| Drastic environmental changes are expected in the next 10s to 100s of years when atmospheric CO2 will attain levels that were last reached during the warm Paleogene period (65.5 to 23 million years (Myrs) ago). To understand ongoing global warming and predict future environmental conditions, it is crucial to know how and when our world changed from the Greenhouse state of the Paleogene into the Icehouse state of today. The prevailing hypothesis states that global cooling was caused by uplift of the Tibetan Plateau, following the onset of the Indo-Asia continental collision. However, proving this far-sighted theory is upsetting the geosciences community because of the inability to establish unequivocal relationships between tectonism, global climate and major environmental changes in Asia. Based on expertise successfully acquired during my Veni (2005-2008), I propose a multidisciplinary study over the entire Indo-Asia collision zone to solve the problem. Three key objectives have been carefully chosen: (1) quantify and date environmental changes in exceptional sedimentary records of Northeastern Tibet; (2) date the disappearance of the large epicontinental sea formerly extending over Eurasia northwest of the Tibetan Plateau; and (3) date the Indo-Asia collision more precisely and quantify associated continental deformation. Our results will allow reconstructing the environmental response (sea retreat, aridification, cooling, monsoon intensification, biotic events) to tectonism (collision, exhumation, crustal deformation, basin formation) and to global climatic trends (Eocene-Oligocene climate transition, astronomical parameters) in unprecedented detail through time. We will provide essential boundary conditions for tectonic modelling of continental collision as well as global circulation modelling of Paleogene climate variations. |
