Journal of Metamorphic Geology

Cover image for Vol. 35 Issue 4

Edited By: Michael Brown, Katy Evans, Doug Robinson, Richard White and Donna Whitney

Impact Factor: 3.673

ISI Journal Citation Reports © Ranking: 2015: 3/47 (Geology)

Online ISSN: 1525-1314

Geochronology in partially melted rocks

An important goal in studies of crustal melting is to link P–T determinations with time, particularly to understand rates of heating, lengths of melting episodes and rates of cooling and exhumation. Although accessory minerals with a high closure temperature for diffusion of Pb, for example monazite and zircon, are most suitable for dating close to peak P–T conditions for partially melted rocks, linking to a P–T point or range along the P–T path presents challenges since these minerals may survive from the precursors, recrystallize around peak conditions or exhibit new growth as melt crystallizes along the retrograde path. Nowadays these alternatives potentially may be discriminated using microstructural characterization, micro-beam chemical analysis, accessory phase thermometry and trace element distributions between accessory minerals and associated rock-forming minerals to provide constraints on whether grains are relict from the precursor or record the timing of recrystallization and/or new growth in relation to the P–T evolution.

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