粤东白云嶂火山喷发盆地碱性火山岩的发现及划分

DISCOVERY AND STRATIGRAPHIC DIVISION OF ALKALIC ROCK IN BAIYUNZHANG VOLCANIC ERUPTIVE BASIN OF EASTERN GUANGDONG

东莞—惠东地区白云嶂火山盆地中侏罗—早白垩世火山岩广泛发育 ,在其上部新发现一套碱性火山岩 ,岩性主要为碱长流纹质 粗面质火山碎屑岩 ,根据其岩石学、矿物学、岩石化学、岩石地球化学、同位素年龄及与上下层位的接触关系 ,将其命名为白云嶂组。其层位位于晚侏罗—早白垩世南山村组之上、早白垩世官草湖组之下 ,其时代为晚侏罗—早白垩世。

Middle Jurassic-Early Cretaceous volcanic rock are widely distributed in Baiyunzhang volcanic eruptive basin of Dongguan-Huidong region of eastern Guangdong,where a suite of alkalic volcanic rock in upper part,mainly composed of alkali-feld-spar rhyolitic-trachytic pyroclastic rocks was discovered.In light of petrology,mineralogy,petrochemistry,petrogeochemistry,isotopic age and contact nature,the suite is named Baiyunzhan Formation.It lies between the Late Jurassic-Early Cretaceous Nanshancun Formation and lower part of the Early Cretaceous Guancaohu Formation,belonging to Late Jurassic-Early Cretaceous in age.