湘西汞矿床的地质特征与成因

湘西汞矿床是湘黔汞矿带的重要组成部分.湘西汞矿受层位和构造双重控制,与岩浆活动没有直接联系,具有层带式整合矿体,矿物成分简单,汞锌矿化分带及后生成矿等地质特征.矿石硫来源于古海水硫酸盐的沉积硫;而汞的来源.则以上地幔去气作用产生的汞为主,寒武系等富汞建造的汞次之.燕山期地台活化时,以硫络合物或硫氢络合物的形式,在碱性溶液中沿深大断裂向上运转,当其与富含膏盐的客矿层相遇时,便与还原硫结合沉淀成矿.形成湘西层控后生汞矿床.

GEOLOGICAL CHARACTERISTICS OF MERCURY DEPOSITS AND ITS'''' METALLOGENY IN THE WESTERN HUNAN PROVINCE

Mercury deposits in the western Hunan Province make up an important part in the Hunan-Guizhou mercury ore belt. The mercury deposits in the western Hunan are controlled by both stratigraphic horizons and structures, showing no direct relationship with magmatic activities. And the deposits are characterized by bedded concordant orebodies with simple mineral composition, Hg-Zn ore zoning and epigenetic mineralization. Sulfur in ore was derived from sedimentary sulfates in paleo-sea water while the mercury was mainly originated from degassification in upper mantle , with the minority from the mercury-rich formation such as Cambrian System. During the platform activation process in Yanshanian period, sulfur removed upwords in the form of S-complcxcs and / or S-H complexes in alkaline solution along deep fractures. When it encountered with gypsum-rich ore-hosted layers, it would combine with reducing sulfur and deposit to form the stratabound epigenetic mercury deposits in western Hunan.