吉林槽区的早古生代地层

THE PALEOzOIC STRATA OF THE JILIN GEOSYNCLINAL AREA

吉林槽区的早古生代地层可分为寒武系呼兰群及奥陶系辽源群。呼兰群以含双峰式火山岩建造及硅铁建造为特征，反映拉张型被动大陆边缘构造环境；辽源群以含钙碱性火山岩建造及块状硫化物为特征，反映挤压型活动大陆边缘岛弧构造环境。辽源群弯月组上部为区域金、银、铜、铅、锌重要含矿层位。

The early Paleozoic strata can be divided into the Cambrian Hulan Group and the Or-dovician Liaoyuan Group.The Hulan Group is Characterized by double peak─type volcanicrock formation and silicated iron formation,showing structural setting of the extensional pas-sive continental margin. The Liaoyuan Group is characterized by the calc─alkaline volcani-crock formation and massive sulphides,showing island arc structural setting of the compres-sional mobile continental margin. The upper part of the Wanyue Formation of the LiaoyuanGroup is major regional ore bearing bed with gold,silver,copper,lead and zinc.