华南沉积岩系Hg、Sb丰度

摘要

从区域构造地球化学演化的角度来看,华南Hg、Sb矿床的形成主要可划分为三个阶段:(1)沉积层(主要是元古宙基底沉积层)堆积过程中Hg、Sb的储集；(2)元古宙基底(沉积层)的下沉-熔融-花岗岩形成与Hg、Sb释放；(3)在有利构造的引控下,含Hg、Sb流体形成、演化与成矿,简称为储存-释放-富集宏观三阶段.本文重点阐述的是第一阶段,华南沉积层特别是元古宙基底沉积层的Hg、Sb丰度.文中将华南沉积层H g、Sb丰度分为四种类型:Ⅰ原生本底丰度；Ⅱ同生异常丰度；Ⅲ后生丰度；Ⅳ混合丰度.本文计算、统计出华南沉积岩系本底丰度Hg为0.368 μg/g,Sb为1.28μg/g.华南元古宙基底沉积岩系本底丰度Hg为0.363μg/g,Sb为1.45 μg/g都明显高于地壳及花岗岩Hg、Sb丰度值.%The evolution of Hg-Sb provinces in South China can be divided into three stages: (1 ) pre-enrichment of ore metals in sedimentary sequences, especially in Proterozoic basement; (2) tectonically driven subsidence of the Proterozoic basement ( sedimentary sequences ) , followed by granite formation through partial melting of the basement; (3) involvement of structure-controlled fluids and subsequent ore mineral precipitation. This paper analyzes Hg and Sb abundances of sedimentary rocks ( the Proterozoic basement in particular) from South China. Four types of Hg-Sb abundances have been identified for the South China sedimentary rocks. They are primordial back-grouml abundance ( I ) , cogenetic abnormal abundance ( II ) , epigenetic abundance ( ID ) , and abundance being multiple in origin ( IV ). Average Hg and Sb background abundances are estimated to be 0. 368μ,g/g and 1. 28μg/g for the South China sedimentary strata and O.363μg/g and 1.45μg/g for the Proterozoic basement, respectively. These Hg-Sb abundance values are significantly higher than the average of the crust and granitic rocks.