区域重磁圈定贵州基性-超基性隐伏岩体及地质意义

Basic-ultrabasic Hidden Rock Delineation of Guizhou by Regional Gravity Aaeromagnetic Survey Data and Its Geological Significance

贵州地表除峨眉山玄武岩外,其他岩浆岩出露不多。为了解深部的基性-超基性岩体隐伏情况及分布形态,本文结合地表该类岩体反映的地球物理场响应特征,利用区域重磁资料综合研究。在镇远马坪(钾镁煌斑岩)、贞丰鲁容-阴河(钙碱性煌斑岩)、罗甸沟亭-望谟大观(辉绿岩)、晴隆-织金西北(玄武岩)等岩浆岩出露区,与重磁场同位置相对应地区表现为重力高、磁力高分布特征,且重磁异常强度表现为高低不一的幅值变化。为保证将最小的隐伏岩体圈定,尽量消除区内岩浆岩受区域性剥蚀、风化的影响,故利用重力值2×10^-5m/s^2、磁力值10 nT为基准,联合圈定了省内百余处基性-超基性岩体分布,对寻找有关联的矿产指明了勘查方向。

In Guizhou province,Emeibasalt maily outcrop on the surface.In order to study the condition and distribution of basic-ultrabasic rockmass hidden condition,the regional gravity aaeromagnetic survey data are used for the comprehensible research with the geophysical response characteristics of this kind of rock on the surface.In Zhenyuan Maping(Kappa-magnesium porphyry),Zhenfeng Lurong-Yinhe(calcalkaline alum porphyry),Luodiangou Pavilion-Wangmo Daguan(diabase),Qinglong-Zhijin Northwest(Basalt and other magmatic rock outcrops,basalts and most other basic-ultrabasic rock outcrops seen on the surface are manifested as geophysical fields with high gravity,high magnetic force,and different anomalous amplitudes.In order to ensure that the smallest concealed rock mass is delineated,and the influence of regional erosion and weathering on magmatic rocks in the area is minimized,the gravity of 2×10^-5 m/s^ 2 and the magnetic force of 10 nT are used as the benchmark to jointly define the basicity of the province-The distribution of ultrabasic rocks indicates the direction of exploration for finding related minerals.