PhD project on intraplate volcanism, Dunedin Volcano, NZ:
Low-volume intraplate volcanism has been common on Zealandia (NZ) through the Mesozoic and Cenozoic, and cannot be explained by classic tectonic drivers such as subduction or rifting at plate boundaries, nor by major mantle plumes. Varying levels of crustal heat flow and mantle helium are associated with on-land intraplate volcanic sites of Zealandia, with typical values averaging 60 mW m-2 and 20% mantle helium. The Miocene Dunedin Volcano, despite having been extinct since 10 Ma, is characterised by high heat flow (c. 90 mW m-2) and high mantle helium (c. 84%). It is an intriguing target for analysis of processes which drive intraplate volcanism, given that the high heat flow and mantle helium values also suggest the possibility that new volcanism could be initiated adjacent to New Zealand’s 7th most populous city. This project will test the hypothesis that there are common melting and ascent processes which have produced intraplate volcanism in diverse settings in Zealandia, with decompression melting playing the leading role. Other drivers are inferred, both common across the spectrum of intraplate volcanism and specific to individual centres. Dunedin Volcano is the central focus of study, representing major intraplate centres in New Zealand. Specific methods will include single crystal argon-argon and uranium-lead dating including dating of growth layers within individual crystals. Volcano growth, development, paleoenvironmental conditions and crustal structure will be determined using modern physical volcanological, geochemical and isotopic techniques. The internal, 3-dimensional architecture of Dunedin Volcano will be determined using geophysical imaging of the crustal and upper mantle palaeo-magmatic system by magnetotelluric (MT) methods (like a MRI scan), informed by existing magnetic and gravity data. A 4D (3D+time) model of the interior of Dunedin Volcano will be produced, a first for an intraplate volcano in New Zealand, to determine the relative tectonic-magmatic influences on intraplate volcanism. A globally applicable model for intraplate volcanism will also be developed.
The project will develop and utilize skills in computational modelling, thermodynamics, and volcanic processes. Techniques developed and employed during this study will have applications across volcanology, and also for other geofluids and engineering applications.
We seek applications from high-performing Masters and BSc(honours) students able to compete successfully for a University of Otago doctoral scholarship (http://www.otago.ac.nz/study/
Send inquiries to james.white@xxxxxxxxxxx
Volcano Listserv is a collaborative venture among Arizona State University (ASU), Portland State University (PSU), the Global Volcanism Program (GVP) of the Smithsonian Institution's National Museum of Natural History, and the International Association for Volcanology and Chemistry of the Earth's Interior (IAVCEI).
ASU - http://www.asu.edu/ PSU - http://pdx.edu/ GVP - http://www.volcano.si.edu/ IAVCEI - http://www.iavcei.org/
To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxx.
To contribute to the volcano list, send your message to: volcano@xxxxxxx. Please do not send attachments.
==============================================================
