辽西四合屯地区义县期火山作用对沉积环境的影响

辽西四合屯地区中生代火山活动发育,广泛分布着火山作用形成的爆发相、溢流相火山岩.在显生宙地球历史中,如此巨大且迅速的火山作用普遍被认为是巨大种群灭绝的原因.与火山作用相联系的沉积相是火山作用间歇期形成的冲积扇-河流相、滨湖相、半深湖-深湖相,这些沉积相提供了研究火山作用对沉积环境影响的依据.义县期火山作用对沉积环境影响包括:义县期各沉积环境火山作用产物及火山岩风化产物的充填;各沉积相被当地多期(次)火山岩控制并埋藏于其下的火山-沉积相组合由下至上“螺旋式“规律性变化;义县期火山作用引起地表抬升与构造地形的变化,从而影响排流模式的变化;经历火山作用影响的生物群提供了义县期气候变化证据.

Influences of Yixianian Volcanism on Sedimentary Environment in Sihetun Area, West Liaoning

Volcanic eruption facies and flooding facies are extensively developed in the Sihetun area, west Liaoning. Such voluminous and rapid volcanic activities in Phanerozoic have commonly been thought to be a cause for zoobiocenose extinction. The alluvial-fluvial, shore-shallow lacustrine, semi-deep and deep lacustrine facies were developed during volcanic dormancies, which provide evidence to study the influences of volcanism on sedimentary environment. The influences include: infilling of both volcanic and weathering materials; burial and control by multiphased volcanic activities and upward changes of volcanic-sedimentary facies associations; the Yixianian volcanic activities initiated crustal uplift and tectono-topographic changes, which in turn affect draining modes; the biota experiencing volcanism influences can be evident for climate change.