Paleoenvironment Changes Of Nansha Waters Since Last Glacial

Paleoenvironment changes were discussed in Nansha Water since Last Glacialbased on systematic study of Core NS94-93 and NS94-24. During last glacial,water exchange was very poor and sediments are dominated by terrigenous matter,accompanying with higher CCD and intensive dissolution of carbonate. SundaShelf was drown by seawater at l3. 2kaBP ¹⁴C age(14. 9 kaBP Cal age) and becamestable after about 600a. Summer monsoon was weak and unstable during lastglacial. Afterward, water exchange was evidently intensified when Sunda Shelfwas completely drown out, and biogenous matters in sediments was markedlyincreased. Research also testified the existence of Heinrich 1(13. 4-13. 8kaBP ¹⁴Cage), Older Dryas Cooling Event(12. 1-12. 4kaBP ¹⁴C age), Younger Dryas CoolingEvent(10-11. 2kaBP ¹⁴C ages), but the temperature drops of these events were verysmall. In Nansha Waters, Holocene began at 10kaBP ¹⁴C age, and the temperaturedidn't evidently raised during the Preboreal period(10-8. 7kaBP ¹⁴C age). After8. 7kaBP, climate of Nansha Waters behaved unstably and cyclically, and achievedwarmest period at 4. 4kaBP. The climate of Nansha Watrs simultaneously changedwith global climate, and could trace by the changes of monsoon and hydrologyindex, supported that the global changes was mainly caused by atmospherecirculation.