【作者】 马楠；

【导师】 邓军；

【作者基本信息】 中国地质大学（北京） ， 矿物学、岩石学、矿床学， 2014， 博士

【摘要】 在前人研究工作的基础上，本次工作主要针对腾冲锡矿带锡多金属矿床相关的岩浆岩，通过野外地质观察、室内镜下观察、岩石地球化学分析、同位素年代学研究等方法，对研究区早白垩世、晚白垩世和古近纪三期成矿、非成矿花岗岩进行岩石学、地球化学、岩石成因和地球动力学背景研究。然后结合典型矿床的野外地质、流体特征以及成矿年代学研究成果，探讨腾冲锡矿带形成原因。对腾冲锡矿带与锡多金属成矿有关的岩浆岩进行了全岩主微量元素、稀土元素以及锆石年代学、微量元素和Hf同位素地球化学研究。结果表明，腾冲锡矿带与锡多金属成矿有关的岩浆岩的结晶时代可以划分为三期，与区域花岗岩年代分期相对应：（1）早白垩世花岗岩，锆石LA-ICP-MS U-Pb年龄集中在123~122Ma之间；（2）晚白垩世花岗岩，锆石LA-ICP-MS U-Pb年龄集中在75~70Ma之间；（3）古近纪花岗岩，锆石LA-ICP-MS U-Pb年龄集中在62~50Ma之间，但在来利山出露更年轻的45Ma岩体。地球化学研究表明，腾冲锡多金属有关的岩体虽形成时代不同，但具有相似的岩石地球化学特征，但是早白垩世与其后两期花岗岩略有分别，而晚白垩世和古近纪两期花岗岩相似度较高。三期与锡多金属成矿有关的岩体均为高分异I型花岗岩，只是在演化过程中经历了不同程度的分异结晶作用和流体-熔体相互作用，且年龄约年轻、含矿性越好呈现分异作用、流体作用越强烈的大致趋势。Sr-Nd-Hf同位素结果显示，三期岩体原岩主要为火成岩质地壳发生部分熔融而形成，但是地幔物质的加入随着年龄的减轻逐渐增多。综合上述研究表明，研究区在早白垩世、晚白垩世和古近纪分别，在不同的大地构造背景下，经历类似的成岩过程，形成该区大规模岩浆岩分布。本文以滇滩铁（锡）矿床、大松坡锡矿床和来利山锡矿床为对象研究表明，在腾冲锡多金属成矿带中，虽形成不同矿种、不同类型的矿床，但其矿床地质、流体等特征均与典型的与花岗岩相关的岩浆热液矿床相近。此外，锡石LA-ICP-MC-MS U-Pb测年方法均表明，锡矿石的形成年龄与矿区内岩浆岩时代在误差范围内一致，即腾冲锡矿带锡矿化作用均分别发生于早白垩世、晚白垩世和古近纪，且为锡矿化为岩浆热液成因，热液演化活动较短。更多还原

【Abstract】 Aiming to studying on the igneous rocks related with the multi-metal deposits inthe Tengchong tin belt based on the previous research work, the author in this paperconducted the rounded research on the field observation, microscopic studies,petrologic geochemistry, geochronology etc. and the successive Lower Cretaceous,Upper Cretaceous and Paleogene metallogenesis, and also the research ofpetrology, geochemistry, petrogenesis, and the geodynamic settings of thenon-metallogenetic granite. Besides, the author discussed the genesis of theTengchong tin belt based on the field geology of typical deposits, fluid inclusions andthe data of ore-forming geochronology.From the data of the whole-rock major and trace elements of the igneous rocksassociated with the tin belt, and the studies of tin multi-metal metallogenesis, REEand zircon dating and Hf isotope geochemistry, the author identified three crystallizedepochs of the igneous rocks related with the Tengchong tin belt, which iscorresponding with the regional granite dating periods.1) Lower Cretaceous granite,aging from123to122Ma.2) Upper Cretaceous granite, ranging from75to70Ma.3)Paleogene granite, spanning from62to50Ma, while exposed a younger age in theLailishan,45Ma. All the data are based on the zircon U-Pb dating measured byLA-ICP-MS technique.Based on the geochemical studies, the rock mass associatedwith the Thengchong tin multi-metals share similar petrologic chemicalcharacteristics, even though formed at different dates. While, there is a smalldiscrepancy between the Lower Cretaceous granite and the late two epochs of granites,and the latter two ones have a higher similarity.All of the three epochs of the granitesbelong to the I-type granite. It’s just that they experienced different degree offractional crystallization and fluid-melt interaction, and the younger of the granite, thedegree of mineralization, differentiation and water-rock interaction. The outcome ofSr-Nd-Hf isotopes indicate that three epochs of the granites origin from the partialmelting of the igneous crust, however, the adding amount of the mantle materialsbegin to increase with the decline of their ages. From all the evidences above, at Lower Cretaceous, Upper Cretaceous and Paleogene epoch the research areasexperienced similar diagenetic process, and formed the large scale distribution of theigneous rocks, while at different tectonic settings.In this paper, Diantan iron (Sn) deposit, Dasongpo tin deposits, Lailishan tindeposit are our research objects. Based on the geology feature, fluid geochemistry andgeochronology study, we carried out a certain result. Research shows that inTengchong tin polymetallic mineralization belt, the deposits share the samegenesis,which is typical granite-related magmatic hydrothermal deposits. In addition,cassiterite LA-ICP-MC-MS U-Pb dating methods show that the ore-formation age ofthose tin deposits consistent with magmatic rocks within the error range, namely therole of Tengchong tin with tin mineralization occurred at both Early Cretaceous, LateCretaceous and Paleogene, and for the tin into magmatic hydrothermal origin,evolution of hydrothermal activity is shorter.更多还原