利用宽谱系岩墙群进行靶区定位的数值方法——以新疆南阿拉套山为例  

A quantitative method for target prediction using the wide composition-spectrum dike swarms: A case study of the South Alataw Mountain in Xinjiang

作　　者：郭晶[1] 罗照华[1] 刘晓[1] 姜会营[1] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,北京100083

出　　处：《中国地质》2013年第2期423-429,共7页Geology in China

基　　金：中国地质调查局地质调查工作项目(1212011220921);科技部国际科技合作项目(2010DFB23390)资助

摘　　要：本文介绍一种利用宽谱系岩墙群的空间展布特征进行靶区定位的数值方法。基于透岩浆流体成矿理论,岩浆-屏蔽层强相互作用过程中将涌现最大主压应力分布在竖直方向的近场应力场。在这种条件下,屏蔽层中的裂隙系统不同于传统矿田构造学描述的裂隙系统。依岩浆上升速率及屏蔽层岩石学结构和力学性质变化,屏蔽层中可出现不同类型的同成矿裂隙系统,后者往往被成矿期的脉岩充填。由于应力中心的作用力强度大于远离应力中心的部位,自生长裂隙和先存裂隙的密度呈现规律性的空间变化。这种变化控制了含矿流体的运动学特征。因此,可以将岩墙密度和延伸方向数作为定量化指标揭示含矿流体大规模聚集的空间位置,后者也是成矿作用的潜在发生部位。用滑动平均法绘制岩墙分布密度图和岩墙延伸方向密度图,将极密区作为有利找矿靶区,分析结果与地质学方法的预测结果高度相似。因此,可以认为本文提供的靶区圈定方法是一种简便有效的方法。A numerical method is presented for spatial targeting by parametrizing distribution of the wide composition-spectrum dike swarms （WSDS）. According to the metallogenic theory on the transmagmatic fluids, the local stress field with a vertical maximum principle stress axis emerges when violent interaction between the magma body and the shielding layer takes place. Consequently the corresponding fissure system differs from the fissure system described in the traditional structural geology of orefield. In accordance with a variety of ascending rates of magma and textural and mechanical properties of the shielding layer, there would be several types of syn- metaUogenic fissure subsystems, in which veins of metaUogenic period usually fill. Because the strength of effort at the center is much stronger than that at the surrounding places, the pre-existent and the self-propagated fractures show regular spatial patterns both in density of dikes and their stretching density and in direction, which determine the kinematics of fluids. So the directions can be considered as quantitative indexes to target the potential locations in which ore-bearing fluids are extensively cumulated, and mineralization occurs. Using moving- average method to get the contours of the dike densities and the dike stretching directions, the authors regard the maximums as the prediction targets. The result is highly consistent with that analyzed by the geological method. Therefore the quantitative method offered in this paper is effective.

关 键 词：岩墙分布密度图 岩墙延伸方向密度图 定量圈定 滑动平均法 透岩浆流体 

分 类 号：P612[天文地球—矿床学]