THE MIDDLE MIOCENE CLIMATIC TRANSITION - EAST ANTARCTIC ICE-SHEET DEVELOPMENT, DEEP-OCEAN CIRCULATION AND GLOBAL CARBON CYCLING
THE MIDDLE MIOCENE CLIMATIC TRANSITION - EAST ANTARCTIC ICE-SHEET DEVELOPMENT, DEEP-OCEAN CIRCULATION AND GLOBAL CARBON CYCLING
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DOI：
10.1016/0031-0182(94)90251-8
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发表时间：
1994-04-01
影响因子：
3
通讯作者：
KENNETT, JP
中科院分区：
文献类型：
--
作者：
FLOWER, BP;KENNETT, JP
中中新世代表了新生代气候演化的一个重大状态变化，它紧随早中新世晚期约1600万年前新近纪温暖期的高峰之后。这次气候转变的早期阶段（约1600万到1480万年前）以全球气候、东南极冰盖（EAIS）体积、海平面和深海环流的重大短期变化为特征。在后期阶段（约1480万到1290万年前），气候发展包括东南极冰盖的大幅增长以及相关的南极变冷，经向温度梯度明显增加，海平面大幅波动随后全球海平面下降，以及深海环流的重要变化，包括南大洋水（Southern Component Water）产量增加。东南极冰盖的增长和极地变冷也对全球碳循环和陆地生物圈产生了重大影响，包括中纬度大陆地区的干旱化。1480万年后东南极冰盖稳定性的增加是新近纪晚期全球气候系统建立的关键一步。是什么控制了极地气候和东南极冰盖的这些变化呢？深海环流变化可能在极地气候的演化和变化中起到了重要作用，就像它们在整个新生代所起的作用一样。来自特提斯东部/北印度洋温暖、咸的深水形成的氧和碳同位素证据表明，向南极的经向热量输送在中中新世早期（约1600万到约1480万年前）抑制了新生代极地变冷和东南极冰盖的增长。据推测，在约1600万到1480万年前，温暖的低纬度源（来自特提斯东部 - 北印度洋）和寒冷的高纬度源（南大洋水）之间的竞争可能与南极气候和冰冻圈的不稳定有关。约1480万年前流向南大洋的温暖、咸的深水流量减少可能降低了向南极的经向热量输送，使该地区变冷并导致南大洋水产量增加。南极的这些中中新世气候和冰冻圈变化对海洋和陆地气候产生了深远影响。随着经向地表温度梯度增加，气候带之间的边界加强，导致澳大利亚、非洲以及北美洲和南美洲的中纬度大陆地区干旱化加剧，促进了草原的发展并刺激了食草哺乳动物的进化。
The middle Miocene represents a major change in state in Cenozoic climatic evolution, following the climax of Neogene warmth in the late early Miocene at approximately 16 Ma. The early stage of this climatic transition from approximately 16 to 14.8 Ma was marked by major short term variations in global climates, East Antarctic Ice Sheet (EAIS) volume, sea level, and deep ocean circulation. In the later stage from approximately 14.8 to 12.9 Ma, climatic developments included major growth of the EAIS and associated Antarctic cooling, a distinct increase in the meridional temperature gradient, large fluctuations in sea level followed by a global sea level fall, and important changes in deep water circulation, including increased production of Southem Component Water. East Antarctic ice sheet growth and polar cooling also had large effects on global carbon cycling and on the terrestrial biosphere, including aridification of mid-latitude continental regions. Increased stability of the EAIS after 14.8 Ma represents a crucial step in the establishment of late Neogene global climate systems.What controlled these changes in polar climates and the East Antarctic ice sheet? Deep ocean circulation changes probably played a major role in the evolution and variation in polar climates, as they have throughout the Cenozoic. Oxygen and carbon isotopic evidence for warm, saline deep water production in the eastern Tethyan/northern Indian Ocean indicates that meridional heat transport to the Antarctic inhibited Cenozoic polar cooling and EAIS growth during the early middle Miocene from approximately 16 to approximately 14.8 Ma. Inferred competition between warm low-latitude sources (derived from the eastern Tethyan-northern Indian Ocean) and a cold high-latitude source (Southem Component Water) from approximately 16 to 14.8 Ma may have been associated with instability in the Antarctic climate and cryosphere. Reduction of warm, saline deep water flow to the Southern Ocean at approximately 14.8 Ma may have decreased meridional heat transport to the Antarctic, cooling the region and leading to increased production of Southern Component Water.These middle Miocene climatic and cryospheric changes in the Antarctic had profound effects on marine and terrestrial climates. As the meridional surface temperature gradient increased, boundaries between climatic zones strengthened, leading to increased aridification of mid-latitude continental regions in Australia, Africa and North and South America, enhancing the development of grasslands and stimulating the evolution of grazing mammals.