摘要
湖南前霞旦系冷家溪群和板溪群,主要由各种板岩,变质砂岩组成,夹有基性、中-酸性火山熔岩、火山沉积岩及碳酸盐岩。地层中Na_2O含量、Na_2O/K_2O及Co/Ni比值与其中火山沉积物的含量呈正相关关系。在平面上反映出存在几个火山物质沉积中心,黔阳至会同、沅陵至桃源之间及湘潭至双峰一带是板溪期火山物质沉积中心;平江至浏阳一带是冷家溪期火山物质沉积中心。湖南前震旦系金矿的分布几乎都集中在这些地区内。因此,Na_2O/K_2O,Co/Ni比值分布特征是金的区域成矿预测的地球化学标志。
The Presinian Lengjiaxi Group and Banxi Group in Hunan consist mainly of various kinds of slate and metamorphic sandstone, intercalated with tuffite, basic--intermediate acidic volcanic lava, pyroclastic sedimentary rocks and carbonate rocks.The Na_2O content,Na_2O/K_2O and Co/Ni ratios of the strata show positive correlation with the content of volcanic sediments. In the Na_2O/K_2O and Co/Ni isogram maps, several sedimentary centers of volcanic material are reflected.Qiangyang--Huitong, Yuanling--Taoyuan and Xiangtan--Shuangfeng were three volcanic sedimentary centers during Banxi Period; Pingjiang--Liuyang was a volcanic sedimentary center during Lengjiaxi Period.The distribution of presinian-hosted gold deposits in Hunan nearly centralized in these areas. Thus, the Na_2O/K_2O, Co/Ni ratios and their distribution can be regarded as a geochemical criterion in the regional metallogenic prognosis of gold.
出处
《湖南地质》
1991年第2期135-140,共6页
Hunan Geology
关键词
前震旦纪
火山岩
地球化学
金矿
Presinian
Volcanic sedimentary rock
Geochemistry
Gold deposit
