IGA NEW YEAR LECTURE Wednesday, 9th February, 2011
Speaker: Prof. John Gamble (University College Cork)
VENUE: J.M. Synge Theatre, Arts Block, Trinity College, Dublin
(Pedestrian entrance opposite the bottom of Dawson Street.)
Volcanism is the spectacular end-product of magmatic processes that are testimony to the high temperatures and dynamic processes in the deep interior of our planet. The magma generation process is one of partial melting, whereby a source rock partially melts, the melt segregates and then leaves behind a refractory residue.Ê Partial melting can take place in the upper mantle, producing basalt from peridotite, or the crust, to produce a wide range of magmas extending from andesite to dacite and rhyolite. Moreover, magmas are intrinsically less dense, and can experience secondary modification through crystal fractionation, assimilation, mixing, mingling and degassing as they ascend to the surface. These complex and intertwined mixing processes are fundamental to the generation of continental crust that has a bulk composition of andesite. Using andesites as an example, the talk will examine the deep interior of the planet and the processes generating continental crust.