Tuesday, September 23, 2008

"Hotspots" of the South Pacific

A new paper in press:

Pilger, R. H., 2008, Discussion of “Break-up spots: Could the Pacific open as a consequence of plate kinematics”, by Clouard and Gerbault, Earth and Planetary Science Letters, http://dx.doi.org/10.1016/j.epsl.2008.08.005

Abstract: Available isotopic age dates from the Foundation, Austral, Cook, Tokelau, and Gilbert island-seamount chains, combined with kinematic plate-hotspot modelling, indicate that the five chains originated from three distinct melting anomalies (or “hotspots”) well before the onset of postulated intraplate oblique extension. The kinematic pattern produces the observed range of dates due to overlap of the resulting traces. The oblique extension mechanism may have enhanced volcanism, but it cannot be the sole explanation.

The argument in this paper is analogous to that presented in the discussion of another paper: Discussion: “Non-hotspot volcano chains originating from small-scale sublithospheric convection” by Ballmer et al. (2007).