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海洋温度和冰量在普莱斯托时代中期的气候过渡时期的演变
H Elderfield1, P Ferretti, M Greaves
1Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK. he101@cam.ac.uk
概括
普莱斯托纪中期的过渡 (MPT) 将地球的气候周期转移到更长的10万年周期. 这种变化是由90万年前南极冰块数量突然增加引发的.
科学领域:
- 古气候学 古气候学
- 四年纪地质学四年纪地质学
- 气候动力学 气候动力学
背景情况:
- 地球的气候在普莱斯托时代中期的过渡期 (MPT) 经历了显著的变化,大约在125万到70万年前.
- 在MPT期间,主导的气候周期周期从41000年变为10万年,没有任何主要的轨道强迫变化.
- 深海基氧同位素比率,表明冰河时代和深海温度,显示了增加的变化.
研究的目的:
- 为了研究中期普莱斯托时代过渡 (MPT) 的驱动因素.
- 为了区分深海温度和全球冰体积对氧同位素比率的影响.
- 确定MPT的启动事件和时间表.
主要方法:
- 分离氧同位素比率效应归因于温度与冰体积变化.
- 分析深海的基氧同位素数据.
- 重建过去的气候动态和冰盖行为.
主要成果:
- MPT不是由逐渐冷却驱动的,而是大约在90万年前南极冰块体积急剧增加的.
- 氧同位素数据显示,在每一个冰川最大时段,气温接近零度.
- 该研究成功地解开了温度和冰体积对同位素变化的贡献.
结论:
- 南极冰层突然增加,引发了普莱斯托时代中期过渡期 (MPT).
- MPT代表了地球冰川动态的根本性转变,而不是缓慢的冷却趋势.
- 了解MPT对于理解长期的冰川-冰川间周期至关重要.
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