辽北辽河群和下二台群

Northern Liaoning Liaohe Group and Xia’ertai Group

辽北辽河群有别于辽东辽河群。铁岭、开原地区的为震旦 早寒武世蛇绿杂岩； 在法库一带则属下二台群。下二台群是一套巨厚的火山 沉积建造， 其下部的火山岩为岛弧火山岩， 它与碳酸盐岩之间有银的富集， 其时代为奥陶纪。

The Northern Liaoning Liaohe Group is utterly different from the Liaohe Group in the Eastern Liaoning province. Recent research indicates that “N.Liaoning Liaohe Group” in Tieling and Kaiyuan consists of paleooceanic crust residue of ophiolite complex,and the formation time is Sinianearly Cam?brian,and “N.Liaoning Liaohe Group” in Faku district is Xia’ertai Group. The Xia’ertai Group is a series of enormous thick volcanovolcanogene sedimentary formation.The island arc volcanic rocks are under this Group.There is a concentration of silver between volcanic rocks and carbonate rocks.The Xia’ertai Group formation time is Ordovician.