辽南早元古代花岗岩的变形温度及其构造意义

DEFORMATION TEMPERATURE OF EARLY PROTEROZOIC GNEISSIC GRANITE FROM SOUNTHERN LIAONING PROVINCE AND ITS TECTONIC SIGNIFICANCE

辽南早元古代辽河群中片麻状花岗岩的变形温度显示出645—690℃,550—610℃和485℃±三组温度值,表明花岗岩遭受了三幕构造变形。而区域构造解析亦表明辽河群在早元古时期经历了三幕构造变动。花岗岩的温度系列与区域变形序列具有一致性,排除了花岗岩晚期构造侵位的可能性。变形温度以550—610℃居多,意味着该幕构造形迹保存最好。第三幕变形变质作用相对较弱,仅局部出现485℃的温度值。

Twenty-eight deformation temperature were obtained from gneissic granite in Early Proterozoic Liaohe Group, which can be derided into three series, 645—690℃, 550—610℃ and 485℃±. They record three episodes of deformation. The regional structural analysis shows that Liaohe Group underwent three episodes of deformation. The three deformation temperature series of granite is consistent with the three regional deformation series. Deformation temperature of the first episode indicats the emplacement of granite is earlier than the second episode deformation. The deformation temperature of second episode is most widespread, which is in agreement with the view that the tectonic framework of Liaohe Group was formed during that deformation episode. The third deformation episode is local, represented by few deformation temperature arbund 485℃.