标志沉积层磁组构特征及其古环境意义研究

PRECINCTS OF SEDIMENTS WITH DIFFERENT ELEMENT ASSOCIATIONS AND THE SOURCES INDICATIONS IN THE CENTRAL OKINAWA TROUGH

通过对长江三角洲及其邻近区域埋藏古土壤、潮坪、长江下游河道漫滩、舟山滨岸风成沙丘、南京黄土古土壤序列沉积体的磁组构测量统计分析，取得了各自的标志特征。该标志特征揭示出，舟山滨岸风成沙丘与南京黄土古土壤序列沉积的搬运介质能量位相基本一致，其物源来向却显示出巨大差异；上述两类沉积体与上述现今潮坪、河道漫滩沉积体的搬运介质能量位相及物源来向均显示出绝然不同的标志特征。然而漫滩物源来向与南京黄土的物源来向却有众多相似之处；上述区域埋藏古土壤搬运介质的能量位相及物源来向与滨岸潮坪的相似，与舟山及南京的风成沉积相差甚远。上述标志特征揭示表明，其埋藏古土壤母质沉积与该区域风介质搬运及物源来向之间存在明显不同，却与水介质搬运及物源来向存在着亲缘关系。

Dividing sediment region using element associations is a key content of geochemical division.In our paper,51×30 geochemical data of elements from the central Okinawa Trough were treated with factor analysis.Eight factors were determined,which represented different element associations.On the basis of factor scores,the study area was divided into ten sub regions with different element associations.According to genetic attribute of element associations,the ten sub regions were given the following meanings of sources:hydrothermal volcanic mixture,volcanic hydrothermal mixture,continental volcanic mixture,biological continental mixture,volcanic material,continental material,biological material,continental volcanic biological mixture and continental volcanic biological authigenic mixture.