Geodynamic Reconstructions of the Australides—2: Mesozoic–Cainozoic

Abstract

The present work, derived from a full global geodynamic reconstruction model over 600 Ma and based on a large database, focuses herein on the interaction between the Pacific, Australian and Antarctic plates since 200 Ma, and proposes integrated solutions for a coherent, physically consistent scenario. The evolution of the Australia-Antarctica-West Pacific plate system is dependent on the Gondwana fit chosen for the reconstruction. Our fit, as defined for the latest Triassic, implies an original scenario for the evolution of the region, in particular for the "early" opening history of the Tasman Sea. The interaction with the Pacific, moreover, is characterised by many magmatic arc migrations and ocean openings, which are stopped by arc-arc collision, arc-spreading axis collision, or arc-oceanic plateau collision, and subduction reversals. Mid-Pacific oceanic plateaus created in the model are much wider than they are on present-day maps, and although they were subducted to a large extent, they were able to stop subduction. We also suggest that adduction processes (i.e., re-emergence of subducted material) may have played an important role, in particular along the plate limit now represented by the Alpine Fault in New Zealand.

Record of massive upwellings from the Pacific large low shear velocity province

“…Altaids; Vérard, et al 78,. Global Euler poles distribution; Vérard and Stampfli79, Australides; and Stampfli, et al 80,. Pangea.…”

Geodynamic Reconstructions of the Australides—1: Palaeozoic

“…The retained solutions for the "Gondwana best-fit" are given in [4]. The position of GDUs at 200 Ma has influence on our starting configuration at 600 Ma.…”

“…The present work aims to reappraise the geodynamic evolution of the East Australia-East Antarctica-Tasman Sea-New Zealand-proto-Pacific region for the Palaeozoic-and for the Mesozoic-Cainozoic in a companion paper [4]-from a full global reconstruction model. The model is OPEN ACCESS merely a model, but uses strict plate tectonic rules and physically coherent hypotheses, deeply rooted on geological data.…”

Back-Arc Spreading Centers and Superfast Subduction: The Case of the Northern Lau Basin (SW Pacific Ocean)

“…This setup was chosen due to the continental nature of some microplate remnants [37,40,43]. The upper continental plate has a thickness of 100 km, whereas the lower oceanic plate has an age of 100 Ma [68][69][70]. The model run represents the evolution of the Tonga subduction zone (Lau-Basin) during the last 1 Ma.…”