| |
Dr Julian Pearce’s presentation is a guest lecture presented by the Centre for Exploration Targeting.
Even in recent, fresh lavas and with a full battery of element and isotope tools at our disposal, there can be debate over whether arc-like geochemical signatures result from active subduction, an older, inherited subduction component in the lithosphere, or crustal contamination. In the Archean, metamorphism, deformation, a hotter thermal regime and potential non-uniformitarian tectonic scenarios make the recognition of arc lavas particularly problematic. This talk will examine ehwther geochemical fingerprinting can reliably be applied to Archean volcanic rocks – and hence whether subduction-like signatures do provide evidence for Early Earth plate tectonics. It will conclude by addressing the recently-debated hypothesis for a subduction initiation origin for the volcanic ‘sequence’ in the Earth’s oldest volcanic rocks, from Nuvvuagittuq in northern Canada (see papers by Turner et al. and Pearce in Geology, February 2014).
Attendees are invited to join CET staff and students for refreshments in the Resource Room, Robert Street Building.
