Research
My research focuses on understanding the tectonic and geochemical evolution of Earth’s crust, particularly within orogenic systems. I combine field research, metamorphic and igneous petrology, elemental and isotope geochemistry, and geochronology to understand a range of geologic processes, from large-scale tectonic events, to micro-scale mineral properties. Common to all of my research projects is the use of combined isotopic and elemental analysis by ICP-MS (petrochronology).
Linking zircon age to metamorphic stage using laser ablation split-stream depth-profiling and Lu-Hf garnet geochronology
Depth profiling is becoming a popular method for extracting information on the (re)crystallization events recorded in thin metamorphic zircon rims. However, the acquisition of geologically meaningful ages via depth profiling has been hindered by variation in the presence and/or thickness of zircon rims. Laser pits that sample rim domains of irregular thickness can result in mixing of distinct rim and core domains, producing geologically meaningless data. My most recent research project has focused on establishing analytical protocols for laser ablation split-stream (LASS)-ICP-MS depth-profiling of thin zircon rims, tailored to the application of this method as a broad surveying tool for large sample suites. By adopting an intensive sampling strategy, we demonstrate the ability of LASS-ICP-MS depth-profiling to resolve multiple short-duration (re)crystallization events, with corresponding chemical signatures that can be linked to different metamorphic stages within the Alpine Schist, spanning prograde garnet-stable conditions to post-peak decompression and fluid/melt influx. This study validates the potential of this high spatial resolution method as a petrochronologic tool.
See EGU poster
See EGU poster
Lu-Hf garnet geochronology of the Alpine Schist accretionary complex: constraining tectonic processes during the late stages of Gondwana breakup
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Timescales of fluid-assisted crustal anatexis during regional lithospheric extension in Zealandia using monazite petrochronology
Anatectic pegmatites exposed in the Mataketake Range of the Southern Alps represent partial melts of the Alpine Schist. This study investigates the timing and duration of partial melting in the Southern Alps through laser ablation split-stream (LASS) ICP-MS petrochronology of monazite, zircon and xenotime. Results indicate that fluid assisted crustal anatexis occurred from 81.5 ± 1.4 Ma to 50.5 ± 0.3 Ma in the metamorphosed accretionary complex of Zealandia. This prolonged period of partial melting is contemporaneous with rifting of Zealandia from East Gondwana from 83 – 52 Ma. Dehydration of the subducted Hikurangi Plateau LIP, introduction of meteoric water through distributed shear zones, or conductive heating through a thinned lithosphere could be invoked to explain this protracted period of partial melting.
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Geochronology and geochemistry of lamprophyre differentiates from the Alpine Dike Swarm, New Zealand
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