华南某大型铀矿床成因新识  

A NEW GENETIC UNDERSTANDING FOR A HIGH-TONNAGE URANIUM DEPOSIT IN SOUTH CHINA

作　　者：闵茂中[1] 王湘云[1] 沈保培 文光斗 樊涛 

机构地区：[1]南京大学地球科学系,核工业中南303大队

出　　处：《大地构造与成矿学》1995年第2期155-160,共6页Geotectonica et Metallogenia

基　　金：国家教委博士点基金;贵阳地化所矿床地球化学开放实验室基金

摘　　要：华南某大型铀矿床具典型的岩溶特征。研究发现矿石中铀主要以微脉浸染状沥青铀矿形式存在，沥青铀矿的晶胞参数ａ０＝５．４１６～５．４２８，含氧系数为２．３１～２．３４，属低、中温热液成因。矿床中出现一套低、中温热液矿物组合。测得成矿温度为１５０～１８１℃（均一法）。矿床中热水叠加改造特征明显，故建议称之为岩溶热造铀矿床，是一种特殊的新成矿类型。The Bentou uranium deposit in Hunan Province of South China is a high-tonnage,high-grade and shallow depth ore body. The host rocks include limestones of the early Carboniferous Shidengzi Formation,which are overlain by shales and sandstones of early Carwere schistoided and mylonitized. Mineralizing ages are 135, 119 and 65 m. y. . On the basis of fluid inclusion data, hydrothermal fluids had temperatures of 150～181℃. Uranium was deposited as microveinet-disseminated pitchblende with unit cell parameter a of 5.416～5. 428 and oxidation coefficient of 2. 31～2. 34, indicating its low-intermediate temperature hydrothermal genesis. Antimonselite, violarite, ullmannite, niccolite and nickel-pyrite are the principal hydrothermal minerals in the deposit. Carbon, oxygen, sulfer and lead isotopic analyses of the ores and the host rocks suggest that hydrothermal system of Bentou deposit was by meteoric fluids and mineralizing matter derived from the host rocks. Therefore, authors may suppose that the Indosinian paleokarst facilitated uranium enrichment in the paleokarst system. Then, uraniumbearing underground water heated by the Yanshanian and the Himalayan tectonic movements transformed and superimposed the uranium-bearing paleokarst sediment. As a result, Bentou uranium deposit, called paleokarst hydrothermal superimposition and transformation type deposit,was formed. Mixing of uranium-bearing warm tectonic water with cool paleokarst water may play an important role in deposition of mineralizing matter.

关 键 词：铀矿床 古岩溶 成因 热水成矿 

分 类 号：P619.140.1[天文地球—矿床学]