安徽庐枞盆地中段重磁电特征及地质意义

安徽庐枞盆地是长江中下游成矿带的重要矿集区,其深部火山岩基底性质不明,制约了矿产勘探的开展。通过对庐枞火山岩盆地中段1∶5万高精度重磁数据及大地电磁测深数据进行再处理,探讨该区地球物理场的特征及其地质意义。结果表明: 庐枞火山岩盆地位于NE向古生代地层褶皱带的“鞍部”,火山岩厚度与重力剩余异常幅值变化具有较好的对应关系; 火山岩之下主体为隐伏侵入岩,呈似厚层状,底界面厚度为3~4 km,黄屯—枞阳断裂与罗河断裂是主要的深部岩浆通道。推断盆地内三叠系—石炭系主体被侵位,部分泥盆系—志留系在隐伏侵入岩之下发育。研究成果可为庐枞盆地基础地质研究及找矿预测提供参考。

Features and geological significance of gravity-magnetic-electric from the middle part of Lujiang—Zongyang basin in Anhui Province

Lujiang-Zongyang basin is an importatant ore concentration area in middle-lower reaches of Yang-tze, and the characteristics of volcanic basement were unclear, which had restricted the mineral exploration. Based on the reprocessing and understanding of 1∶50 000 high precision gravity-magnetic data and magnetotelluric measurement data in the research area, the researchers in this paper discussed the characteristics and geolo-gical significance of the geophysical field. The results show that the Lujiang-Zongyang volcanic basin is located in the saddle of the Paleozoic fold belt with NE trending, and the thickness of volcanic strata is related to the distribution of local gravity anomaly values. The hidden intrusive rock is under the volcanic strata, which is thick-bedded, with depth of bottom surface of 3~4 km. The Huangtun-Zongyang fault and the Luohe fault are the main tunnel for hypomagma. The Triassic-Carboniferous strata was intruded, and the Silurian-Devonian strata was developed under the hidden intrusive rock. This research provides important clues for the fundamental geology research and ore prospecting prediction in Lujiang-Zongyang volcanic basin.