MIO-PLIOCENE GROWTH OF THE TIBETAN PLATEAU AND EVOLUTION OF EAST ASIAN CLIMATE
MIO-PLIOCENE GROWTH OF THE TIBETAN PLATEAU AND EVOLUTION OF EAST ASIAN CLIMATE
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发表时间：
2005
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通讯作者：
P. Molnar
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作者：
P. Molnar
在过去的15年里，许多研究不仅报道了6-8 Ma的生态和气候变化，而且还报道了青藏高原周围地区大致同时发生的构造过程。这些生态变化证实了印度次大陆北缘转向更干旱气候的说法，这首先是由在巴基斯坦工作的脊椎动物古生物学家提出的。最近的一些观测扩大了西藏北部和东北部干旱加剧的地区。此外，有证据表明，在8 Ma附近，阿拉伯海和南中国海的风场同时变得更像今天的风场，分别以印度季风和东亚季风为主。构造过程的开始可能是对青藏高原平均海拔上升约1000-2000米的响应，几乎在所有情况下都不像生态和气候变化那么精确；更大的平均海拔应该会增加高原边缘的偏向压应力，足以启动这些地区的变形。深层构造过程与地区性(如果不是全球)环境变化之间的联系太诱人，不容忽视，但各种观测结果在时间和相互影响上的不一致绝不需要这样的联系，或者西藏平均海拔发生这样的变化。我客观地回顾了各种观察结果，既是为了显示潜在的相关性，也是为了揭露这些不一致之处。
During the past 15 years, numerous studies have reported not only ecological and climatic changes at 6-8 Ma, but also the roughly concurrent onsets of tectonic processes in regions surrounding the Tibetan Plateau. The ecological changes corroborate suggestions of a switch to a more arid climate on the northern margin of the Indian subcontinent, which were first made by vertebrate paleontologists working in Pakistan. Some of the more recent observations extend the region of increased aridity north and northeast of Tibet. Moreover, some evidence suggests that near 8 Ma, the wind fields over the Arabian and South China Seas simultaneously became more like those of the present day, which are dominated by the Indian and East Asian monsoons, respectively. The onsets of tectonic processes, which in nearly all cases are less precisely dated than the ecological and climatic changes, could have occurred as responses to a ~1000-2000-m increase in the mean elevation of the Tibetan plateau; a greater mean elevation of this amount should raise deviatoric compressive stresses on the margins of the plateau sufficiently to initiate deformation of these regions. The link between deep-seated tectonic processes and regional, if not global, environmental change is too tantalizing to ignore, but inconsistencies in timing and in mutual implications of the various observations by no means require such a link, or that such a change in Tibet’s mean elevation occurred. I review the various observations objectively both to show the potential correlations and to expose these various inconsistencies.