鲁西潘店地区矽卡岩型铁矿成矿规律初探

Primary Study on Metallogenic Regularity of Skarn Type Iron Deposit in Pandian Area in Western Shandong Province

摘要:

近年来，在鲁中隆起区西北部潘店地区的铁矿勘查工作取得了重大进展。该区发育有明显的航磁异常及航空重力异常，且具有“重磁同源性”特征；通过对航磁异常的分析，可分为李屯、潘店、大张和薛官屯4个次级磁异常。勘查工作表明，区内巨厚新生界覆盖层下发育有矽卡岩型铁矿床，总体表现为“地层、岩体和构造”联合控矿的特征，即铁矿体受控于奥陶纪马家沟群碳酸盐地层、中生代燕山晚期闪长岩体、以及地层与岩体接触处形成的各种类型（构造）接触带。区内铁矿体赋存位置多样，主要为接触带赋存式、断裂充填式、层间充填式、裂隙贯入式、捕虏体构造式等；其成矿时代为早白垩世（130～131Ma），与济南、莱芜、金岭地区矽卡岩型铁矿形成时代基本一致；铁矿物质主要来源于中—基性侵入岩体。在整体表现为具有（剩余）重力异常高值处、（化极）磁异常明显部位，以及高—低电阻率转换带的地段进行铁矿勘查工作较为有利。

Abstract:

In recent years, significant progresses has been made in iron ore exploration in Pandian area in northwest of Luzhong uplift. There are obvious aeromagnetic anomaly and airborne gravity anomaly in this area, and have the characteristics of "homology of gravity and magnetism". Based on the analysis of aeromagnetic anomaly, it can be divided into 4 secondary magnetic anomalies, they are Litun secondary magnetic anomaly, Pandian secondary magnetic anomaly, Dazhang secondary magnetic anomaly and Xueguantun secondary magnetic anomaly. As showed by the exploration result, the skarn type iron deposits are buried in the thick Cenozoic covered area. In general, iron orebodies in the region have the combined orecontrolling characteristics with "strata, intrusive rock and structure", that is, iron orebodies are controlled by Ordovician Majiagou group carbonate strata, the diorite of late Mesozoic Yanshan period, and various types of contact zones (structures) of the strata and intrusive rock. There are several occurrences of iron orebodies in the region, such as contact zone occurrence type, fault filling type, interlayer filling type, fissure penetration type, and xenolith structure type. The metallogenic epoch of iron deposits is early Cretaceous (130～131Ma), which is basically consistent with metallogenic epoch of skarn type iron deposit in Jinan, Laiwu and Jinling areas. The iron ore material mainly comes from mediumbasic intrusive rock. It is suitable to carry out iron ore exploration in the areas of high (residual) gravity anomaly, high (pole) magnetic anomaly, and the transition zone of highlow resistivity.