豫西寨凹隐伏岩体地球物理场特征与深部找矿预测

Geophysical Field Characteristics and Deep Ore Prospecting Prediction of the Zhaiwa Concealed Rock Mass in Western Henan

寨凹隐伏岩体是豫西南地区利用重磁资料解释推断的8个隐伏、半隐伏岩体之一,分布面积约310km^2。豫西南地区主要钼(钨)铅锌银(金)矿床均分布于这8个隐伏、半隐伏岩体区及其边部附近,二者具有非常明显的时空关系。研究隐伏岩体分布形态、深度、产状和深大断裂构造分布,对指导深部找矿勘探具有重要意义。通过研究寨凹隐伏岩体重、磁场变化特征和分布规律,并通过相关定量计算,确定了隐伏岩体的侵入模型。将全区隐伏岩体分为三个区,Ⅰ区隐伏岩体顶面深度0~0.8km,分布面积约71km^2;Ⅱ区隐伏岩体顶面深度0.8~2.0km,分布面积约153km2;Ⅲ区隐伏岩体顶面深度2~4km,分布面积约86km^2。根据隐伏岩体侵入模型和典型矿床物探异常特征,建立了立体成矿模型(从浅至深、从中低温成矿元素到高温成矿元素的过渡模型)和综合地球物理找矿模型(包括隐伏岩体、隐伏岩体顶上带、岩钟和斑岩体、矿体矿化体的地球物理异常标志);预测了找矿潜力,总结了勘查方法技术组合;指出在Ⅰ、Ⅱ隐伏岩体分布区银(金)铅锌矿床的下部有寻找斑岩型钼、钨、铜矿产的潜力。

The Zhaiwa concealed rock mass is one of the eight concealed and semi-concealed rock masses inferred from the interpretation of gravity and magnetic data in southwestern Henan Province,with an area of 310 km^2. Major molybdenum( tungsten) lead-zinc-silver( gold) deposits in southwestern Henan are mainly distributed in these eight concealed and semi-concealed rock masses and their vicinity,indicative of very obvious spatial-temporal relationship between them. It is of great significance to study the distribution pattern,depth,occurrence and distribution of deep and large faults in concealed rock mass for guiding deep prospecting and exploration. By studying the variation characteristics and distribution regularity of gravity and magnetic field of the Zhaiwa concealed rock mass,and by related quantitative calculation,the intrusion model of the concealed rock mass was determined. This concealed rock mass in the whole area is divided into three areas as follows. The top depth of the concealed rock mass in the area Ⅰ is 0 ~ 0. 8 km,with a distribution area of about 71 km^2. The top depth of the concealed rock mass in the area Ⅱ is 0. 8 ~ 2 km,with an area of about 153 km^2. The top depth of the concealed rock mass in the area Ⅲ is 2 ~ 4 km,and the distribution area is about 86 km^2. Based on the intrusive model of concealed rock mass and the geophysical anomaly characteristics of typical deposits,a three-dimensional metallogenic model( transition model of metallogenic elements from shallow to deep,from low to medium temperature to high temperature) and a comprehensive geophysical prospecting model( geophysical anomaly markers including concealed rock mass,top zone of concealed rock mass,rock bell and porphyry rock mass,ore body( mineralization body)) were established. The exploration potential was predicted,and the technology portfolio of exploration methods was summarized. It is pointed out that there is potential for prospecting porphyry molybdenum,tungsten and copper ores in the lower part of Ag( Au) lead-zinc deposits in the distribution area of concealed rock masses Ⅰ and Ⅱ.