接触交代型铜矿床硫同位素地球化学研究

A geochemical study on sulfur isotope of contact metasomatism type copper deposits

我国接触交代型铜矿床主要集中在长江中下游和燕辽等成矿带；主要矿体产于浅成或超浅成中酸性侵入岩与碳酸盐岩接触带。主要矿物组合为黄铜矿、黄铁矿、磁铁矿、赤铁矿（少数矿床可见）、磁黄铁矿（少数矿床未见）、宽铜矿、钙铁榴石、透闪石、石英和方解石。矿床硫化物的硫同位素组成主要显示出两种特征，一种是单个矿床硫同位素组成变化范围大，变化范围在5‰～10‰，又有较大正值出现（如马鞍山、铜录山、铁山、个旧卡房和冬瓜山等矿床）；另一种单个矿床硫同位素组成变化范围小，一般不超过5‰，具有小的正值特点（如索尔库都克、武山、铜官山、城门山、赛什塘、七宝山等矿床）。根据硫同住素组成特征可以获得索尔库都克、武山、铜官山、城门山、赛什塘、七宝山等矿床的硫来自单一岩浆来源；马鞍山、铜录山、铁山、卡房和冬瓜山等矿床的硫来自于岩浆与围岩膏盐层混合来源。

Contact metasomatism type copper deposits in China are mainly distributed in the metallogenic belts in the middle and lower reaches of Changjiang River and Yanliao area, and main orebodies occur in the contact zone of hypabyssal or ultra-hypabyssal intermediate acidity intrusive rocks and carbonate rocks. The main mineral composition includes chalcopyrite, pyrite, magnetite, hematite （found in a few deposits）, pyrrhotite （unseen in a few deposits）, bornite, andradite, tremolite, quartz and calcite. Sulfur isotopic composition in sulfides of the deposits mainly have two features, one feature is that the variation range of sulfur isotope of single deposit is large which is from 5‰ to 10‰, with relatively high positive values appeared （in deposits such as Maanshan, Tonglushan, Tieshan, Gejiu-Kafang and Dongguashan）; the other feature is that the variation range of sulfur isotope of single deposit is small which is less than 5‰, with low positive values appeared （in deposits such as Suoerkuduke, Wushan, Tongguanshan, Chengmenshan, Saishitang, Qibaoshan）. Based on the features of sulfur isotope composition, the paper proposed that the sulfur of deposits such as Suoerkuduke, Wushan, Tongguanshan, Chengmenshan, Saishitang, Qibaoshan were from single source of magma; the sulfur of deposits such as Maanshan, Tonglushan, Tieshan, Gejiu-Kafang and Dongguashan were from mixed sources of magma and wall rock gypsum-salt layer.