高精度鍶同位素測量在全球環境變遷研究上的潛力應用(I)

• Main Author: 游鎮烽
• Other Authors: 地球科學系
• Format: Report
• Language: Chinese; English
• Published: 2003
• Subjects: 鍶同位素; 水團示蹤劑; 古氣候變遷; Strontium isotope; water mass tracer; paleo- climatic variations; Planktonic foraminifera
• Online Access: http://ir.lib.ncku.edu.tw/handle/987654321/55200; http://ir.lib.ncku.edu.tw/bitstream/987654321/55200/1/2010400503002.pdf

計畫編號:NSC92-2119-M006-005 執行機構:成功大學地球科學系（所） 研究期間:2003-08~2004-07 鍶同位素已廣泛被應用於地球科學領域各學門研究；包括古海洋、同位素地層學、大陸化學風化作用、河海交界處水體與沈積物之動力學作用等。本計畫利用甫於成大地科系研發成功的高精度鍶同位素質譜分析術（<5 ppm, 2σ），首次系統性探討海水中87Sr/86Sr 的垂直分布情形及海洋水團示蹤劑之潛力應用，同時並評估浮游有孔蟲殼體鍶同位素比作為古海洋環境代用指標的可能性及所蘊含之古氣候意義。藉由結合南海地區其他環境代用指標（如：Mg/Ca, Sr/Ca, Ba/Ca）將可更精確重建南海古海洋環境的變遷。此計畫的初步成果有：1.建立台灣附近東北海域及南海地區海水鍶同位素剖面，同時評估海水87Sr/86Sr 作為水團示蹤劑之可能性；2.系統性評估浮游性有孔虫殼體鍶同位素與海水之平衡關係; 3.初步探討南海中長期海洋87Sr/86Sr 與冰期-間冰期古氣候變遷之可能關聯性。 The stable isotopes of strontium have been applied extensively for researches in Earth Sciences, including paleoceanography, isotope stratigraphy, chemical weathering rate, dynamic interaction between water and sediment at the estuarine environment. Under this proposal, we have developed successfully of high precision（<5 ppm, 2σ） Sr TIMS technique at NCKU for a systematical investigation of vertical distribution of 87Sr/86Sr in seawater profiles, as well as to explore potential application of 87Sr as sensitive water mass tracer. Furthermore, we have evaluated the Sr isotopic compositions in planktonic foraminifera as paleoceanographic proxy and its potential plaeo-climatic significance. The results were combined with Mg/Ca, Sr/Ca and Ba/Ca data in South China Sea for re-constructing possible environmental changes in the past, including temperature, rainfall or monsoon. Under this proposal, we have finished the following works: (1) establish the vertical profiles of seawater 87Sr/86Sr around the northern part of South China Sea and offshore northeastern Taiwan, and investigate seawater Sr IC as potential tracers in marine geochemistry; (2) systematic investigation of Sr isotope equilibrium between foraminiferal shells and seawater 87Sr/86Sr; (3) To evaluate the possible correlation of long-term seawater 87Sr/86Sr and glacial-interglacial climate changes in the South China Sea.