Sudbury Geological Discussion Group Workshop
Date: June 17, 2019
About the Workshop:
Cooling and warming has occurred many times during the Earth’s history. At times, the Earth has entirely frozen to form a ‘snowball’, while at others, it has become extremely hot, resulting in the mass extinction of species. However, despite 50 years of established plate tectonic theory, the reasons that these patterns and extremes of cooling and warming have occurred remain elusive. The speaker proposed a new model of the evolution of the Earth’s temperature that explains the planet’s thermal cycles in terms of changes in the heat balance of the system. The expansion of the lithosphere and its associated uplift lead to the collapse of Earth’s crust, and volcanism and magmatism are the global-scale response. These shallow lithospheric processes can reach a critical state with a positive feedback loop, resulting in the formation of large igneous provinces, which remove huge heat from lavas by radiating into the outer space. Endothermic phase changes during the de-compressive melting also absorb large quantities of heat from the inner Earth and cool their surroundings. This process may terminate the warming cycle and initiate a new cooling cycle, possibly an ice age.
Dr. C.A. Tang, as a chair Professor (funded by Cheung Kong Scholar Programme from State Education Ministry), is the Director of the Center for Rock Instability and Seismisity Research (CRISR) of Dalian University of Technology. He is also the Vice President of the Chinese Society of Rock Mechanics CSRM, and the China National Group Chairman of International Society of Rock Mechanics.
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