马小林^1,,
田军²,
刘丰豪²
1. 中国科学院地球环境研究所, 黄土与第四纪国家重点实验室, 陕西 西安 710061
2. 同济大学海洋地质国家重点实验室, 上海 200092

基金项目: 国家自然科学基金项目(批准号：41706071)和中国科学院地球环境研究所黄土与第四纪地质国家重点实验室培育基金项目(批准号：SKLLQGPY2002)共同资助


详细信息

作者简介: 马小林, 男, 34岁, 助理研究员, 海洋地质学专业, E-mail:maxl@ieecas.cn

中图分类号: P532;P534.61⁺2;P597⁺.2

收稿日期:2020-07-06
修回日期:2020-09-15
刊出日期:2020-11-30

The phase relationship between the benthic carbon and oxygen isotope variations on the long eccentricity band during the Cenozoic and its implication

Ma Xiaolin^1,,
Tian Jun²,
Liu Fenghao²
1. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, Shaanxi
2. State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092


MSC: P532;P534.61⁺2;P597⁺.2

--> Received Date: 06 July 2020
Revised Date: 15 September 2020
Publish Date: 30 November 2020


摘要
摘要:新生代以来地球气候依次经历了两极无冰、单极有冰和两极有冰的气候状态，对比研究这些不同气候背景下地球气候的演化历史可以为我们全面理解新生代气候演化的驱动机制提供新思路。为了探索偏心率长周期上(400 ka)气候变化与冰盖演化和碳循环之间的关系，汇总了新生代以来全球大洋10个站位底栖有孔虫成对的δ¹⁸O和δ¹³C记录，采用交叉小波、瞬时相位和滤波方法，分析了它们在偏心率长周期上的相位关系。分析结果表明，新生代大部分时段底栖有孔虫δ¹⁸O和δ¹³C在偏心率长周期上都具有较高的相关性，但是晚中新世到早上新世相对较弱。新生代底栖有孔虫δ¹⁸O在偏心率长周期上略领先δ¹³C的变化。古新世-始新世无冰期，偏心率长周期上底栖有孔虫δ¹⁸O和δ¹³C接近同相位，主要由轨道驱动的降水变化引起的营养盐-生物泵和陆源碳输入控制，该过程强调碳循环的低纬驱动。渐新世-中新世南极有冰的气候状态下；δ¹⁸O和δ¹³C的相位关系及其驱动机制与古新世-始新世类似，这表明南极冰盖对碳循环和气候变化的影响有限。此外，中新世冰盖变化引起的海平面升降导致陆架碳酸钙在冰期-间冰期旋回上的变化是促使中新世底栖有孔虫δ¹⁸O和δ¹³C在偏心率长周期上趋于同相位的一个重要原因。在中中新世气候适宜期，偏心率长周期上δ¹³C短暂领先δ¹⁸O的变化可能是由于火山除气作用导致CO₂大量入侵海-气系统所致；约13.8 Ma东南极冰盖扩张之后，偏心率长周期上δ¹⁸O开始领先δ¹³C的变化，并且相位差逐渐增大；表明东南极冰盖扩张足以通过调节大洋环流、海平面、生产力、陆源碳输入和陆地植被进一步影响大洋碳循环和气候变化。上新世以来偏心率长周期上δ¹⁸O领先δ¹³C变化，并且相位差达到了新生代的最大值(约100 ka)，表明两极冰盖的大幅度生长，已经深刻影响了碳循环和气候变化。
关键词: 新生代/
碳氧同位素/
偏心率/
相位/
冰盖/
碳循环

Abstract:The Earth's climate has experienced an ice-free world, ice-sheet at the Antarctic, and the bipolar glaciation world in sequence. This provides a unique opportunity for us to explore the mechanism of the Earth's climate evolution under different backgrounds during the Cenozoic. To explore the relationship between climate, ice-sheets, and the carbon cycle on the long eccentricity band(400 ka), we compiled coupled benthic δ¹⁸O and δ¹³C records across the Cenozoic from ten sites in the global ocean and analyzed the phase relationships between them on the long eccentricity band using the cross wavelet, instantaneous phase, and filters methods. The results show that benthic δ¹⁸O and δ¹³C records have a high correlation for the Cenozoic except for the time interval between Late Miocene and Early Pliocene. The benthic δ¹⁸O records lead slightly δ¹³C variation on the 400 ka band during the Cenozoic. During the Paleocene-Eocene ice-free world, the carbon cycles on the long eccentricity band were dominated by the nutrient-biological pump and terrestrial carbon input to the ocean caused by the precipitation variation regulated by the orbital parameters. This process emphasizes the effect of the low-latitude on the carbon cycle. Under the Oligocene-Miocene with Antarctic ice-sheet world, the phase relationship between the benthic δ¹⁸O and δ¹³C records is similar to that of Paleocene-Eocene. This suggests that the Antarctic ice-sheet has a limited impact on the carbon cycle and climate change. In addition, the glacial-interglacial variation of carbonate on the shelf resulted from the sea level changes linked with the ice-sheet is a vital factor, which leads to the in-phase relationship between the benthic δ¹⁸O and δ¹³C records on the long eccentricity band during the Middle Miocene. During the Middle Miocene Climatic Optimum, the benthic δ¹³C records lead the δ¹⁸O during a brief interval, which is mainly resulted from the massive CO₂ invasion into the sea-air system associated with volcanic degassing. Following the East Antarctic ice sheet expansion at about 13.8 Ma, the δ¹⁸O leads the δ¹³C variations again and the phase difference is gradually increasing. This indicates that the expansion of the Antarctic ice sheet is enough to affect the carbon cycle through regulating the ocean circulation, sea level, productivity, terrestrial carbon input, and land vegetation variations. The phase difference has researched the maximum(100 ka) during the whole Cenozoic, indicating the growth of the bipolar ice sheets have profoundly affected the changes in land vegetation, ocean productivity, and deep ocean water mass, hence the carbon cycle and climate change.
Key words:Cenozoic/
carbon and oxygen isotopes/
eccentricity/
phase relationships/
ice sheet/
carbon cycle



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