摘要
通过对铜陵地区系统的填图观察和室内研究 ,初步确定了铜陵地区海西期的热水沉积岩。它们是 :石炭系黄龙组 ,由下而上、由内到外的层序包括含硫化物滑石蛇纹石岩 (由原岩为含水富镁碳酸盐岩 +二氧化硅的热水沉积岩变质而成 )→块状、层状 (含铜金 )黄铁矿±铁碧玉±硬石膏±菱铁矿±菱锰矿±硅质岩→含炭质粘土→白云岩 ;二叠系为栖霞组 (含铅锌金 )硅质岩、孤峰组 (含锰 )硅质岩和大隆组 (含钼 )硅质岩。这些热水沉积岩总体构成铜陵地区晚古生代多期热水活动的格局。常量元素、微量元素和稀土元素的分析结果表明 ,本区的硅质岩具有热水沉积岩的特征。氧同位素估算的热水硅质岩古温度在 4 9℃以上。铜陵地区的热水沉积岩对层控矿床的勘查和隐伏矿床的预测评价具有重要的理论和实际意义 ,尤其是黄龙组底部的热水沉积岩是铜陵地区找矿的重要标志 ,对于指导长江中下游地区 ,如宁芜等地 ,寻找该层位的矿床有着不可替代的指示意义。
Based on the observation and research work conducted during mapping of Tongling district, the authors have determined the Hercynian hydrothermal sedimentary rocks. They include two sequences of rock, i.e., (1) the sequences of Upper Carboniferous Huanglong Formation, which upward or outward comprises laminated sulfide_bearing talc_serpentinite metamorphosed from a protolith, aquiferous magnesium_rich carbonates plus silica, massive, stratified copper_gold_bearing pyrite, and/or jasparite, anhydrite, siderite, rhodochrosite, silica, carbon_bearing clays and dolomite; (2) the sequences of Permian, Qixia Formation (P 1 q ) lead, zinc_bearing cherts, Gufeng Formation (P 1 g ) manganese_bearing chert, and Dalong Formation (P 2 d ) molybdenum_bearing chert. On the whole, these hydrothermal sedimentary rocks have characteristics of periodical hydrothermal activity in Late Paleozoic. Major, trace, and rare earth elements data of the cherts indicate that the cherts in Tongling district are characterized by exhalites or hydrothermal sedimentary rocks. Paleotemperature of cherts estimated by O isotope is over 49℃. In Tongling district, the hydrothermal sedimentary rocks are of great importance both in theory or practice for exploration of the stratabound deposits and in diagnosis of the hidden deposits. The exhalites at the bottom of the Huanglong Formation not only serve as an important indicator bed for exploration in Tongling district, but also play an irreplaceable role in guiding prospecting work in such areas of the middle_lower Yangtze valley as Ning_Wu (Nanjing_Wuhu) basin.
出处
《矿床地质》
CAS
CSCD
北大核心
2004年第3期334-343,共10页
Mineral Deposits
基金
国土资源部科技司专项研究计划 (编号 :B0 0 0 2_3 )
地质调查项目 (编号 :2 0 0 10 0 0 0 0 0 4)资助
关键词
地球化学
热水沉积岩
块状硫化物矿床
铜陵
geochemistry, Tongling, hydrothermal sedimentary rocks, exhalites, pyritic Sedex_type massive sulfide deposit
