������ظ���¡���°���ͳ������㰵ɫ���ң�Ϊ�˻ָ����װ�ɫ���ҵĹŻ�����������ϵͳ��Ұ����ʵ����ȡ������������ѧ������ʾ: Sr/Ba ��ֵΪ 0. 08 ��0. 20��̼��ͬλ��ϵ�� Z ֵΪ 106. 62 ��116. 03�������°���ͳΪ��ˮ�����������ζȱ仯����ȶ�; Ti ����Ϊ 3 183 × 10 ^��6 �� 5 239 ×10 ^��6 ��Sr/Cu ��ֵΪ 2. 53 ��35. 84��Fe/Mn ��ֵΪ 21. 15 �� 96. 95�������°���ͳ������ůʪ�������������; Cu/Zn ��ֵΪ 0. 09 ��0. 21��V/V + Ni ��ֵΪ 0. 77 ��0. 81��Ce ���쳣ָ��Ϊ ��0. 06 ��0. 01�������°���ͳ���ڻ�ԭ�����С��߷ۻ�ʯ������ʾ: Protopodocarpus sp�� (ԭʼ�޺��ɷ� δ����)�� Aratrisporites fischeri (Klaus) Playford et Dettmann (��Ъ����㵥����) ����ָʾ��ֲ����������Ϊ��ůʪ������򻷾�����Դ��Ԫ�ص���ѧ����ָʾ���׵ز���нϺõ�����ǰ������ůʪ��Ļ�ԭ����Ϊ�л��������ṩ�����õ�������

Based on systematic geological survey and sampling analysis��this paper restores the palaeoenviron- ment of dark mudstone of Lower Cretaceous largely developed in Fujin uplift of Sanjiang Basin�� The geochemical characteristics show that ratio of Sr/Ba varies from 0. 08 to 0. 20 and coefficient of carbon and oxygen isotopes va- ries from 106. 62 to 116. 03��which indicates the Lower Cretaceous developed in a freshwater sedimentary environ- ment with stable salinity�� Content of Ti varies from 3 183 ×10 ^��6 to 5 239 ×10 ^��6 ��ratio of Sr/Cu varies from 2. 53 to 35. 84 and ratio of Fe/Mn varies from 21. 15 to 96. 95��which indicates the Lower Cretaceous developed under warm humid climate conditions�� And��ratio of Cu/Zn varies from 0. 09 to 0. 21��ratio of V/ (V + Ni) varies from 0. 77 to 0. 81 and abnormal index of Ce varies from ��0. 06 to 0. 01��which indicates the Lower Cretaceous devel- oped in a reducing environment�� The palynological fossils��Protopodocarpus sp�� and Aratrisporites fischeri (Klaus) Playford et Dettmann indicate warm and humid environment for the plants growing�� Geochemical characteristics of source rocks indicate a prospect for gas generation��and the warm and humid reductive environment provided fa- vourable condition for organic matter��