四川米易青皮村侵入体的固结过程

发布时间：2017-12-28 22:03

本文关键词：四川米易青皮村侵入体的固结过程　出处：《中国地质大学(北京)》2016年硕士论文　论文类型：学位论文

【摘要】：含矿与无矿侵入体的区分是阐明岩浆型矿床成因的基础,也是深部找矿预测的依据。本文选择四川米易青皮村岩体为例,通过岩相学及矿物成分剖面和定量化结构分析,试图阐明无矿岩浆侵入体的固结过程,并与攀枝花含矿岩体对比,进一步揭示含矿与无矿侵入体形成过程的区别。岩相学分析表明,青皮村岩体中粒辉长岩的造岩矿物可以划分为四个世代:(1)粗粒斜长石→(2)中粒斜长石+单斜辉石→(3)黑云母+铁钛氧化物→(4)伟晶状斜长石,展示了封闭系统的固结过程。加上粗晶辉长岩脉的矿物组合钠长石+单斜辉石+角闪石+磷灰石,可以将青皮村岩体的组成矿物划分为5个世代,进而划分成四个晶体群:通道晶体群、岩浆房晶体群、基质晶体群和流体晶体群。晶体成分剖面分析表明,通道晶和岩浆房晶显示正环带,具有封闭系统降温结晶的特点,其中通道晶的生长伴随着减压作用;基质晶初始为正环带,末期显示反环带,反映了残余流体的聚集与逃逸;而流体晶体群的产出则反映了超临界流体的相分离和排气作用。定量化结构分析揭示了岩浆固结晚期的粗化过程,是封闭岩浆系统固结过程的重要证据,与岩相学和晶体成分剖面分析结果一致。此外,青皮村岩体中Fe-Ti氧化物含量甚低,仅为4vol.%,暗示它们不可能聚集成矿。与攀枝花岩体相比,青皮村岩体固结过程中缺失先存晶体的溶蚀结构,后者被认为是高温含矿流体输入的结果。据此,本文提出,外来含矿流体(透岩浆流体)输入与否决定了镁铁质岩浆侵入体的产矿能力;进而认为,是流体输入导致了岩浆分异,而不是岩浆分异产生了含矿流体。
[Abstract]:The distinction between ore - bearing and ore - free intrusions is the basis for clarifying the genesis of magmatic deposits and also the basis for the prediction of deep ore prospecting. This paper chooses Sichuan Miyi green rock village as an example, the petrography and mineral composition profile and quantitative structure analysis, tries to clarify the consolidation process of ore magma, ore and rock in contrast to Panzhihua, further reveal the ore and non ore formation of the intrusion process area. Petrographic analysis showed that the Green Village rock grain gabbro rock forming minerals can be divided into four generations: (1) coarse plagioclase, (2) in the grains of plagioclase + clinopyroxene, biotite + (3), Wei Jingzhuang (4) Fe Ti oxide plagioclase, shows the consolidation process of closed system. With coarse grained gabbro vein minerals albite + clinopyroxene + hornblende + apatite mineral composition can be divided into 5 village green rock generation, and then divided into four groups: channel group, crystal crystal crystal crystal magma chamber group, matrix group and fluid crystal group. The crystal composition profile analysis shows that channel crystal and crystal display is zoned magma chamber, has the characteristics of closed system crystallization, which channel crystal growth with decompression effect; matrix crystal is the initial ring, end display reverse zoning, reflect the residual fluid accumulation and escape; and the fluid output reflects the crystal group the phase separation of supercritical fluid and exhaust effect. Quantitative structural analysis reveals the coarsening process at the late stage of magma consolidation, which is an important evidence for the consolidation process of closed magmatic system, and is consistent with petrography and crystal composition profile analysis. In addition, Fe-Ti oxide content in Rock Village peel is very low, only 4vol.%, suggesting that they may not accumulation. Compared with the Panzhihua rock mass, rock mass structure corrosion in the process of consolidation lack of village green to deposit crystals, and the latter is the result of the high temperature fluid containing ore input. Based on this, it is proposed that the ore bearing ability of mafic magma intrusive bodies is determined by the input of external ore bearing fluids (permeation magmatic fluid), and it is considered that fluid input leads to magmatic differentiation rather than magmatic differentiation, resulting in ore bearing fluids.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P611

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