中文摘要：

榍石是钙碱性花岗岩中常见的副矿物,因Ti4＋与Sn4＋具有相近的晶体化学性质,榍石可以有不同含量的Sn,因此,榍石是研究含锡花岗岩（特别是氧化型花岗岩）的有用矿物之一。本文选择南岭地区中段3个含锡花岗岩（骑田岭、花山、姑婆山）和3个尚未发现重要锡矿化的花岗岩（连阳、大东山、九峰）中的榍石进行了系统的矿物学研究。在这些花岗岩中,榍石都可以既形成于岩浆早期,也可以形成于黑云母绿泥石化的热液阶段。在骑田岭、花山和九峰花岗岩中,还发现了岩浆晚期结晶的榍石。电子探针分析结果表明,三类榍石具有不同的微量元素成分,岩浆早期榍石含有微量Sn（SnO2一般低于1%）,岩浆晚期榍石明显富锡,在不同花岗岩中ω（SnO2）可从约3%到26%不等,热液榍石则以富Al,F为特征。进一步对比6个花岗岩中榍石的化学成分发现,骑田岭、花山和姑婆山3个含锡花岗岩中的榍石（无论是岩浆阶段的,还是热液阶段的）都以富锡为特征（SnO2平均高于0.4%）,显示3个花岗岩具有较强的锡成矿能力;而在3个尚未发现重要锡矿的花岗岩中,连阳、大东山花岗岩中的榍石明显贫锡（SnO2含量低于0.1%）,但九峰花岗岩中的榍石与花山花岗岩中的榍石十分相似,岩浆榍石最高可含约3%SnO2,热液型榍石也可含2%的SnO2,预示九峰花岗岩可能具有较好的锡矿勘探前景。本文研究结果表明,榍石可以作为判别花岗岩锡成矿能力的简便、实用的矿物学标志。

英文摘要：

Titanite is a common accessory mineral in calc-alkailine granites,and may contain tin to various extents owing to similar crystal-chemical features between Ti 4＋ and Sn 4＋ .It thus may be considered as a useful mineral in studying tin granites（particularly oxidized tin granites） .This paper deals with a systematic study on titanite from three granites with known extensive tin mineralization（Qitianling,Huashan and Guposhan） and other three granites currently unknown for important tin mineralization（Lianyang,Dadongshan and Jiufeng） .Titanite from all these granites can form both at early-magmatic stage and during biotite chloritization at hydrothermal stage;late-magmatitc titanite is also found in Qitianling,Huashan and Jiufeng.Electron-microprobe results reveal distinct compositions among three types of titanite.Early-magmatic titanite contains trace of tin（generally1% SnO2） ,whereas late-magmatic titanite with 3 to 26%SnO2 can be found in Qitianling,Huashan and Jiufeng.Hydrothermal titanite is typified by high Al and F contents.Comparison of SnO2 contents for titanite from six granites shows that titanite,either magmatic or hydrothermal,from three tin granites（Qitianling,Huashan and Guposhan） is rich in SnO2 with averages0.4%,revealing their strong tin mineralizing potential;titanite of Lianyang and Dadongshan granites is very poor in SnO2（0.1%） ,consistent with their barren feature.However,similar to Huashan titanite,the magmatic titanite from Jiufeng granite contains up to 3%SnO2,and hydrothermal one up to 2%SnO2.Such tin enrichment in titanite might imply higher tin potential of the Jiufeng granite,possibly favorable for further tin exploration.The present results demonstrate that titanite may act as a simple,but useful mineral criterion of tin mineralizing potential in granites.