Current Research projects

The Oceanic Nazca Plate

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

This image is a screenshot of a Pplates reconstruction movie at 7 Ma, illustrating Andean porphyry deposit formation.

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.

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Reconstructing the evolution of the European Alps in 4D

A Tectonic Reconstruction Project by Clemens Augenstein, PhD Candidate

The Alpine-Carpathian Arc.

Palaeogeographic reconstructions of the Alpine-Carpathian Arc have until now been done largely by rotating and translating rigid 2D components. These reconstructions were usually complemented by cross-sections through a few areas believed to play a key role in the Alpine evolution. This simple approach, however, accounts for little of the vast amount of data available for the Alpine-Carpathian Arc. A first step will be the construction of a 3D model of the present-day slab geometry in the Alpine region from existing tomographic data (see The VIrtual Earth). This will be the initial point for a 4D reconstruction that will eventually lead back to Early Jurassic times. An important role for the timing of events in this reconstruction will be the integration of dates gained from major shear-zone outcrops in the Alpine Arc.

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Revising the history of motion of the Indian Plate (0-100 Ma) and reconstructing the 4D evolution of the Himalaya

A Tectonic Reconstruction Project by Lloyd White, PhD Candidate

This image is a screenshot from the Pplates reconstruction software showing the motion history of the Indian plate from 0-84 Ma from the data published by Dewey et al. (1989). This image also shows the Tracking Points feature of Pplates.

A number of 2D rigid plate reconstructions have been made to model the history of convergence between the Indian and Eurasian plates. Most of these models have attempted to determine the timing of "the collision" between India and Eurasia on the basis of a reduction in the northward velocity of the Indian plate at certain points in time. However, many workers now recognize that the Himalaya developed due to a number of accretion events, and the idea of a discrete "collision" is unfounded. The first aim of this project is to review the motion history of the Indian plate, as this has not been revised properly since the late 1980's (Dewey et al. 1989).

Almost every publication dealing with the Himalaya proposes a different tectonic model/architecture for the historical development of the Himalaya. Yet, very little work has been completed to characterize the subducted slabs below the Himalaya in three dimensions. Therefore the second aim of this project is to use existing tomographic data (see The Virtual Earth). The final phase of this project will be to build a deformable plate reconstruction of the Indian and Eurasian plates from 100 Ma to present.

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