�������Ͽ���λ�ڽ���������������������ܿ����鱱�������̵Ĵμ����ѡ���������������������Ϊ�����ʯ LA--ICP--MS U--Pb ���ѧ�о����������������γ���94. 2 ±2. 0 Ma���������������ϵ�����������������������������������һ�ں�����Һ��ʹ1#���������ڳɿ���ӵ����������������������ɿ��ں�������������--�������ڡ��������е��о��ɹ�����Ϊ��Զ������������Ⱥ����Ϊͬһʱ�ڹ��챳���µIJ��������������������--�����ɿ����þ������й�ϵ���������ҳɿ����ô���̫ƽ������Ի�����鸩�嵼�µĻ������Ż�����

Bunan gold mine of Jinling gold deposit was located in the northwest of Jiaodong gold province�� controlled by the secondary faults of Ling--Bei fault�� LA--ICP--MS zircon U--Pb dating showed that the orthoclase porphyry formed in Late Cretaceous (the weighted average age 94. 2 ±2. 0 Ma)�� ��esearches showed that another stage of hydrothermal solution rose with the invision of orthoclase porphyry��and led to the superimposition of the major mineralization period of gold in Early Cretaceous and polymetallic-gold-silver mineralization in Late Creta- ceous�� Based on the existing research results��acidic dyke swarms of Zhaoyuan area were formd in the same tecton- ic setting and had a close connection with polymetallic-gold-silver mineralization in Late Cretaceous�� It is suggested that the petrologenesis and mineralization were under the geodynamic setting of back-arc extension due to the sub- duction of Pacific Plate��