内蒙古东乌珠穆沁旗辉音敖包一带晚侏罗世火山岩特征及时代

Zircon SHRIMP geochronology and geochemistry of Late Jurassic volcanic rocks in Huiyin Obo area of Dong Ujimqin Banner, Inner Mongolia

摘要: 提要：本文通过对工作区(内蒙古东乌珠穆沁旗辉音敖包一带)的实地勘测，将工作区内前人所取得的工作成果进行重新认识：以地层学和年代学为依据，将火山岩地层及岩石组合特征与火山活动规律相结合，将工作区内的晚侏罗世查干诺尔组及布拉格哈达组重新厘定为晚侏罗世满克头鄂博组（对比于查干诺尔组下部，SHRIMP年龄为161～153 Ma）、早白垩世玛尼吐组（对比于查干诺尔组上部，SHRIMP年龄为133 Ma）及白音高老组（对比于布拉格哈达组，SHRIMP年龄为133～129 Ma），这有利于建立地层统一的区域对比标志。

Abstract: Abstract：The main purpose of this fundamental research is to reunderstand Late Jurassic Manketou Obo Formation and Early Cretaceous Manitu Formation as well as Baiyingaolao Formation in Huiyin Obo area of Dong Ujimqin Banner, Inner Mongolia. Several sets of experiments were carried out to test the validity of the ages of three formations; these formations are comparable with Chagannuoer Formation and Bulagehada Formation from “1∶250000 Regional Geology Survey in Hesigewula Farm”. On such a basis, the authors have reached the conclusion that further research into the Mesozoic volcanic rocks in Huiyin Obo is necessary.