The metamorphic record preserved in the Alpine Schist accretionary wedge complex offers a unique opportunity to investigate the timing of these processes. We dated metamorphic mineral growth in the Alpine Schist using a combination of Lu–Hf garnet geochronology and U-Pb zircon petrochronology.
The garnet ages are diachronous, ranging from 97.3 ± 0.3 to 75.4 ± 1.3 Ma. Garnet ages are corroborated by zircon dates acquired using the relatively novel approach of depth profiling using laser-ablation split stream (LASS)-ICP-MS, which enables the analysis of thin and discontinuous metamorphic zircon overgrowths.
Zircon rims that crystallized contemporaneously with garnet show trace element signatures consistent with garnet-stable conditions, while the trace element signatures of younger zircon rims indicate formation either in the presence of melt/fluid or during garnet breakdown.
|Date||Friday, 27 July 2018|
|Time||1:00pm - 2:00pm|
|Location||Benson Common Room (Gn9), Geology Building, 360 Leith Street, Dunedin|