豫北金斗山磁铁矿矿床地质特征及成因分析

The Geological Characteristics and Genesis of Jindoushan Magnetite Depost in Northern Henan Province

金斗山磁铁矿为济源-沁阳鞍山式铁矿、铁山河式铁矿成矿带西段新发现的铁矿床。主要赋矿地层是新太古界登封岩群,围岩为黑云角闪片岩和斜长角闪片岩。已发现7层隐伏矿体,呈层状、似层状,矿石结构为半自形-它形粒状,矿石构造有浸染状、条带状。地面高精度磁测和EH4结果显示,矿体赋存深度由西往东部逐渐加深,断层在EH4剖面上呈现出“低阻”异常特征位置推测为含铁岩系综合反应,为进一步的勘查工作提供了可靠依据。结合矿体及其围岩结构构造特征,认为金斗山磁铁矿矿床类型属于火山沉积变质型铁矿床。

Jindoushan magnetite is a newly discovered iron ore deposit in the western part of Jiyuan-Qinyang Anshan-type iron ore deposit and Tieshanhe-type iron ore metallogenic belt.The Neoarchean Dengfeng Group is the main ore-hosting strata in the study area,the host rocks are biotite amphibolite schist and plagioclase amphibolite schist.Seven layers of magnetite have been found are concealed ore bodies,ore bodies occur in irregular layered and quasi-layered formations,ore structure is semi-automorphic-it-shaped granular and ore structures are disseminated and banded.The results of ground high precision magnetic survey and EH4 show that the occurrence depth of ore body gradually deepens from west to east and the"low resistivity"anomalous feature on EH4 profile is presumed to be a comprehensive reaction of iron-bearing rock.These provide a reliable basis for further exploration work.According to the structural characteristics of the orebody and its surrounding rock,it is considered that the Jindoushan magnetite deposit belongs to volcanic sedimentary metamorphic iron deposit.