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A Tectonic Reconstruction Project by Tomas O'Kane, PhD Candidate

We have been developing rigid plate animations illustrating the formation of porphyry Cu-Au and gold deposit formation throughout the last 25 Ma. The oceanic Nazca Plate is currently subducting under the South American continental lithosphere, with the white space between the plates representing subducted oceanic lithosphere. Relative plate motions have been calculated (Eagles, 2007; Rosenbaum et al, 2005), and applied using the South American Plate as a reference object (kept stationary), with the relative motion applied to the Nazca plate. The NOAA topography database is incorporated into the animations in order to observe the relationship between the Andean margin and the various topographic features present on the Nazca plate.

A detailed analysis of the dynamics exhibited by the Nazca slab is being undertaken with a focus placed on analysing its tectonic influence upon the overriding South American lithosphere, and thus mineralization, and an emphasis on examining slab structure, specifically slab tearing. Using SRTM topography dataset of a much greater resolution will enable an analysis of topographic features and ore deposit formation through time to be undertaken in detail. The deposit age data was collated from Gideon Rosenbaum (pers. Comm.) and open-source datasets, however more deposits are to be added, and age data refined as additional datasets are sourced. This data is crucial to resolving potential links between structure-time-deposit formation.