摘要
区域地层为较稳定的沉积岩层,中二叠系梁山组含铝岩系广泛分布于区域上向斜构造内,为铝土矿的找矿奠定了物质基础.区内车盘向斜构造控制着铝土矿的分布,使探矿工作成为可能.由于铝土矿无明显的磁性、密度差异等物性特征,铝土矿的地球物理勘探仍然是盲区,单一的地球物理方法难以提取出其异常特征.本文阐述了综合利用音频大地电磁法(AMT)和直流电测深(DC)两种物探方法在沉积岩中查找铝土矿,并获得良好的效果.音频大地电磁测深法可以提供大尺度的岩性分布特征.直流电测深能准确的划分出地下介质层位的电阻率分布,且对细小异常的分辨能力强.据地质资料推测,目标矿层铝土矿位于石灰岩与砂泥岩分界面中.AMT能划分出分界面,但难以识别覆存其中的目标矿体,利用DC可查出该异常.结合钻孔资料可以验证异常,同时对比进行物探数据的处理和解释,这样的组合勘探方法对于深部找矿及后期的开发是行之有效的.
This region has a more stable sedimentary layer,the aluminum-containing rocks of Permian Liangshan group widely distributed in the area within a synclinal structure;therefore,it is the material foundation for seeking bauxite.Local Chepan synclinal controls the distribution of bauxite,so it is possible for us to do the prospecting work.Due to minor differences in physical characteristics,geophysical exploration for bauxite is still blind,single geophysical method is difficult to extract the abnormal characteristics.In this paper,utilize Audio Magnetotelluric method（AMT） and the electrical sounding（DC） to locate bauxite in sedimentary（The main lithology： Limestone and Sandstone）,and get good results.AMT can provide large-scale lithological distribution.DC can accurately divide the subsurface resistivity distribution layer,even can distinguish small anomaly.According to geological data speculation,the target seam located in the interface of limestone and shale.AMT can divide the interface,but can not identify the objectives in it;however DC can find the exception.Combine the borehole data,we can verify the anomaly,also compared to do geophysical data processing and interpretation,exploration of this combination method for deep probing and later development is effective.
出处
《地球物理学进展》
CSCD
北大核心
2012年第2期709-714,共6页
Progress in Geophysics
基金
中国地质调查局项目(1210011085167)资助
