基浪堆积物(岩)地质特征及其地质意义

Geological features and significance of base-surge deposits

刘招君 苗巧银 刘祥 柳蓉

Liu Zhaojun Miao Qiaoyin Liu Xiang Liu Rong

基浪堆积物(岩)被认为是一种特殊的火山碎屑物(岩),主要是岩浆在上升的过程中与地表水或地下水相作用发生爆炸,冲破上覆岩层,并伴随出现基浪沉积而成的水成火山碎屑物,火山爆炸为基浪堆积物提供充足的物质来源.增生火山砾及发育的大型似沙丘构造是基浪堆积物(岩)的典型指相标志,可以和其他火山碎屑岩相区别;在碎屑结构上基浪堆积中多为火山豆、火山砾,多呈半圆状,少数为圆状,个别呈次棱角状.由于基浪堆积物兼具有火山碎屑及沉积岩的特征,因此可作为良好的油气储集体:而且对其成因的研究可起到防灾预警的作用.

Base-surge deposits,commonly considered as a special kind of pyroclastics,are aqueous pyroclastics that are produced by explosive magma-water interaction.Volcanic explosion provides rich material resources for base-surge.Base-surge deposits are characterized by accretionary lapilli and large-scale dunelike structures,therefore they can be easily differentiated from other volcanoclastic rocks.The clastic texture of base-surge deposits is dominated by volcanic pisolite and gravel mostly in half-round shape,followed by round shape,and some in subangular shape.Since base-surge deposits have some characters of pyroclastic debrits and sedimentary rocks,they serve as excellent oil and gas reservoirs.In addition,study on its genesis is helpful for preventing and forecasting disaster.

10.11743/ogg20080102