本文關(guān)鍵詞：四川米易青皮村侵入體的固結(jié)過程　出處：《中國地質(zhì)大學(xué)(北京)》2016年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 攀枝花式鐵礦 巖漿分異 晶體群 定量化結(jié)構(gòu)分析 透巖漿流體

【摘要】：含礦與無礦侵入體的區(qū)分是闡明巖漿型礦床成因的基礎(chǔ),也是深部找礦預(yù)測的依據(jù)。本文選擇四川米易青皮村巖體為例,通過巖相學(xué)及礦物成分剖面和定量化結(jié)構(gòu)分析,試圖闡明無礦巖漿侵入體的固結(jié)過程,并與攀枝花含礦巖體對比,進(jìn)一步揭示含礦與無礦侵入體形成過程的區(qū)別。巖相學(xué)分析表明,青皮村巖體中粒輝長巖的造巖礦物可以劃分為四個世代:(1)粗粒斜長石→(2)中粒斜長石+單斜輝石→(3)黑云母+鐵鈦氧化物→(4)偉晶狀斜長石,展示了封閉系統(tǒng)的固結(jié)過程。加上粗晶輝長巖脈的礦物組合鈉長石+單斜輝石+角閃石+磷灰石,可以將青皮村巖體的組成礦物劃分為5個世代,進(jìn)而劃分成四個晶體群:通道晶體群、巖漿房晶體群、基質(zhì)晶體群和流體晶體群。晶體成分剖面分析表明,通道晶和巖漿房晶顯示正環(huán)帶,具有封閉系統(tǒng)降溫結(jié)晶的特點(diǎn),其中通道晶的生長伴隨著減壓作用;基質(zhì)晶初始為正環(huán)帶,末期顯示反環(huán)帶,反映了殘余流體的聚集與逃逸;而流體晶體群的產(chǎn)出則反映了超臨界流體的相分離和排氣作用。定量化結(jié)構(gòu)分析揭示了巖漿固結(jié)晚期的粗化過程,是封閉巖漿系統(tǒng)固結(jié)過程的重要證據(jù),與巖相學(xué)和晶體成分剖面分析結(jié)果一致。此外,青皮村巖體中Fe-Ti氧化物含量甚低,僅為4vol.%,暗示它們不可能聚集成礦。與攀枝花巖體相比,青皮村巖體固結(jié)過程中缺失先存晶體的溶蝕結(jié)構(gòu),后者被認(rèn)為是高溫含礦流體輸入的結(jié)果。據(jù)此,本文提出,外來含礦流體(透巖漿流體)輸入與否決定了鎂鐵質(zhì)巖漿侵入體的產(chǎn)礦能力;進(jìn)而認(rèn)為,是流體輸入導(dǎo)致了巖漿分異,而不是巖漿分異產(chǎn)生了含礦流體。
[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.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：P611

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