【摘要】：不同尺度的氣候研究日益成為古氣候、古環(huán)境恢復(fù)的熱點(diǎn),地處中高緯、靠近格陵蘭冰蓋的北大西洋海域一直是近幾年來(lái)研究的重點(diǎn)。本文根據(jù)西格陵蘭海域連續(xù)沉積鉆孔GA306-GC3(后面簡(jiǎn)稱為GC3孔),發(fā)現(xiàn)該孔中的硅藻能直觀反映中晚全新世以來(lái)西格陵蘭海域古海洋環(huán)境變化及其主要影響因子。 對(duì)GC3孔中的硅藻進(jìn)行前期處理、制片和鑒定,通過(guò)對(duì)89個(gè)玻片鑒定發(fā)現(xiàn)沉積物中硅藻含量十分豐富,總計(jì)鑒定出107種硅藻,其中常見(jiàn)硅藻主要包括：Bacterosira bathyomphala、Fragilariopsis cylindrus、Fragilariopsis oceanica、 Thalassionema nitzschioides、Thalassiosira antarctica var. boreal休眠孢子、 Thalassiosira nordenskioeldii、Thalassiosira oestrupii、Rhizosolenia hebetata f. semispina、Rhizosolenia borealis和Thalassiosira hyalina等。 運(yùn)用古環(huán)境分析專業(yè)軟件Tilia和C2對(duì)硅藻數(shù)據(jù)進(jìn)行聚類分析和主成分分析,發(fā)現(xiàn)兩者結(jié)果間存在很好的一致性,自上而下還將硅藻劃分出相同的組合帶,共同反映了該地區(qū)6700年以來(lái)氣候逐漸變冷的過(guò)程,具體變化過(guò)程主要包含以下3個(gè)階段： 6650—3950cal. a BP期間暖水硅藻含量豐富且活躍,表層海水溫度較高,為全新世大暖期,后期大西洋暖水對(duì)該區(qū)域的影響有所減弱,氣候逐漸轉(zhuǎn)冷,暖水種含量呈小幅減小,冷水種含量隨之波動(dòng)上升,標(biāo)志著暖期結(jié)束。 3950—1650cal.a BP期間硅藻含量變化強(qiáng)度明顯高于上一階段,尤其以3000a.BP為界,前期由于印明格暖流影響增加,暖水種硅藻含量波動(dòng)增加。3000—1650a.BP期間因受寒流影響,而極地、海冰種含量大幅增加。 1650—130cal. a BP期間因寒流影響繼續(xù)加強(qiáng),暖水硅藻含量降至極小值,海冰和極地硅藻始終高值震蕩,但在1000cal. a BP前后極地種和海冰種含量突然降至低值,可能與中世紀(jì)暖期有關(guān)。 GC3孔化石硅藻記錄不僅與鄰近格陵蘭島上的冰芯記錄(GSIP2)溫度曲線間存在良好的對(duì)應(yīng)關(guān)系,同時(shí)還與相鄰區(qū)域其他資料對(duì)比也有很好的一致性,這些資料共同記錄了該北半球中高緯地區(qū)中晚全新世以來(lái)的降溫趨勢(shì),同時(shí)還反映出幾次典型氣候變化事件(如全新世大暖期、黑暗時(shí)代冷期、中世紀(jì)暖期、小冰期等)。
[Abstract]:The climate research of different scales has become the hot spot of the ancient climate and the restoration of the ancient environment, and the North Atlantic sea area close to the Greenland ice cover has been the focus of the research in recent years. According to the continuous deposition of G306-GC3 (hereinafter referred to as the GC3 hole) in the West Greenland sea area, it is found that the diatoms in this hole can directly reflect the changes of the ancient marine environment and its main influencing factors in the West Greenland sea area since the Holocene. The diatoms in the GC3 wells were pre-treated, tabletted and identified, and a total of 107 diatoms were identified by the identification of 89 slides, including: Bacterosira baathyomphala, Fragilariopsis cylindus, Fragilariopsis ocellica, Thalassiona nitzschioides, Thalassirosira antarctica va. r. Boreal dormant spores, Thalassiosira nodenskoeldii, Thalassiosira oesupii, Rizzosolenia heteata f. semispinina, Rizzosolenia borneis and Thalassiosira hyalina Based on the analysis of the cluster analysis and the principal component of the diatom data by the ancient environment analysis professional software, Tilia and C2, it is found that there is a good agreement between the two results, and the diatom is divided into the same combination zone from top to bottom, which reflects the gradual cooling of the climate since 6700 years in the region. the process of the specific change mainly comprises the following three steps: Stage:6650-39 During the period of 50 cal. a BP, the content of the warm water is rich and active, the temperature of the surface sea water is high, the influence of the warm water in the late Atlantic on the region is weakened, the climate is gradually cooled, the content of the warm water is small, and the content of the cold water is increased and the mark At the end of the warm-up period, the change of diatom content during the period of 3950 to 1650 cal. a BP is obviously higher than that of the previous stage, especially at the boundary of 3000a. BP, and the fluctuation of the content of the diatom in the warm water is increased due to the influence of the warm-flow of the Inmin.3000-1650a. BP, which is affected by the cold flow during the BP, and the polar and sea-ice. A significant increase in the content of species. During the period of 50 to 130 cal. a BP, due to the influence of the cold flow, the content of the warm water diatom is reduced to the minimum value, and the sea ice and the polar diatoms always oscillate at high value. however, that content of the polar species and the sea ice before and after 1000 cal. a BP is suddenly reduced to a low value, The GC3-hole fossil diatom record not only has a good correspondence with the ice core record (GSIP2) temperature curve on the adjacent Greenland island, but also the other resources of the adjacent area The comparison of materials also has good consistency, which together record the cooling trend of the middle and high-latitude regions in the Northern Hemisphere since the Holocene, and also reflects several typical climate change events, such as the new world of the world and the cold period of the dark times.
【學(xué)位授予單位】：華東師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：P532;P736.22

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