论文部分内容阅读
黑龙江省五大连池钾质火山岩石中普遍含有壳源捕虏体和捕虏晶,并多赋存于火山集块、浮岩砾、火山渣等各级火山碎屑物及盾状台地的表皮相到内部相火山熔岩中。花岗岩质捕虏体一般大小为5～50cm,捕虏晶一般为0.2～5mm,成分以二长花岗岩为主,少见花岗闪长岩及黑云母英云闪长岩和少量砂岩捕虏体。石英、斜长石、少数钾长石捕虏晶见于各期火山碎屑(物)和熔岩中,其中以石英捕虏晶最为常见。壳源捕虏体中的代表性矿物及浅色玻璃电子探针分析结果表明,火山岩SiO2偏高是岩浆上涌喷发过程中捕获了大量壳源物质的结果。五大连池火山群富钾火山岩岩石化学、地球化学长期保持均一,说明其岩浆直接来自EMⅠ型钾质地幔,岩浆在上升过程中遭受了地壳物质的明显混染。
The Wudalianchi potassic volcanic rocks in Heilongjiang Province generally contain crustal xenoliths and xenocrysts, and are mostly found in volcanic fragments, floating rock gravels, volcanic slag and other volcanoes at all levels and the epidermal phase of shield platform Internal volcano lava. The general size of the granite xenoliths is 5 ~ 50cm and the xenocrysts are generally 0.2 ~ 5mm. The composition is mainly of monzonitic granite, rare granodiorite and biotite diorite and a few of sandstone xenoliths. Quartz, plagioclase, a small number of potassium feldspar xenocryst found in various periods of volcanic debris (objects) and lava, of which the most common quartz xenolith. The analysis of representative minerals and light-colored glass electron probe in the xenoliths shows that the high SiO2 of volcanic rocks is the result of large amount of crustal material captured during the magmatic upwelling eruption. The petrochemistry and geochemistry of the volcanic rocks rich in volcanic rocks in the Wudalianchi volcano are consistent for a long period of time, indicating that their magmas are directly derived from the EMⅠ-type kali mantle and the magma suffered obvious contamination of the crustal material during the ascent.