Hong Kong – Under the guidance of a top tier professor in earth science, Hong Kong University (HKU) final year student, Jessie Kwan Longching’s year-long research on the formation of ~2.5 billion year-old high-temperature metamorphic rocks (granulites) in Eastern Hebei, was published in the leading international peer-reviewed journal Gondwana Research, demonstrating international recognition of the outstanding ability of HKU undergraduate students in conducting scientific research.
Jessie’s paper was actually produced from the result of her final year project. In this project, Jessie carried out a detailed study on ~2.5 billion year-old granulites exposed in Eastern Hebei (North China) using a modern thermodynamic modeling technique THERMOCALC, different from former studies.
Although Chinese geologists have been carrying out research on metamorphic rocks in Eastern Hebei as well as other metamorphic terrains in North China over the past 20 years, former studies were mainly based on inconsistent and conventional methods (geothermobarometric calculations) in determining the pressure-temperature conditions of metamorphic outcrops, which may result in large errors. It therefore remains highly controversial whether or not these findings reflect the true metamorphic history of the area instead of being artifacts of the traditional calculations.
The result of Jessie’s research demonstrates that the metamorphic process of the Eastern Hebei granulites is characterised by an anticlockwise pressure-temperature evolution with time (P-T-t path) involving cooling at constant pressure, which is generally considered to reflect an origin related to the intrusion and underplating of large amounts of mantle-derived magmas, not in accordance with modern plate tectonics like what happened in Himalaya Mountains.
As Jessie’s supervisor, Prof Zhao Guochun of Department of Earth Sciences (HKU) thinks that Jessie’s result is very important because it provides insights into understanding the controversial issue of whether or not plate tectonics was operative during Archean (>2.5 billion years) time.
Prof Zhao Guochun, ranked 9th in the top 1% geoscientists (comprising 3,277 members) worldwide, is a distinguished researcher at HKU Department of Earth Sciences. His lectures on metamorphic geology captured Jessie’s interest during her undergraduate study and further led to her decision in conducting relevant research supervised by Prof Zhao.
“The department has fully supported my research through providing research equipment such as petrological microscopes and Electron Probe Micro-Analyzer (EPMA), which is the only one of its kind in Hong Kong, as well as research funds,” Jessie said. “As a beginner to the world of academic research, I am grateful to the support staff, lab technicians and postgraduate students in the department for their generous help and support.”