铜陵东狮子山铜矿床地质特征及成岩成矿机理研究  

GEOLOGICAL CHARACTERISTICS AND ORE FORMING AND ROCK FORMING MECHANISM OF THE DONGSHIZISHAN COPPER DEPOSIT IN TONGLING, ANHUI PROVINCE

作　　者：凌其聪[1] 程惠兰 陈邦国 

机构地区：[1]中国地质大学

出　　处：《矿床地质》1998年第2期158-164,共7页Mineral Deposits

基　　金：国家自然科学基金

摘　　要：铜陵东狮子山铜矿为一夕卡岩矿床，但与常见的夕卡岩矿床明显不同。在产状方面，夕卡岩与围岩（大理岩）界线截然，围岩出现重结晶褪色边，夕卡岩边缘有淬火边，与夕卡岩相接触的辉石二长闪长岩出现烘烤褪色边，夕卡岩中出现辉石二长闪长岩角砾；在矿物组成上，具特殊的钾长石＋方解石＋石英囊状体，其内矿物边界规则，无分带现象，夕卡岩矿物无被交代现象；在结构构造方面出现特征的海绵陨铁结构、豆状构造、流动构造等；在地球化学方面，夕卡岩岩石的微量元素、稀土元素特征与辉石二长闪长岩相似，其中呈填隙状方解石的化学组成、同位素组成显示深源特征；夕卡岩矿物中出现熔融包裹体，均一温度高于９２０℃；矿体特征与寄主夕卡岩的各方面特征十分相似。这些特征显示该矿床可能是一种高温高密度粘稠的夕卡岩岩浆熔（流）体冷凝结晶演化过程的产物。The Dongshizishan copper deposit in Tongling is a skarn deposit which, unlike most of other skarn deposits, was not formed by metasomatism. The authors hold that the skarn and copper orebodies are products of a sort of sticky magmatic molten mass characterized by high temperature and density, as evidenced by a series of distinctive characteristics observed in the ore deposit. The boundary between the skarn and its country rock (marble) is clear and sharp, and the contact appears in embayed form with a recrystallization bleached zone on the side of the wall rock. The contact between the skarn and the pyroxene monzodiorite (another sort of wall rock) is also distinct, the former having a quenching zone and the latter possessing an optalic bleached zone. Besides, pyroxene monzodiorite rubbles can be seen in the skarn. All these typical phenomena are generally confined in magmatic rocks. As for the mineral association, a kind of unique “pegmatic pockets” composed of K feldspar, calcite and quartz can be seen in the skarn, with their boundaries being clear and regular. No metasomatism has been seen between these minerals and skarn minerals. Typical magmatic textures and structures, such as sideronitic texture, pisiform structure and flow structure are observed. Characteristics of trace elements and REE of skarn are similar to those of pyroxene monzodiorite. Chemical compositiion and δ 13 C , δ 18 O values of calcite among skarn minerals suggest that this mineral was derived from magma at depth. Moreover, molten inclusions occur in garnet of skarn with homogenization temperatures above 920℃. Orebodies and skarns are quite similar to each other in such aspects as mineral associations, textures and structures, trace elements and rare earth elements, suggesting that they were formed by the same process.

关 键 词：铜矿床 夕卡岩浆 成岩 成矿机理 矿床地质 

分 类 号：P618.410.2[天文地球—矿床学] P618.410.5[天文地球—地质学]