摘要
南秧田白钨矿矿床是我国西南地区一个罕见的超大型白钨矿矿床,矿体赋存在矽卡岩中,呈层状产出。层状矽卡岩矿物为辉石、石榴子石及少量符山石,退化蚀变矿物为绿帘石、绿泥石、透闪石、阳起石、磷灰石等。电子探针分析结果表明,矽卡岩矿物中的单斜辉石以次透辉石、似次透辉石、普通辉石为主,其次为低铁次透辉石,含极少量的透辉石;石榴子石端元组分以钙铝榴石为主,伴少量铁铝榴石和镁铝榴石;角闪石族矿物属单斜角闪石中的透闪石-阳起石类质同像系列。在矽卡岩中还有与电气石、红帘石等变质矿物。典型矿床对比研究表明,该矿床中矽卡岩的成分特征与传统岩浆交代钙质岩石形成的矽卡岩有明显差别,与澳大利亚Broken Hill Ettlewood热水沉积的钙硅酸盐的特征十分相似,暗示成矿作用可能与本区中-新元古代裂谷环境下的热泉活动相关。
Nanyangtian sheelite deposite is a rare giant sheelite deposite in southwestern China.The stratiform ore body was hosted in skarn.The main Skarn minerals are pyroxene,garnet and minor vesuvianite.The altered minerals are chlorite,hornblende,epidote,actinolite,apatite etc.The result of chemical composition obtained by electron probe analysis demostrated that clinopyxene is composed of（1） major sahlite,sahlite-alike and augite,minor ferrosalite and tiny diopside,（2） garnet majorly consists of grossularite,minor almandine and pyrope,（3）hornblende is tremolite-actinolite isomorphic series.Some metamorphic minerals,such as tourmaline and piedmontite,also occur in skarn rock.Compared with typical sheelite deposites,it is demonstrated that the compostion of skarn in Nanyangtian sheelite deposite is obviously different from traditional magmatic metasomatism skarn,but is very similar to that of Broken Hill Ettlewood sheelite deposite of Astrinia which derived from calc-silicate rocks precipitated in hot water.It is indicated that the mineralization of Nanyangtian sheelite deposite possibly is related to the hot spring from mesoproterozoic and neoproterozoic rift valley.
出处
《岩矿测试》
CAS
CSCD
北大核心
2011年第3期269-275,共7页
Rock and Mineral Analysis
基金
中国地质调查局地质调查项目资助(1212010880402)
中国地质调查局科研项目资助(1212010911065)
关键词
南秧田
白钨矿矿床
矽卡岩
矿物学特征
成因
Nanyangtian sheelite deposite
skarn
mineralogical features
genesis
