论文部分内容阅读
应用古火山地质学和岩石地球化学对白银厂中酸性火山穹隆内的凝灰岩、晶屑凝灰岩、中酸性枕状、绳状熔岩和具有特殊构造的补丁岩等火山碎屑岩进行了较为系统的研究 ,认为火山晶屑凝灰岩为酸性岩浆经爆发作用形成的火山碎屑流经细火山灰与富晶体碎屑部分分离后较快速度沉降并堆积成岩 ,产于火山喷口附近。海底成矿热液蚀变作用使其 Si O2 、Fe O、Mg O、CO2 等化学成分发生变化。凝灰质千枚岩则是细火山灰在海水中经缓慢的沉降后形成于远离火山口的火山斜坡上的火山 -沉积变质岩。根据“补丁”的成分可将补丁岩分为两种类型 :绿泥石质和火山凝灰质。其中绿泥石质补丁原为成矿热液在火山作用间歇期于喷流口附近因成矿蚀变作用所形成的薄厚不一的层状体或不规则体 ;凝灰质补丁的原始物质则是同时在火山口附近沉积的火山物质与海底沉积物之混合物 ,二者均被后期火山作用破碎并被其产物重新胶结而形成补丁岩。枕状角斑岩和“冻鱼状”角斑岩乃是同质岩浆在水深大于压力补偿深度条件下溢流相喷发产物 ,它的确定标志着对白银厂火山岩穹中火山作用认识上的进一步提高 ,也为建立白银矿田古火山机构、深入研究成矿作用提供了必要的基础。
The ancient volcanic geology and lithogeochemistry were systematically studied on volcaniclastic rocks such as tuff, crystal tuff, medium-acid pillow, rope lava and patch rock with special structure in the intermediate-acidic volcanic dome in Baiyin Plant , That the volcanic rock tuff tuff acidic acidic magma after the formation of volcanic debris flow through the fine volcanic ash and crystal-rich part of the debris separated faster settlement and accumulation of diagenesis, produced in the vicinity of volcanic vents. The hydrothermal alteration of seafloor mineralization changes the chemical composition of Si O2, Fe O, Mg O and CO2. Tuffitic phyllites are volcanic-sedimentary metamorphic rocks formed on the volcanic slope far away from the crater after slow volcanic ash has been subsided in seawater. Patch rock can be divided into two types based on the composition of the patch: chlorite and volcanic tuff. Among them, the chlorite patch was originally a superficial layer or irregular body formed by mineralization alteration in the intermittent period of volcanic mineralization in the intermittent volcanic period. The original material of tuffaceous patch Is a mixture of both volcanic and seabed sediments that are also deposited near the caldera, both of which were later broken up by volcanism and re-cemented by their products to form patch rock. Porphyry horn-shaped porphyry and “frozen fish-like” horn porphyry are the products of spillover facies eruption of homogeneous magma at water depth greater than the pressure compensation depth, and its determination marks further understanding of volcanic activity in the volcanic dome of the Baiyinchang Improve, but also for the establishment of the ancient volcano Baiyin ore bodies, in-depth study of mineralization provides the necessary foundation.