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通过大量的岩心观察,结合薄片鉴定、扫描电镜等资料,开展了准噶尔盆地西北缘火山岩溶蚀孔隙特征及成因机制研究,认为该区火山岩溶蚀孔隙发育,具杏仁状充填气孔中溶孔、基质中溶孔、斑晶及角砾中溶孔、充填状裂缝中溶孔以及粒间溶孔等5种类型。熔岩中的长石斑晶、火山碎屑岩中的斜长石岩屑和由基质、火山灰水化形成的沸石类矿物在酸性介质条件下发生部分或全部溶蚀是溶蚀孔隙形成的内因,而酸性溶解液和流体介质通道的存在是溶蚀孔隙形成的外因。内因和外因共同作用导致溢流相溶解作用弱,形成的溶蚀孔隙数量少;爆发相溶解作用强,形成的溶蚀孔隙数量多。
Through a large number of core observation, combined with the identification of thin slices, scanning electron microscopy and other data, the study on the characteristics and genetic mechanism of volcanic dissolution pores in the northwestern margin of Junggar Basin shows that the dissolution pores of volcanic rocks are developed, with almond filling pores dissolved in matrix, Holes, phenocrysts and breccia dissolved pores, filled cracks in the pores and intergranular dissolved pores and other five types. The feldspar phenocrysts in lava, plagioclase cuttings in volcaniclastic rocks and zeolite minerals formed by the hydration of matrix and volcanic ash partially or completely dissolve in the acidic medium are the internal causes for the formation of dissolved pores while the acidity The existence of the solution and the fluid medium channels is the external cause of the dissolution pore formation. Due to the interaction between internal and external causes, the dissolution effect of the overflow phase is weak, and the number of dissolved pores formed is small; the dissolution phase of the explosive phase is strong, and the number of dissolved pores is large.