初论兰坪盆地构造流体与成矿作用的时空格架及可能的成矿模式  

A PRELIMINARY STUDY ON THE SPATIAL－TEMPORAL FRAMEWORK OF TECTONO－FLUIDS AND METALLOGENIC PROCESSES AND POSSIBLE METALLOGENIC MODEL IN THE LANPING BASIN

作　　者：李小明[1] 胡宝清[1] 

机构地区：[1]中国科学院长沙大地构造研究所,湖南长沙410013

出　　处：《大地构造与成矿学》2001年第2期187-193,共7页Geotectonica et Metallogenia

摘　　要：滇西兰坪盆地中新生代形成了丰富的金属与盐类矿床，是我国著名的热液矿床成矿带。成矿系统时─空结构的统一性是进行成矿规律研究和成矿预测的前提和指导思想，综合分析兰坪盆地的成矿时代、矿床的空间分布及区域地质背景，初步认为：晚白垩世至早第三纪，盆地西缘出现以铜为主的成矿作用；兰坪盆地主要成矿作用发生在早、晚第三纪期间，因盆地东、西部边界向两边地块的俯冲碰撞及中轴断裂带的强烈活动，导致盆地中央地带出现大规模成矿流体活动，成矿流体因物理化学性质的改变而发生分异、运移，及盆地受挤压隆升，变成山间盆地，出现不同类型、不同大小的流体圈闭，因而形成不同种类，不同规模的矿床；同时，含有挥发性组分汞、锑、砷的流体从深部沿中轴断裂带上升向两侧的次级构造裂隙带扩散，导致盆地东部复式背斜带中出现锑、汞、砷的成矿作用；其后，矿床受到改造和氧化作用。盆地内发育深大断裂；兰坪盆地的成矿作用是在构造流体演化的制约下完成的，同时成矿作用的发生改变了流体的性质和构造环境，促使流体的再次循环，出现成矿作用的多期性、分带性。Abundant metal and salt deposits emerged in the Lanping Basin,western Yunnan province in the Meso－Cenozoic,which is a famous hydrothermal ore deposits belt in China.The unity of metallogenic spatial－temporal structure is a prerequisite and guiding ideology for studying metallogenic law and forecast.The paper synthesizes metallogenic epochs,spatial distribution of ore deposits and regional geological background,to give preliminary views as follows:(1)from the late Cretaceous to the Paleogene,metallogenic processes,such as copper deposits,occurred at the western edge of the basin;(2) major metallogenic processes occurred between the Paleogene and the Neogene,because the eastern and western edges subducted into and collided with bilateral continental blocks, and activity of the central axis fault was strong,which led to the large scale metallogenic fluids action,and metallogenic fluids were separated and transportated because of changing physical and chemical nature.Squeezed and uplifted,the Lanping basin became an intermontane basin to contain many kinds of fluid traps,different kinds of ore deposits with different scales.Simultaneously,fluids with volatile elements Hg,Sb and As rising along the central axis fault diffused into subordinate fractures,which led to Hg,Sb and As metallogenic process in the eastern compound anticline;(3)and later, ore deposits have suffered reformation and oxidization.Deep and large faults flourished in the basin, metallogenic processes were restricted to tectono－fluids evolution in the Lanping Basin, Simultaneously,occurrence of metallogenic processes changed nature of fluid and structural environment,which led to fluid recycle,multi－stages and zonation of metallogenic processes.

关 键 词：构造流体 成矿作用 成矿时空格架 成矿模式 兰坪盆地 空间分布 成矿时代 

分 类 号：P611[天文地球—矿床学] P54[天文地球—地质学]