High-resolution decording of terrestrial paleo-climate recorder in laminated tufas

层状凝灰岩陆地古气候记录仪的高分辨率解码

• 批准号: 12640443
• 负责人: KANO Akihiro
• 金额: $ 2.05万
• 依托单位: Hiroshima University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640443/
• 关键词: tufas; carbonate; paleo-climate; stable isotopes; minor elements; シアノバクテリア; 炭酸塩堆積物

A tufa, a freshwater carbonate deposited in a limestone area, is an excellent tool for quantitative and highresolution analysis of terrestrial paleo-climate. Results of our investigation reveal that 1) laminated texture of tufas can be treated as annual layering developed due to seasonal change in precipitation rate of calcite. Estimation of microbial biomass shows that 2) the precipitation is not induced by photosynthesis of cyanobacteria living on the tufa surface. This and results of chemical analyses conduct to the conclusion that 3) equilibrium in terms of oxygen stable isotope and minor metal elements is confirmed in the calcite precipitation.These contexts make paleo-climatic analyses using a laminated tufa possible, and the analyses were performed for the specimens collected from Shirokawa (Ehime Prefecture) and Niimi (Okayama Prefecture). We found that 4) oxygen isotopic composition changes very regularly together with annual layering. The change is reflected from regular seasonal change in water temperature. Furthermore, we realized that 5) rainfall events are recorded as brown-colored bands, which are rich in Si, and Al. Excellent correlation between positions of the bands and periods of the rainfall events was recognized.This study provided new aspects of depositional processes and conditions of laminated tufas, and confirmed importance of the tufas in terms of paleo-climatological analytical tools

石灰华是沉积在石灰岩地区的淡水碳酸盐岩，是定量和高分辨率分析陆地古气候的极好工具。研究结果表明：（1）石灰华的层状结构可以看作是方解石沉淀率随季节变化而形成的年成层结构;微生物生物量的估算表明：2）降水不是由石灰华表面蓝藻的光合作用引起的。这一点和化学分析的结果得出的结论是，3）氧稳定同位素和微量金属元素在方解石沉淀方面的平衡得到证实。这些情况使使用层压石灰华进行古气候分析成为可能，并对从白川（爱媛县）和新见（冈山县）采集的样品进行了分析。我们发现，4）氧同位素组成的变化非常有规律的年度分层。这种变化反映在水温的季节性变化上。此外，我们还认识到，5）降雨事件记录为富含Si和Al的棕色条带，这些条带的位置与降雨事件的时间具有很好的相关性，这一研究为层状凝灰岩的沉积过程和条件提供了新的方面，并证实了凝灰岩在古气候分析工具方面的重要性

项目成果

Tomoko, Kojo: "Examination of photosynthetically-induced hypothesis for tufa deposition by evaluation of organic/inorganic carbon production ratio"Journal of Sedimentological Society of Japan. Vol. 53. 71-73 (2001)

Tomoko, Kojo：“通过评估有机/无机碳生产比率来检验光合作用诱导的钙华沉积假说”日本沉积学会杂志。

古城智子: "有機/無機炭素生産量比からのトゥファ堆積における光合成誘導仮説の検証"堆積学研究. 53. 71-73 (2001)

Tomoko Kojo：“从有机/无机碳生产比率验证凝灰岩沉积物中的光合作用诱导假说”沉积学研究 53. 71-73 (2001)。

狩野彰宏: "淡水成炭酸塩堆積物の同位体に記録される陸上気候"名古屋大学大気水圏科学研究所共同利用報告書. 88-91 (2001)

Akihiro Kano：“淡水碳酸盐沉积物同位素记录的陆地气候”名古屋大学大气和水圈科学研究所联合使用报告88-91（2001）。

Ahiro Kano: "Origin of the gross morphology and internal texture of tufas of Shirokawa Town, Ehime Prefecture, southwest Japan"Journal of Geological Society of Japan. Vol. 106, no. 6. 397-412 (2000)

鹿野博宏：“日本西南部爱媛县白川镇凝灰岩的总体形态和内部结构的起源”，日本地质学会杂志。

Akihiro Kano: "Terrestrial climates recorded in isotopic compositions of freshwater carbonate deposits"Annual Reports of Cooperative Res. IHAS, Nagoya Univ.. 88-91 (2001)

嘉纳昭宏：“淡水碳酸盐沉积物同位素组成中记录的陆地气候”合作研究年度报告。