Benthic Foraminifera Response To Changes In Paleoenviornments Of Mud Area On The East China Sea Shelf

In this article，qualitative and quantitative research and analysis based onbenthic foraminifera group of C0803column collected from Fujian and Zhejiang mud area and CFJ103column collected from the the Jeju Island mud area,combined with210Pb dating, was used to research the changes in paleoenviornments of Mud area on the East China Sea in the past502years，and to discuss the feasibility conditions of this method.The study found that there are abundant benthic foraminifera in C0803column and CFJ103column of the mud area in the East China Sea shelf. In C0803column most are narrow temperature、normal salinity、semi-deep water species and low-salt、shallow-water species, with a small amount of warm-water species. In CFJ103column most are narrow temperature、normal salinity、semi-deep water species, low-salt、shallow-water species and cold-water species.The age of the bottom of C0803column is approximately170years ago.According to the study，C0803column can be divided into six combinations. Combined with foraminifera ecological characteristics the study found:(1) During the1840-1875year in the continental shelf of the East ChinaSea water mass forces more powerful and prosperous, affected by seawater salinity in the area tended to be normal;(2) During1876-1902, Fujian and Zhejiang coastal current impact has beenenhanced, water temperature and salinity are low;(3) During1903-1955, Fujian and Zhejiang coastal current is significantlyweakened, Taiwan Warm forces enhanced increase in sea water temperature andsalinity. (4) Flow into the strong peak of Fujian and Zhejiang coast since1956and continues to this day.At the bottom of CFJ103column age about502years ago. Through the analysis of benthic foraminifera CFJ103column combination of characteristics,502years ago Jeju mud area southwest ocean currents and water mass changes,have been divided into the following three phases:(1) During the1507-1553year, the Yellow Sea cold water mass forces aremore powerful and prosperous, low sea water temperature;(2) During the1554-1694year, the strong, the salinity in shelf water massforces become normal;(3) Strong peak flow and flow into the Yellow Sea coast of the Yellow Sea coast since1695, the low temperature and salinity.C0803column the benthic foraminifera deposition record Fujian and Zhejiang coastal current changes in the170years since the East Asian winter monsoon intensity has a good agreement, but CFJ103column can not do a very good resolution. Speculated at the time of a few hundred years ago, in more stable sedimentary environment, by continuous encryption sampling and high-precision of benthic foraminifera analytical tools reflect the marine environment and climate change in the scale of decades,under conditions only in the depositionrate is larger (≥1.129cm/a) of the best results.