Invited by Prof. Hongrui Fan in the Key Laboratory of Mineral Resources, Chinese Academy of Sciences, Dr. Andrew Tomkins from Monash University, Australia, visited Institute of Geology and Geophysics from June 1 to 10, 2010. During his visit, Dr. Tomkins investigatedXincheng, Jiaojia and Linglong gold deposits in the Jiaodong peninsular accompanying by Prof. Fan. On June 10, Dr. Tomkins presented a lecture titled by “The Source of Gold in Granite-Bearing Metamorphic Belts”.

Andrew Tomkins received his PhD from the Australian National University in 2002. He undertook post-doctoral research at the University of Calgary in Canada, and then took up a 5-year research fellowship at Monash University in Melbourne, Australia. He is now a lecturer in economic geology and metamorphic petrology at Monash University. Dr Tomkins received the Lindgren Award from the Society of Economic Geologists in 2008, for excellence in early career research. He is an Associate Editor for the journal Economic Geology. He is conducting research that combines economic geology, metamorphic and igneous petrology, and structural geology to study metallogenic processes. He is also investigating a range of mid-to deep-crustal processes that influence metal distribution and mobility including: sulfide melt immiscibility in magmatic mixing zones at the base of arcs (MASH zones) and its role in ore genesis; the P-T-t-D window (s) for metamorphic generation of sulfur-rich hydrothermal fluids; the behaviour of metals during silicate anatexis; and sulfide partial melting during metamorphism.

In his talk, Dr. Tomkins firstly introduced gold sources in the orogenic gold deposits. He thought that large volumes of rocks in the middle to deep crust underwent metamorphic dehydration. The escaping fluids scavenge trace quantities of gold from these same rocks. Metamorphic fluid generation probably promotes deformation, which in turn drives fluid migration. Tectonic processes that subject large volumes of crust to a progression of high T, low P metamorphism create the most favorable gold source conditions. Then, he introduced gold sources in the granite-related gold deposits based on analysis of Challenger and Griffin’s Find, South Australia. He considered that gold can be physically extracted from granitic melts.