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Evolution of the late Mesozoic magmatic systems in Hong Kong: New perspectives from zircon geochronology and trace element analyses, by Denise Tang
April 22, 2017 @ 10:30 AM - 11:00 PM UTC+0
(GEO/CEDD, Hong Kong)
Denise graduated from the Department of Earth Sciences, HKU and joined the Geotechnical Engineering Office (GEO) as a graduate trainee in 1999. Since then, she has dedicated herself to the geology profession, and been working at the GEO for over 15 years. Denise co-authored the popular geology book “Hong Kong Geology – A 400-million year journey”, which has been one of the GEO’s best seller publications since its publication in 2009. Denise obtained her MPhil degree from the Department of Earth Sciences HKU in 2007, and has recently completed her PhD study at the Victoria University of Wellington, New Zealand.
About the talk
Spatial and temporal correlation of four late Mesozoic volcanic centres and their sub-volcanic plutons are well-constrained in Hong Kong. Of the four volcanic episodes, the youngest caldera-forming eruptions (of c. 140 million years ago) from the High Island Caldera have been interpreted to be of super-eruption scale. Multiple techniques including field studies, zircon SIMS geochronology and trace element analyses have been employed to gain new insights into the evolution of these ancient volcanic systems. The results show that in individual large volcanic systems, source composition and temperature may change over millions of years, and thereby generate two distinctly different groups of volcanic and granitic products. In this talk, some latest findings of Hong Kong’s magmatic history and their implications to our understanding of Yanshanian orogeny will be presented.