北淮阳地区中生代火山活动及其构造背景

通过总结近年来北淮阳地区的１∶５万区调资料及有关专题研究，认为该区中生代火山活动可分为两个旋回，两个岩浆系列。第一旋回和信阳—商城火山喷发带的第二旋回为钙碱性系列；金寨—舒城火山喷发带中的第二旋回为碱性系列。钙碱性系列岩浆起源于３０～７０ｋｍ深的陆内聚合带；碱性系列为造山后期恢复阶段张性条件下的产物。其总体特征是由东向西酸性增强，起源深度渐浅。

THE MESOZOIC VOLCANIC ACTIVITIES AND THEIR TECTONIC SETTINGS IN THE NORTH HUAIYANG AREA

By summarizing the recent years of data of 1:50000 scale regional survey and related subject study on the North Huaiyang area, the author concludes that the Mesozoic volcanic activities in the area may be divided into two cycles and two magmatic series: The first cycle and the second cycle of the Xinyang-Shangcheng volcanic eruption belt that belong to calca-alkalic rock series are derived from the intracontinental convergence zone;the second cycle of the Jinzhai-Shucheng volcanic eruption belt that falls into alkalic is a product of late orogenic process at recovery stage under extensional circumstances.In general,they are characterized by the increasingly acidic rocks and decreasing depth of derivation westward.