铜陵焦冲金矿岩浆作用过程:来自闪长玢岩的证据
发布时间：2018-10-24 20:10
【摘要】：本文主要针对安徽铜陵焦冲金矿区的闪长玢岩进行了详细的岩相学观察和矿物电子探针分析。岩相学观察表明,岩石内发育独特的石英斑晶、斜长石斑晶及其中的角闪石包裹体和角闪石斑晶。石英斑晶呈港湾状或次圆形,由溶蚀的次圆形内核和生长边构成,在内核与边部之间有熔融包裹体产出;斜长石斑晶具明显的"核-幔-边"环带结构,幔部发育明显的溶蚀界面,溶蚀界面处大量熔融包裹体呈环带分布;角闪石包裹体分别包裹于斜长石斑晶的核部和幔部,后者的边部被溶蚀呈次圆形;角闪石斑晶呈长条形,包裹有细针状的磷灰石。电子探针分析结果表明,斜长石中An含量自核部至边缘呈降低趋势,幔部出现多个An峰值;而来自斜长石斑晶核部、幔部和基质中的角闪石Al2O3含量从核部至基质也逐渐下降。采用角闪石-斜长石温压计和角闪石全铝压力计,分别对斜长石斑晶核部及包裹的角闪石、斜长石斑晶幔部及包裹的角闪石和基质中共生的角闪石-斜长石微晶的结晶温度和压力进行估计,结果表明,温度为806.84~808.75、791.00~797.86和660.3~683.9℃,压力为675~706、463~487和206~212 MPa,对应的形成深度为25.52~26.70、17.50~18.40和7.79~8.02km。角闪石斑晶的结晶压力和深度为448~483MPa和16.93~18.25km,与包裹于斜长石幔部的角闪石包裹体一致。根据以上岩相学和角闪石-斜长石矿物化学分析结果,本文提出一个多重岩浆房模型:来自深部幔源的流体(透岩浆流体)将不同层位的岩浆房串联活化,活化后的中基性岩浆和花岗闪长质岩浆混合形成中性岩浆,最后中性富流体的岩浆快速上侵冷却就位于地表,同时释放大量的挥发分(含矿物质),后期的减压排气作用可能是主要的成矿机制。
[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，
本文编号：2292424
[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，
本文编号：2292424
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