本文選題：快速氣候變化 + 南海西南海區(qū)　； 參考：《中國(guó)科學(xué)院研究生院（海洋研究所）》2014年碩士論文

【摘要】：詳細(xì)研究低緯海區(qū)古水文環(huán)境的演化模式及其與高緯地區(qū)的聯(lián)系，對(duì)于千百年尺度快速氣候變化機(jī)制的認(rèn)識(shí)具有重要意義。以南海西南巽他陸坡CG2巖芯為材料，通過(guò)浮游有孔蟲Globigerinoides ruber殼體的δ18O和Mg/Ca重建了近24ka以來(lái)的表層海水溫度（SST）和鹽度（SSS），結(jié)合沉積物粒度和浮游有孔蟲定量統(tǒng)計(jì)數(shù)據(jù)重建了末次盛冰期（LGM）以來(lái)南海西南海區(qū)上部水體環(huán)境的演化歷史。 結(jié)果顯示，在YD、H1、8.2ka冷事件期間，巽他陸坡區(qū)鹽度變高，浮游有孔蟲暖水種豐度減少，溫躍層變淺，沉積物砂和粉砂含量增加，粘土含量減少，平均粒徑增大，而B/A暖期以及YD事件后期的響應(yīng)特征正好相反。相比開放大洋末次冰消期的緩慢變暖，南海西南海區(qū)B lling早期以及YD事件后期升溫迅速，且H1期間具有明顯的降溫，幅度達(dá)1.5℃，是典型的“格陵蘭式”升溫。快速氣候變化期間，ITCZ南北的緯向移動(dòng)，造成東亞冬季風(fēng)和夏季風(fēng)的反向突變，使得東亞季風(fēng)影響下的南海南部海區(qū)在冷事件的變冷以及末次冰消期的快速轉(zhuǎn)暖在時(shí)間相位上幾乎與格陵蘭冰芯的記錄一致。LGM期間海平面降低，水系發(fā)育，表層海水鹽度比現(xiàn)今低1.15‰。冰消期，海平面變化和東亞夏季風(fēng)的強(qiáng)弱變化造成了海水鹽度頻繁的波動(dòng)，通過(guò)對(duì)鹽度變化做頻譜分析，發(fā)現(xiàn)了全新世以來(lái)南海南部海區(qū)660年的夏季風(fēng)演變周期。在H1、YD期間，東亞夏季風(fēng)突然減弱，，鹽度變高，B/A暖期夏季風(fēng)增強(qiáng)，鹽度變低，比較發(fā)現(xiàn)在這些氣候事件期間東、西太平洋站位的鹽度變化特征幾乎是一致的。LGM以來(lái)熱帶西太平洋海區(qū)的上層海水環(huán)境變化與熱帶輻合帶（ITCZ）的緯向移動(dòng)及其相關(guān)的東亞季風(fēng)異常有密切聯(lián)系。
[Abstract]:A detailed study of the evolution model of paleohydrological environment in low-latitude sea area and its relationship with high-latitude area is of great significance to the understanding of the mechanism of rapid climate change in thousands of years. Taking the CG2 core on the Sunda continental slope in the southwest of the South China Sea as the material, By means of 未 18O and Mg/Ca of planktonic foraminifera Globigerinoides ruber shell, the surface water temperature and salinity since 24ka have been reconstructed. Combined with sediment granularity and quantitative statistical data of planktonic foraminifera, we have reconstructed the southwestern South China Sea area since the last sub-glacial age. The evolution history of the upper water environment. The results show that the salinity of Sunda continental slope becomes higher, the warm water abundance of planktonic foraminifera decreases, the thermocline becomes shallower, the sediment sand and silt content increase, the clay content decreases and the average particle size increases during the YDU H1 + 8.2ka cold event. The response characteristics of B / A warm period and late YD event are opposite. Compared with the slow warming of the last stage of the open ocean ice, the early stage of B lling and the late stage of the YD event in the south-west South China Sea are rising rapidly, and the temperature of the H1 period is obviously decreased by 1.5 鈩

本文編號(hào)：1836101