�ۺ��о��������౦ɽ���������������ز㡢���ﻯʯ��ͨ��������������ʯ����ѧ�����ʯU--Pb ͬλ�ز������ϣ������õ������������������������Ϊ��������ز㣬������������Ϊ��½����������ز㣬��ʯ̿��Ϊ½��Ӻ������ز㡣�౦ɽ���趫�ϲ��¶һ������Ϊ( 300 ± 3 �� 357 ± 4) Ma �Ļ����ң���������������������������Ϊ����ɽ�����ң��������Ϊ��ɽ��A �ͻ����ҡ������౦ɽ����������������ʼ�պϣ�����ʯ̿��Ϊ½��Ӻ���������ʯ̿��—�������Ϊ̧����ʴ�׶Ρ�����Ϊ�౦ɽ��������ʯ̿����ʼ��ɽ����ʯ̿�����ڻ������������������ɽ����չ���á�

The Paleozoic sedimentary strata��fossils��geochemistry of intrusive rocks and the zircon U--Pb isotopic dating of Duobaoshan in Heilongjiang Province have been comprehensively studied�� They are the marine sedimentary strata from Early Ordovician to the early Late Devonian��sea-land interbeddind sediments in the late Late Devonian��and the continental fluvial and lacustrine deposits in Early Carboniferous�� It is exposed a set of granites with ( 300 ± 3 �� 357 ± 4) Ma in southeastern Duobaoshan marine basin�� Syenite fine-grained and adamellite finegrained mylonites are post-orogenic granites��and alkali granites are post-orogenic granites in A-type�� That means the Duobaoshan marine basin closed from Late Devonian��became continental sedimentary in Early Carboniferous�� and in uplift and erosion stage in Late Carboniferous-Early Permian�� The fact performed that the orogeny of Duobaoshan area began in Early Carboniferous��and post-organic extension continued from Late Carboniferous to Late or Early Permian��