新生代构造抬升对地表化学风化和全球气候变化的影响

THE EFFECTS OF CENOZOIC TECTONIC UPLIFT ON EARTH SURFACE CHEMICAL WEATHERING AND GLOBAL CLIMATE CHANGE

全球新生代构造抬升 ,特别是南亚喜马拉雅青藏高原和南美安底斯山脉和Altiplano高原在新生代的抬升对地表化学风化和全球气候变化产生了重要影响。它对地表化学风化的影响主要表现为引起造山带地区化学风化能力的提高 ;而它对全球气候变化的影响则主要表现在两个方面 ,一是直接的物理影响 ,即通过对大气和海洋循环的影响来对大气变化产生作用 ;一是通过对地表硅酸盐岩石的化学风化造成大气CO2 变化和全球温度的改变 ,从而对气候变化产生间接的生物化学效应。目前看来 ,新生代构造抬升造成的大气CO2 浓度减少是造成全球新生代气候变冷的重要原因。这已得到了近 10年来计算机大气环流模型 (GCMs)数值模拟和野外实验研究的支持 ,但在关于地表化学风化的主要控制因素 ,以及海洋Sr同位素是否可作为反映地表化学风化速率变化的替代性标志和气候变化反馈机制等方面 ,还需要作进一步研究。

The global Cenozoic tectonic uplift, especially the uplift of Himalayan mountain beltTibet plateau in southern Asia,Andean mountain and Altiplano plateau in southern America, have the strong effects on the Earth surface chemical weathering and global climate change. The Cenozoic uplift might cause to increase the chemical weathering ability in orogenic belts. And the two basic categories of uplift effects on global climate change have been already recognized: (1) direct physical impacts on climate by means of changes in the circulation of the atmosphere and ocean; and (2) indirect biochemical effects on climate via changes in atmospheric CO\-2 and global temperature caused by chemical weathering of silicate rocks. The decreasing of atmospheric CO\-2 level caused by Cenozoic uplift was the main reason for the global Cenozoic cooling. Although it has already got supports from the computer GCMs simulation and the field research,the ongoing issues include, what the major controlling variation on the chemical weathering is, and that development (or validation) of the marine Sr isotope as the proxies of the average continental chemical weathering is another obvious first order need, and what the climatic feedback mechanism is,and so on.