辉石-镁橄榄石矽卡岩和硅镁石矽卡岩中,呈现为透镜状、似层状或不规则状等的成群分布。此外,在蛇纹石化的白云石大理岩中可少见到磁铁矿体。磁铁矿体的大小通常与周围镁矽卡岩的发育程度成正相关。锆石U-Pb定年结果表明,木龙沟花岗闪长岩的成岩年龄为146.1±0.5 Ma(n=21,MSWD=0.48),推测矿床形成时间可能略晚于146.1 Ma。围岩蚀变现象为此类型矿床的主要找矿标志,因此,了解本区矽卡岩型铁矿的地质特征和找矿标志对于理解成矿模式和找矿方向可以提供一定的帮助。

As a typical skarn iron ore,Mulonggou Iron Mine has the same geological characteristics as the typical skarn iron ore.The surrounding rock is dolomite with high MgO content,and magnetite usually exists directly in magnesium skarn in the outer contact zone.These magnetite orebodies are mainly distributed in diopside-magnesite skarn and magnesite skarn,showing lenticular,layered or irregular distribution.In addition,magnetite orebodies are rarely seen in serpentinized dolomite marble.The size of magnetite bodies is usually positively correlated with the development level of surrounding magnesium skarns.The zircon U-Pb dating results indicate that the diagenetic age of the Mulonggou granodiorite is 146.1±0.5 Ma(n=21,MSWD=0.48),suggesting that the formation time of the deposit may be slightly later than 146.1 Ma.Wall rock alteration is the main prospecting indicator of this type of ore deposits.Therefore,understanding the geological characteristics and prospecting criteria of skarn iron deposits in this area can provide some help to understand the metallogenic model and prospecting direction.