航空重力局部异常地质成因分类及找矿意义

Geological-genetic Classification and Prospecting Significance on Local Anomaly of Airborne Gravimetry

以我国首次试验的航空重力数据为基础,通过局部重力异常的突出方法处理和反演拟合,结合航磁、地震、钻井等资料,按照引起局部异常的地质体性质,将研究区的局部重力异常划分为6类,即与基岩凸起有关的局部异常、与基岩凹陷有关的局部异常、与侵入岩有关的局部异常、与喷出岩有关的局部异常、与中酸性岩浆岩中老地层有关的局部异常、与深部地幔柱有关的局部异常。每类局部异常又可根据具体的地质体属性划分为若干种局部异常,并构成某种矿产资源的反映。其中,基岩凸起异常、基岩凹陷异常、岩浆岩体异常分别构成油气田、煤田、金属矿床的重要找矿标志。正确认识局部重力异常及其成因,是航空重力地质资源调查的目标之一,具有重要的找矿意义。

Based on the airborne gravimetric data of the first-time experimentation in China,passing through the emphasized processing and inverse simulation of local gravity anomalies and combining with the aeromagnetic,seismic and drilling data,according to the character of the geological body which cause the local anomaly,six types of local gravity anomalies are divided in this research area,which are associated respectively with basement salients,basement sags,intrusive rocks,volcanic rocks,old strata within intermediate-acid magmatic rocks and mantle plume in deep place,etc.Every type of local gravity anomalies can also be divided into some kinds of local anomalies according to the geological attribute,which can be the reflection of certain mineral resources.Among them,the local gravity anomalies about basement salients,basement sags and magmatic rocks respectively constitute the important prospecting symbols of oil and gas fields,coal fields and metal deposits.Identifying the local gravity anomalies and their genesis correctly is one of the aims about airborne gravimetry.