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標題: | "由太魯閣蓮花池孢粉分析重建臺灣東部自16,000年前以來氣候與環境變遷暨新仙女木期之探討" Reconstruction of climatic and environmental changes in eastern Taiwan since 16,000 years ago and discussion of the Younger Dryas period based on pollen analysis of Lotus Pond in Taroko National Park |
作者: | Yu-Ting Tsai 蔡育廷 |
指導教授: | 胡植慶(Jyr-Ching Hu) |
共同指導教授: | 林淑芬(Shu-fen Lin) |
關鍵字: | 孢粉,古氣候,太魯閣蓮花池,晚冰期,新仙女木事件, pollen,paleoclimate,Taroko Lotus pond,Late glacial period,Younger Dryas, |
出版年 : | 2022 |
學位: | 碩士 |
摘要: | 在臺灣古氣候研究當中,晚冰期或是老於晚冰期年代的研究相對稀少,且研究地點分散在島內各區形成各異的地方性氣候特徵。這樣的前提下,不同研究地點在同一時期/事件影響下可能會反映出不同的氣候訊息,藉由這些訊息間的相互比較可以幫助我們了解地形與季風等因子在這些氣候事件下所扮演的角色。為此,本研究選用了花蓮太魯閣蓮花池的湖泊岩芯進行孢粉分析,並輔以粒徑分析與總有機碳量分析等資料,試圖重建臺灣東部16000餘年以來的氣候與環境變化過程。 分析結果將蓮花池岩芯紀錄分為4個時期。在16100~14300 年前間,森林植被以常綠―落葉闊葉混合林為主,木本花粉佔比高反映此時期氣候條件相對適宜。在14300~12100 年前間,針葉樹種的佔比顯著上升與總有機碳含量降低表示了此時期為一個相對寒冷的時期。較粗的粒徑分布對應總有機碳含量降低,反映環境較為乾旱。本時期可再細分為前後兩個短暫的冷階段。第一個冷階段在14300~13500年前,年代上可對應到老仙女木事件。第二冷階段發生在12900~12100 年前,年代上可對應到新仙女木事件。在12100~1600 年前間,針葉樹種佔比顯著降低、常綠闊葉樹種佔比增加與較高的總有機碳含量,顯示進入此時期後氣候明顯轉暖。次生林重要樹種如九芎屬與赤楊屬佔比增加、蕨類孢子佔比漸增到後期達岩芯紀錄中最高佔比與粒度分布較前一時期來得細,顯示此時期有較高的降雨量。在1600 年前至今,艾屬、莎草科、禾本科與蓼屬等草本植物比例大增指示這時期湖盆面積可能縮減,並且由孢子佔比的下降,相較於前一時期氣候不若之前潮濕。 整體而言本研究中所記錄到晚冰期以來的氣候訊號,可與全球的晚冰期氣候波動架構相呼應。並且藉由與臺灣及東亞現有晚冰期以來古氣候紀錄比較,推論在新仙女木期間,各地降水的差異可能受控於各地受東亞冬季季風增強與夏季季風減弱的綜合影響。 Among the paleoclimate resarches in Taiwan, studies on the late glacial period or those older than the late glacial period are relatively rare and the localities are limited to only reflect the local paleoclimate conditions. Different research areas may reflect different paleoclimate information under the influence of the same period/event, and the mutual comparison of these information can help us to well understand the mechanism in these climate events.Therefore, this study selected the lake cores from the Taroko Lotus Pond in Hualien for pollen analysis, supplemented by grain size analysis and total organic carbon analysis, in an attempt to reconstruct the paleoclimatic and paleoenvironmental changes in eastern Taiwan over the past 16,000 years. . The analysis results mainly divided into four periods. Between 16,100 and 14,300 years ago, the vegetation was dominated by evergreen-deciduous broad-leaved mixed forests, and the high percentage of woody pollen indicated that the climatic were relatively warm and humid during this period. Between 14,300 and 12,100 years ago, the percentage of conifer species increased significantly and the total organic carbon content decreased, indicating that this period was a relatively cold period. A coarser grain size distribution corresponds to a decrease in the total organic carbon content, reflecting a drier environment. This period can be subdivided into two short cold periods. The first cold stage was 14,300-13,500 years ago, which could be corresponding to the Older Dryas period. The second cold stage occurred between 12900 and 12100 years ago, which could be associated with the Younger Dryas period. Between 12100 and 1600 years ago, the percentage of coniferous tree species decreased significantly, evergreen broad-leaved tree species increased, and the total organic carbon content was higher, indicating that the climate became warmer significantly. The percentage of secondary forests, such as Alnus and Lagerstroemia, increased gradually, and fern spores gradually increased to the highest percentage in the core record, and the grain size distribution was finer than the previous period, indicating that this period had higher precipitation . From 1600 years ago to the present, the percentage of herbs such as Artemisia, Cyperaceae, Gramineae, and Polygonum increased significantly, indicating that the lake basin area may have decreased during this period. Overall, the climate signals recorded in this study since the late glacial period can be corresponding to the global late glacial climate records. And by comparing with the existing palaeoclimate records since the late glacial period in Taiwan and East Asia, it infers that the difference in precipitation in different regions may be controlled by the combined effect of the East Asian winter monsoon intensification and the East Asian summer monsoon weakening during the Younger Dryad period. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/86396 |
DOI: | 10.6342/NTU202203977 |
全文授權: | 同意授權(全球公開) |
電子全文公開日期: | 2022-09-30 |
顯示於系所單位: | 地質科學系 |
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U0001-2409202218010700.pdf | 6.63 MB | Adobe PDF | 檢視/開啟 |
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