本文選題：重慶羊口洞 + δ~(18)O�。� 參考：《西南大學(xué)》2015年碩士論文

【摘要】：全球變暖問(wèn)題己成為全球關(guān)注的焦點(diǎn)。全球氣候變化不再僅僅是一個(gè)學(xué)科問(wèn)題,而日漸成為當(dāng)今人類(lèi)社會(huì)最為關(guān)注的重大社會(huì)問(wèn)題,與人類(lèi)的生存環(huán)境密切相關(guān)。末次冰期最典型的氣候變化特征是一系列百年-千年尺度的氣候波動(dòng),即Heinrich (H)事件和Dansgaard-Oeschger (D/O)循環(huán)。目前由于缺乏高分辨率、精確定年的地質(zhì)記錄,關(guān)于一系列H事件的起止和持續(xù)時(shí)間以及內(nèi)部結(jié)構(gòu)等特征還存在爭(zhēng)議,其氣候驅(qū)動(dòng)機(jī)制也尚未被完全認(rèn)識(shí)清楚。相對(duì)于黃土、冰芯、湖泊等記錄,洞穴石筍具有高分辨率、精確定年、記錄氣候和環(huán)境信息完整等優(yōu)勢(shì),已成為當(dāng)前相關(guān)研究領(lǐng)域的重要載體之一。本文以重慶金佛山羊口洞YK1和JFYK7石筍為研究對(duì)象,利用高精度的230Th測(cè)年技術(shù)以及氧穩(wěn)定同位素記錄,建立了該地區(qū)末次冰期高分辨率的古氣候變化時(shí)間序列,并與全球其它地質(zhì)記錄進(jìn)行對(duì)比,利用RAMPFIT擬合方法對(duì)H1-H6事件進(jìn)行了標(biāo)定,并分析了其與其它地質(zhì)記錄所記錄的H事件起止時(shí)間的相位差,以及內(nèi)部結(jié)構(gòu)的異同。進(jìn)而探討亞洲季風(fēng)環(huán)流格局,以及與格陵蘭地區(qū)和南極地區(qū)溫度變化的關(guān)系。通過(guò)分析羊口洞石筍YK1和JFYK7高分辨率的δ18O記錄,發(fā)現(xiàn)YK1和JFYK7石筍符合Hendy檢驗(yàn)標(biāo)準(zhǔn),且兩者具有很好的重現(xiàn)性,因此可以利用石筍YK1和JFYK7的氧穩(wěn)定同位素記錄進(jìn)行古氣候重建。通過(guò)對(duì)比,證明了羊口洞石筍記錄的H事件與其它地質(zhì)記錄的吻合性,說(shuō)明羊口洞石筍能反映當(dāng)時(shí)的氣候變化,共同受控于亞洲夏季風(fēng)的變化,在H事件發(fā)生期間,亞洲夏季風(fēng)減弱,石筍δ18O明顯偏重。在長(zhǎng)時(shí)間尺度上太陽(yáng)輻射曲線與石筍δ18O變化有很好的對(duì)應(yīng)關(guān)系,但在一些短時(shí)間尺度的變化上二者并沒(méi)有很好的對(duì)應(yīng)關(guān)系�？赡苁且�?yàn)槭Sδ18O的影響因素除太陽(yáng)輻射外,還有很多其它因素,主要有溫度、降水量和蒸發(fā)量、冬夏降水量比值、水汽來(lái)源和大氣環(huán)流等。利用重慶羊口洞石筍YKl和JFYK7以及其它地區(qū)地質(zhì)記錄的氧同位素?cái)?shù)據(jù),通過(guò)RAMPFIT方法進(jìn)行擬合,標(biāo)定了Heinrich事件的起止時(shí)間,并通過(guò)全球?qū)Ρ确治隽似鋬?nèi)部結(jié)構(gòu)變化特征。與同處在亞洲季風(fēng)區(qū)的新崖洞、小白龍洞、董哥洞、葫蘆洞、三寶洞記錄對(duì)比表明,亞洲季風(fēng)區(qū)千年尺度大氣降水氧同位素組成變化在大范圍上具有空間一致性。但是羊口洞石筍具有更準(zhǔn)確的年齡和更高的分辨率,使得H事件的標(biāo)定更為可靠。H1-H6事件在東亞季風(fēng)區(qū)的石筍中的記錄,反映的是夏季風(fēng)減弱,與北大西洋格陵蘭冰芯中記錄的溫度降低相對(duì)應(yīng)。此外印度季風(fēng)區(qū)的石筍中也記錄了此類(lèi)事件,同樣代表夏季風(fēng)強(qiáng)度減弱。而南半球的石筍氧同位素則與亞洲石筍相反,即在H事件期間,南半球夏季風(fēng)和西風(fēng)強(qiáng)度增強(qiáng),與南極冰芯記錄的溫度升高相吻合。這也說(shuō)明了南北半球氣候變化在千年尺度上的反相位關(guān)系。但是各地質(zhì)記錄的變化模式并不是完全一致的,反映了地域差異。亞洲季風(fēng)區(qū)石筍記錄H2、H3以及H4事件的變化模式與南極冰芯EDML溫度記錄的變化模式相似,說(shuō)明末次冰期時(shí)東亞夏季風(fēng)除了能反映北半球高緯度地區(qū)的信號(hào)外,還會(huì)受到南半球溫度變化的影響。北大西洋經(jīng)向環(huán)流(AMOC)是亞洲冬夏季風(fēng)氣候突變的主要原因,北高緯的氣候信號(hào)主要通過(guò)西風(fēng)帶來(lái)影響到亞洲夏季風(fēng)的強(qiáng)弱,進(jìn)而影響到石筍氧同位素和黃土中值粒徑的變化。北大西洋地區(qū)的氣候和亞洲季風(fēng)遙相關(guān),是因?yàn)樘?yáng)輻射減弱時(shí),格陵蘭地區(qū)的溫度降低,海陸熱力差異減小,導(dǎo)致亞洲夏季風(fēng)減弱。H事件發(fā)生期間,西伯利亞高壓增強(qiáng),北半球溫度降低,此時(shí)熱帶輻合帶(ITCZ)向南移動(dòng),導(dǎo)致亞洲冬季風(fēng)增強(qiáng)且持續(xù)時(shí)間增長(zhǎng),而夏季風(fēng)環(huán)流減弱。ITCZ的南北移動(dòng)是由南北半球的溫度梯度引起的,ITCZ趨向更暖的半球。ITCZ的南北移動(dòng)與北大西洋經(jīng)向環(huán)流(AMOC)有關(guān),AMOC減弱,由此導(dǎo)致海洋向北傳輸?shù)臒崃繙p少,海表溫度降低,北半球變冷,ITCZ向南移動(dòng)。
[Abstract]:Global warming has become the focus of global concern. Global climate change is no longer a subject matter, but is increasingly becoming the most important social problem in human society today. It is closely related to the living environment of human beings. The most typical climate change in the last glacial period is a series of century - Millennium scale climate fluctuations, that is, He The inrich (H) event and the Dansgaard-Oeschger (D/O) cycle. Currently, due to the lack of high resolution, precise annual geological records, the beginning and end time and internal structure of a series of H events are still controversial, and its climate driving mechanism has not yet been fully recognized. The bamboo shoots have the advantages of high resolution, accurate dating, record the integrity of climate and environmental information, and have become one of the important carriers in the current research field. This paper takes the YK1 and JFYK7 stalagmite of Jinfu goats in Chongqing as the research object. The high precision 230Th dating technique and the oxygen stable isotope record have been used to establish the high end glacial period in this area. The resolution of paleoclimate change time series is compared with other geological records in the world. The RAMPFIT fitting method is used to calibrate the H1-H6 event, and the difference between the phase difference and the internal structure of the H events recorded by the other geological records is analyzed, and the Asian monsoon circulation pattern is discussed, and the Geo mausoleum is also discussed. The relationship between the temperature changes in the orchid area and the Antarctic region. Through the analysis of the YK1 and JFYK7 high-resolution Delta 18O records of the goat mouth cave, it was found that the YK1 and JFYK7 stalagmite were in conformity with the Hendy test standard, and both had good reproducibility. Therefore, the oxygen stable isotopic records of the stalagmite YK1 and JFYK7 could be used to reconstruct the paleoclimate. The H events recorded in the sheep cave stalagmites coincide with the other geological records, indicating that the Asiatic stalagmite can reflect the climate change at that time, which is controlled by the changes in the Asian summer monsoon. During the H event, the Asian summer monsoon weakened and the stalagmite Delta 18O was significantly heavier. On a long time scale, the solar radiation curve and the stalagmite Delta 18O were very good. The corresponding relationship, but there is not a good correspondence between the two of the short time scales, maybe because of the influence factors of the stalagmite Delta 18O except for the solar radiation, there are many other factors, mainly temperature, precipitation and evaporation, the ratio of winter and summer precipitation, the source of water vapor and the circulation of the atmosphere, and the use of Chongqing's oromouth cave of YKl and J FYK7 and the oxygen isotope data of geological records in other regions are fitted by RAMPFIT method to calibrate the beginning and stop time of Heinrich events and to analyze the characteristics of their internal structure changes through global comparison. The records of the new cliff cave in the Asian monsoon region, the small white Dragon Cave, Dong Ge cave, the gourd cave and the three treasure cave show that the Asian monsoon The variation of the oxygen isotope composition of the atmospheric precipitation in the Millennium scale has spatial consistency in a large range. But the goat mouth cave stalagmites have more accurate age and higher resolution, making the calibration of the H event more reliable.H1-H6 events in the stalagmite of the East Asian monsoon region, reflecting the weakening of the summer monsoon and the Greenland ice core in the North Atlantic. In addition, this kind of event is also recorded in the India monsoon area, which also indicates that the intensity of the summer wind is weakened. The oxygen isotope of the southern hemisphere is contrary to the Asian stalagmite, that is, during the H event, the summer monsoon and the westerly intensity in the southern hemisphere are enhanced, which is also consistent with the increase in the temperature of the Antarctic ice core. The anti phase relation of climate change on the Millennium scale in the northern and southern hemisphere is clear, but the variation patterns of the geological records are not completely consistent, reflecting regional differences. The variation patterns of H2, H3 and H4 events in the Asian monsoon region are similar to that of the EDML temperature records in the Antarctic ice core, indicating the East Asian summer in the last glacial period. The North Atlantic meridional circulation (AMOC) is the main reason for the abrupt change in the winter and summer climate in Asia. The climate signals of the northern high latitude are mainly influenced by the westerly wind to influence the Asian summer monsoon and the oxygen isotope and yellow of the stalagmite. The climate of the North Atlantic region and the Asian monsoon teleconnection are due to the decrease in the temperature of the Greenland and the decrease of the thermodynamic differences in the Greenland region when the solar radiation is weakened, resulting in the weakening of the Asian summer monsoon during the.H event, the increase in the high pressure in Siberia, the lower temperature of the north half of the ball, and the southward movement of the tropical convergence zone (ITCZ) at this time. The Asian winter winds increased and continued to increase, while the summer monsoon circulation weakened the North-South movement of.ITCZ, which was caused by the temperature gradient in the northern and southern hemispheres. ITCZ tends to be related to the North-South movement of the warmer hemisphere and the North Atlantic meridional circulation (AMOC), and the AMOC is weakened, thus reducing the heat transfer to the north of the ocean and reducing the temperature of the sea surface, and the temperature of the sea surface is reduced. The northern hemisphere is colder, and ITCZ moves southward.
【學(xué)位授予單位】：西南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：P532

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相關(guān)期刊論文 前3條

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本文編號(hào)：1996071