关键词: 湖泊沉积岩芯, 元素地球化学特征, 环境变化记录, 桂林岩溶湿地

Abstract:

         Sedimentation rates and element concentrations  of core sediments from Sihu Lake are investigated and characteristics
of element geochemistry and environmental change around  this  lake are discussed. By using principal component analysis,  the
geochemical composition factors affecting the sediments of the cores are mainly four: the erosion factor, the watershed runoff and
diagenesis factor, the regional background effect factor and the human activity effect factor. The latter two factors usually account
for smaller proportions. However,  in recent years  the human  factor has rapidly numerical  increase because of quick  increase of
phosphorus contents  in  lake sediments. On  the other hand, variations  in chemical elements obviously have periodic  feature:  the fourth period (0-4 cm, corresponding to 1987-2007), is mainly affected by human activities closely related with regional economic
development. The other earlier  three periods  (4-20 cm, corresponding  to 1894-1987; 20-53 cm, corresponding  to 1703-1894;
53-77 cm, corresponding to 1562-1703) were mainly controlled by climate change.

Key words: lake sedimentary core, element geochemistry, environmental change records, Guilin wetlands