�����ɵؿ��ϲ��Ϲ�������˹�����м�ʯӦ��LA--ICP --MS U --Pb ���ԵĽ����ʾ��4 ����Ҫ�������: 263 �� 378 Ma ( ��ֵ����274 Ma) ; 405 �� 547 Ma ( ��ֵ515 Ma) ; 660 �� 974 Ma ( ��ֵΪ 923 Ma) ; �����Ϊ��Ԫ�Ŵ�����1 165 Ma��1 369 Ma��1 476 Ma��1 517 Ma������������һ���ʯ����263 ± 2 Ma ��������˹�������������������; �� 274 Ma �ķ��������븽�������Ĵ�ʯկ���ɽ�Һ͵����ҽ��ҵ�����һ��; �� 515 Ma �ķ��������붫�����������ڻ��ױ������ҵ�����һ��; ����Ĺ����������ӳ�����ɵؿ���׵���Ϣ��������ɵؿ�ı����Ϲ������������顢��������ͼ��Ͷ�Ե�����������м�ʯ���䣬��ʾ���ɵؿ�Ӧ����̫�Ŵ���Ԫ�Ŵ��ı��ʻ��ף�Ϊ������ز��ṩ�˷ḻ����Դ�����ɵؿ�ӦΪһ���ȶ���΢�ؿ飬�����dz��ڻ����ɽ����

The authors studied the detrital zircon aging from the Upper Paleozoic Zhesi Formation in southern Songliao block�� The U--Pb dating of detrital zircon from the Zhesi Formation by LA--ICP MS technique showed 4 major age groups: 263 �� 378 Ma ( peak age as 274 Ma) ; 405 �� 547 Ma ( peak age 515 Ma) ; 660 �� 974 Ma ( peak age 923 Ma) ; and the fourth group including 1 165 Ma��1 369 Ma��1 476 Ma and 1 517 Ma�� The youngest zircon age of 263 ± 2 Ma represents the lower limit of the deposition age of the Zhesi Formation��in which the peak age 274 Ma is consistented with the ages of the surrounding volcanic rocks and island arc magmatic rocks in Dashizhai Formation�� The peak age 515 Ma showed the age of the Pan-African metamorphic complex in NE China�� The rest old ages reflect the information of basement in Songliao block�� Considered the ages of the detrital zircon aging of the Upper Paleozoic strata such as the Tumenling Formation in northern Songliao block��Benbatu Formation in western Songliao block and Heilongong Formation in eastern Songliao block��it is suggested that the Songliao block had Archean and Proterozoic metamorphic basement��providing rich source of material for the Paleozoic sediments�� The fact indicats that the Songliao block was more likely a stable micro continental block rather than long-term activities of orogenic belt��