相山火山盆地磁性结构分布特征

以相山地区大比例尺重磁测量结果为基础,建立正演计算模型,采用模拟退火算法,反演计算了相山盆地不同深度下的物性结构分布特征,对该盆地地下岩层结构及界面变化趋势进行了半定量和定性分析;盆地深部构造岩浆活动发育,局部地段次火山岩体具向下延深和扩大的趋势;西北面磁性界面变化较复杂,磁性岩体的埋深均小于800 m;东南面磁性界面变化相对较平缓,磁性岩体的埋深均大于800 m;盆地中有多个岩浆通道,后期构造岩浆活动主要发生在盆地西南侧、南侧以及东侧,这可能是导致北西侧铀富集成矿好于这些部位的主要原因,受构造影响,盆地中部及西北部,磁性基底呈块状分布.这对指导相山的攻深找盲工作有重要意义.

The Characteristic Analysis of the Magnetic Structure Distribution in Xiangsan Volcanic Basin

Basing on large-scale gravity and magnetic surveying result in Xiangsan area, the forward modeling were established in this paper. By using simulate annealing algorithm, the physical construction distribution at different depth in Xiangsan volcanic basin were calculated and the underground structure of the rock layers and variation trend of the interface were analyzed. According to the calculation results, we think that the magma activity and deepther structure of the basin were development, the local sub volcanic rocks trended deeper underground and trended expansile, the variation of the interface were relatively complex at the northeast parts and the buried depth of the magnetic rocks were larger than 800 meters, the variation of the interface were relatively smooth at the southeast parts and the buried depth of the magnetic rocks were less than 800 meters. There were the muti-channels of the magma, the magma activity of the anaphase structure were development at the southeast or south and east parts of the Xiangsan basin. This is the main reason why at this parts the uranium deposit were enrichment and the uranium were controlled by structure and the magnetic rocks were massive body. There is of great significant for guiding to find deeper underground uranium in Xiangsan areas.