Ϊ̽��ȫ���������Ϻ������������ij��������仯���Ա����庣��� SO- - 31 ��������״��������Ԫ�ص���ѧ����������Ԫ�ص���ѧ�Ĵ���ֲ��������� SO- - 31 ����������Ϊ 3 ����Ԫ����ӳ��ȫ������ͬʱ�ڵ�����ƽ�沨���Լ���������Դ�ı仯��SO - - 31 ��������ϡ��Ԫ��������ߺ� La/Co �� La/Sc ɢ��ͼ��������: ��11 400 ��12 800 a BP (ȫ����ǰ��)���о�����ƽ��ϵͣ���ӡ������ܱߺ�����������ʴ���Ϊ��������Ҫ��Դ; ��8 500 ��1 1400 a BP (ȫ��������)�����ź�ƽ������������ӿںͰ����𽥺��ˣ�����Դ�������Ա���������Ĺ�����Ҳ��������Ӧ�仯����Զ��Ժ�ӹ����������½�; ��0 ��8 500 a BP (��ȫ��������)������ƽ������������������ݺ�Ͽ�򿪣�������ˮ������������Դ���������˾�䣬��ӶԱ�������Դ�����𽥱�С�������Ա����嶫�������ʳ�Ϊ�������������Ҫ��Դ��

In order to understand the changes of depositional environment during the Holocene��the authors carried out geochemical investigations of the core sediments SO- - 31 from the Beibu Gulf��South China Sea�� The SO - - 31 core sediments were divided into 3 sedimentary units according to vertical geochemical distribution�� which indi- cated the changes of sea level and the variation of sediments provenance in the studying regions�� Distribution pat- terns of rare earth elements (��EEs) and the scatter diagram of La/Covs La/Scof core SO- - 31 sediments suggest: �� 11 400 ��12 800 a BP: Beibu Gulf had relatively low sea level��the ��ed ��iver and the western Hainan Island pro- vided most materials to the studying area; �� 8 500 ��11 400 a BP: The recession of the estuary and the coastline was due to sea level rising��and the contribution of provenance supply areas changed and that of the ��ed ��iver de- creased; �� 0 ��8 500 a BP: With the opening of the Qiongzhou Strait��the provenance and hydrodynamic condi- tions of the Beibu Gulf had undergone a significant change��and the materials from western Hainan Island and east- ern Qiongzhou Strait became the main sources for the core sediments��while ��ed ��iver��however��contributed only little to the core sediments��