4:00 PM -4:30PM
Mr. DING Anyang Department of Earth Sciences, HKU
The Archean rock record shows little sign of modern plate tectonics, but the very tectonic mode governing the Archean Earth is still under debate. It has been proposed that the Neoarchean may have witnessed the transition to plate tectonics of our planet Earth. Therefore, understanding the Neoarchean geological activities should be one of the primary issues to address. Most Archean outcrops in the North China Craton are ca. 2.6-2.5 Ga in age, and a 2.48 Ga granulite-facies metamorphic event was also recorded within the craton. Such rock record makes the North China Craton one of the best areas in the world to study the Neoarchean crustal growth and the nature of the Archean-Proterozoic transition. The northern Liaoning terrane locates at the northeastern corner of the North China Craton, composed mainly of TTG gneiss with belts of supracrustal rocks. The supracrustal rock sequence, the Qingyuan Group, is not well studied yet, and the structure of the terrane remains controversial as well. TTG domes were mapped out by Sun et al. (1993), and a plume model with crustal diapirism was proposed by Wu et al. (2013). Top-to-the-northwest thrusting structure with cyclic crustal formation was recognized by Wang et al. (2017), and they regard the northern Liaoning terrane as a Neoarchean accretionary orogen. More work needs to be carried out to understand the Neoarchean crustal growth and deformation in this area and the tectonic mode those activities lie in.
Additional information: Mr. Ding Anyang, email@example.com