摘要
本文研究了湘西南漠滨地区元古界板溪群五强溪组地层中金的分布、微量元素地球化学及其与金的成矿关系,研究表明,本区五强溪组呈现明显的金亏损,而地层则具有富As、Sb,贫Hg、Sr,以及Co/Ni比值大于 1、Au/Ag及 Sr/Ba比值低的地球化学特点。金的分布在空间上有一定变化规律,从远离矿区的地层岩石到矿床内部的脉旁围岩,根据其丰度高低,相应地划分出背景区—亏损区—富集区—亏损区—富集区五个区段,后四者组成一个共轭体系。两次金亏损都是水热淋滤作用的结果,但二者在形成的时间、规模及地球化学特征上都存在显著差异。这种淋滤的阶段性,导致了漠滨金矿床的两期成矿作用。金以及其他成矿元素的亏损区或亏损带的出现有一定普通性,因而对找矿具有重要的指导意义。
Abstract
This paper studies the distribution of gold and the trace element geoche mistry related to gold metallization within Wuqiangxi Formation of Proterozoic Banxi Group in Mobin area, southwestern Hunan. Wuqiangxi Formation of this area is characterized geochemically by obvious depletion in Au, Hg and Sr and enrichment in As and Sb with Co/Ni>1 and Au/Ag and Sr/Ba very low. The spatial distribution of gold shows some regularity: from the distant strata to the wall rocks beside the ore vein within the ore deposit, five zones can be successively detected, i. e., background zone, depleted zone, enriched zone.deple-ted zone and enriched zone, with the last four zones forminga conjugate system. The two processes of gold depletion resulted from two separate hydrothermal leaching processes different from each other in time, scale and geochemical characteristics. Such multi-stage leaching led to two-phase metallization In the Mobin gold deposit. The appearance of the depleted areas or zones of gold and other ore-forming elements seems ubiquitous to some extent, thus serving as an important indicator in ore prospecting.
出处
《物探与化探》
CAS
CSCD
1992年第4期295-303,共9页
Geophysical and Geochemical Exploration
基金
国家自然科学基金资助项目
