南秦岭北大巴山造山带火山碎屑流堆积特征

北大巴山造山带南华系龙潭河组火山碎屑岩分布于城口至高观一带。它与一般正常火山碎屑岩如空降火山碎屑岩、沉凝灰岩等有很大区别,通过野外观察及系统薄片鉴定,认为它具有典型的普里尼式三相火山碎屑流堆积模式特征,这对于进一步合理划分地层具有重要意义及分析古火山口构造环境具有重要意义。

Pyroclastic rocks of Nanhua series Longtanhe formation in Northern Daba Mountains orogenic belt are mainly distributed in the area of Chengkou and Gaoguan. It is a big difference from ordinary pyroclastic rock, such as the airborne pyroclastic rock and sedimentary tuff. By field observation and system chip identification, the authors think that Longtanhe formation has the accumulation mode of typical Plinian type eruption three-phase pyroclastic flow. This has a great significance for appropriately dividing strata and analyzing tectonic environment of the ancient crater.