山东省苍峄铁矿带后期改造与找矿方向分析

Analysis on Late Reformation and Prospecting Direction of Cangyi Iron Ore Belt in Shandong Province

苍峄铁矿带为山东省典型的“鞍山式”铁矿成矿带,其后期改造作用剧烈,控矿因素复杂。带内先后发现和评价了多个大、中型铁矿床,现区内露头及浅部矿体已基本查明,探求铁矿石资源量逾9亿t,仍未完全控制该矿带的延长和延深规模,其深部及外围隐伏资源潜力巨大。以往勘查工作侧重于各区段浅部矿体特征和规模的控制评价,对矿带赋存规律和找矿方向的研究存在不足。该文结合矿带内已查明矿床特征,对区内基底褶皱构造和断层构造开展了分析研究。基于褶皱控矿理论,将苍峄铁矿划分为5个主含矿带,以次级截矿断层为界,将各含矿带自西向东分为3个区段。从断层构造对控矿褶皱及含矿带的后期改造入手,对原始控矿褶皱进行了恢复重建。验证了太白向斜、石闫背斜、辛庄向斜和后大窑背斜为连续产出的复式褶皱,因褶皱构造向西倾伏,致使辛庄向斜向东剥蚀缺失,石闫背斜和后大窑背斜向西隐伏深潜,并有继续向西延伸的可能。进而分析了区内找矿远景,划分3个赋矿远景区,指明了该区今后的重点找矿方向。

Cangyi iron ore belt is a typical “Anshan-type” iron ore metallogenic belt in Shandong province. Its late formation is strong and ore-controlling factors are complex. Several large and medium size iron deposits have been discovered and evaluated in the belt. The outcrop and shallow ore bodies in the area have been basically identified. The iron ore resources are more than 900 million tons, and the extension and the scale of the ore belt have not been fully controlled. Its deep and peripheral hidden resources have great potential. The former exploration work focused on the control and evaluation of the characteristics and scale of the shallow ore bodies in each section, and the study on the occurrence rule of the ore belt and the prospecting direction is insufficient. In this paper, the fold structure and fault structure in the basement of the area with the identified characteristics of the deposits in the ore belt have been analyzed and studied. Based on the theory of fold control, Cangyi iron ore is divided into five main ore belts, and the ore-bearing belt is divided into three sections from west to east which border the secondary fault of cutting ore. Based on the late formation of the fault structure to the ore-control folds and the ore-bearing belt, the original ore-control folds have been restored and reconstructed. It is verified that Taibai syncline, Shiyan anticline, Xinzhuang syncline and Houdayao anticline are continuous output multi-folds. The fold structures are tilted to the west which caused Xinzhuang syncline to the east absent, Shiyan syncline and Houdayao anticline concealled and dived deep into the west. It also has the possibility of continuing to extend westward. Prospecting prospects in the area have been analyzed and divided into three prospecting areas. Key prospecting direction in this area has been pointed out in the future.