�ȷ汱ɽ���������������Ϊ�����������Һ�ʯӢ�������ҡ������������Ҿ��и߹衢������ƺ�ƶþ������; ��ϡ��Ԫ�� (L��EE) ��Ը�������ϡ��Ԫ�� (H��EE) ��Կ������������쳣; ������������ʯԪ�� (LILE) ��b��Th��K������߳�ǿԪ�� (HFSE) Nb��Ta��P��Ti �ȣ�����ѧ������ʾ�����ڹ����ʸƼ��� I �ͻ����ҡ�����ʯӢ�������Ҿ��и����þ��ƶ�׵���������ϡ��Ԫ�� (L��EE) ��Ը�������ϡ��Ԫ�� (H��EE) ��Կ��������쳣; ������������ʯԪ�� (LILE) ��b��Th��K �ȣ�����߳�ǿԪ�� (HFSE) Nb��Ta��P��Ti �ȡ�����ѧ������ʾ������׼���ʸ߼ظƼ�����ʯ�������������Ҽ�ʯӢ�������ҵ� La- -ICP- -MS U- -Pb ͬλ�ز������ֱ�Ϊ 128. 3 ±2. 6 Ma �� 113. 2 ±1. 7 Ma��Ϊ���������������ɽ�����������ϣ���Ϊ�ȷ汱ɽ�����������Һ�ʯӢ���������ǹ�̫ƽ���鹹�������ɼ�ѹ��Ϊ��չ�����µIJ��

Granodiorite porphyry and diorite porphyry exposed in the Xianfengbeishan gold deposit�� The authors studied the chronology of the dikes and the tectonic setting�� The results indicate that the granodiorite por- phyry was emplaced in the Early Cretaceous with age of 128. 3 ± 2. 6 Ma��belonging to peraluminous medium- K calc- alkaline I- type granites��and display characteristics of high silicon��alkali and calcium and low magnesium�� They are enriched in light rare earth elements (L��EEs) and large ion lithophile elements (LILEs; e. g�� ��b��Th�� K)��and depleted in heavy rare earth elements (H��EEs) high field strength elements (HFSEs; e. g�� Nb��Ta��P and Ti) with on obvious Eu anomalies�� Meanwhile��the diorite porphyry was emplaced in the Early Cretaceous with age of 113. 2 ±1. 7 Ma��belonging to metaluminous high-K calc- alkaline rocks��and featured by high alkali and magnesium and low phosphorus�� They are characterized by enrichment in light rare earth elements (L��EEs) and large ion lithophile elements (LILEs; e. g�� ��b��Th��K)��depletion in heavy rare earth elements (H��EEs) high field strength elements (HFSEs; e. g�� Nb��Ta��P and Ti) with on Eu anomalies�� Based on the geological data in the Wandashan region��it is proposed that the granodiorite porphyry and diorite porphyry from the Xianfengbeishan were emplaced in a transformation setting from convergence to extension��which was closely related to the subduc- tion of the Paleo- Pacific Oceanic plate and the amalgamation of the Jiamusi and Wandashan blocks��