Rapid change in drift of the Australian plate records collision with Ontong Java plateau

Knesel, K. M., Cohen, B. E. , Vasconcelos, P. M. and Thiede, D. S. (2008) Rapid change in drift of the Australian plate records collision with Ontong Java plateau. Nature, 454(7205), pp. 754-757. (doi: 10.1038/nature07138) (PMID:18685705)

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Abstract

The subduction of oceanic plateaux, which contain extraordinarily thick basaltic crust and are the marine counterparts of continental flood-basalt provinces, is an important factor in many current models of plate motion1, 2, 3, 4 and provides a potential mechanism for triggering plate reorganization5. To evaluate such models, it is essential to decipher the history of the collision between the largest and thickest of the world's oceanic plateaux, the Ontong Java plateau, and the Australian plate, but this has been hindered by poor constraints for the arrival of the plateau at the Melanesian trench. Here we present 40Ar–39Ar geochronological data on hotspot volcanoes in eastern Australian that reveal a strong link between collision of the Greenland-sized Ontong Java plateau with the Melanesian arc and motion of the Australian plate. The new ages define a short-lived period of reduced northward plate motion between 26 and 23 Myr ago, coincident with an eastward offset in the contemporaneous tracks of seamount chains in the Tasman Sea east of Australia. These features record a brief westward deflection of the Australian plate as the plateau entered and choked the Melanesian trench 26 Myr ago. From 23 Myr ago, Australia returned to a rapid northerly trajectory at roughly the same time that southwest-directed subduction began along the Trobriand trough6. The timing and brevity of this collisional event correlate well with offsets in hotspot seamount tracks on the Pacific plate, including the archetypal Hawaiian chain7, and thus provide strong evidence that immense oceanic plateaux, like the Ontong Java, can contribute to initiating rapid change in plate boundaries and motions on a global scale.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cohen, Dr Benjamin
Authors: Knesel, K. M., Cohen, B. E., Vasconcelos, P. M., and Thiede, D. S.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:Nature
Publisher:Nature Publishing Group
ISSN:0028-0836
ISSN (Online):1476-4687

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