【摘要】：本文主要針對(duì)安徽銅陵焦沖金礦區(qū)的閃長(zhǎng)玢巖進(jìn)行了詳細(xì)的巖相學(xué)觀察和礦物電子探針?lè)治�。巖相學(xué)觀察表明,巖石內(nèi)發(fā)育獨(dú)特的石英斑晶、斜長(zhǎng)石斑晶及其中的角閃石包裹體和角閃石斑晶。石英斑晶呈港灣狀或次圓形,由溶蝕的次圓形內(nèi)核和生長(zhǎng)邊構(gòu)成,在內(nèi)核與邊部之間有熔融包裹體產(chǎn)出;斜長(zhǎng)石斑晶具明顯的"核-幔-邊"環(huán)帶結(jié)構(gòu),幔部發(fā)育明顯的溶蝕界面,溶蝕界面處大量熔融包裹體呈環(huán)帶分布;角閃石包裹體分別包裹于斜長(zhǎng)石斑晶的核部和幔部,后者的邊部被溶蝕呈次圓形;角閃石斑晶呈長(zhǎng)條形,包裹有細(xì)針狀的磷灰石。電子探針?lè)治鼋Y(jié)果表明,斜長(zhǎng)石中An含量自核部至邊緣呈降低趨勢(shì),幔部出現(xiàn)多個(gè)An峰值;而來(lái)自斜長(zhǎng)石斑晶核部、幔部和基質(zhì)中的角閃石Al2O3含量從核部至基質(zhì)也逐漸下降。采用角閃石-斜長(zhǎng)石溫壓計(jì)和角閃石全鋁壓力計(jì),分別對(duì)斜長(zhǎng)石斑晶核部及包裹的角閃石、斜長(zhǎng)石斑晶幔部及包裹的角閃石和基質(zhì)中共生的角閃石-斜長(zhǎng)石微晶的結(jié)晶溫度和壓力進(jìn)行估計(jì),結(jié)果表明,溫度為806.84~808.75、791.00~797.86和660.3~683.9℃,壓力為675~706、463~487和206~212 MPa,對(duì)應(yīng)的形成深度為25.52~26.70、17.50~18.40和7.79~8.02km。角閃石斑晶的結(jié)晶壓力和深度為448~483MPa和16.93~18.25km,與包裹于斜長(zhǎng)石幔部的角閃石包裹體一致。根據(jù)以上巖相學(xué)和角閃石-斜長(zhǎng)石礦物化學(xué)分析結(jié)果,本文提出一個(gè)多重巖漿房模型:來(lái)自深部幔源的流體(透巖漿流體)將不同層位的巖漿房串聯(lián)活化,活化后的中基性巖漿和花崗閃長(zhǎng)質(zhì)巖漿混合形成中性巖漿,最后中性富流體的巖漿快速上侵冷卻就位于地表,同時(shí)釋放大量的揮發(fā)分(含礦物質(zhì)),后期的減壓排氣作用可能是主要的成礦機(jī)制。
[Abstract]:In this paper, the detailed petrographic observation and electron microprobe analysis of diorite porphyrite in Jiaochong gold deposit area, Tongling, Anhui Province have been carried out. The petrographic observation shows that the quartz porphyry, plagioclase porphyry and its hornblende inclusions and hornblende porphyries are developed in the rocks. Quartz porphyry, which is composed of dissolved subcircular core and growth edge, has a melt inclusion between the core and the edge, and plagioclase porphyry has a distinct "core-mantle-edge" ring structure. There are obvious dissolution interfaces developed in the mantle, a large number of melt inclusions are distributed in a circular zone at the dissolution interface, the hornblende inclusions are wrapped in the core and the mantle part of the plagioclase porphyry, respectively, the edge of the latter is dissolved in a subcircular form, and the amphibole porphyry appears as a long stripe. Wrapped in fine needle-shaped apatite. The results of electron microprobe analysis show that the An content in plagioclase decreases from the core to the edge, and there are several An peaks in the mantle, while from the plagioclase core, the Al2O3 content of the amphibole in the mantle and matrix decreases gradually from the core to the matrix. Using hornblende plagioclase temperature and pressure gauge and hornblende all aluminum pressure gauge, the kernels of plagioclase spot and the carnblende wrapped in it are respectively analyzed. The crystallization temperature and pressure of amphibole and amphibolite-plagioclase microcrystals are estimated. The results show that the temperatures are 806.84 / 808.75791.0077.86 and 660.3683.9 鈩，

本文編號(hào)：2292424