Global plate reorganization events (GPREs) can have profound impact on plate velocities, climate and the biotic cycle but the timing and triggers for GPREs remain debated. The timing and causes of the mid-Cretaceous GPRE, one of only two GPREs since the breakup of Pangea, remains poorly constrained because it occurred during the Cretaceous Normal Superchron. Here, we provide a new plagioclase ⁴⁰Ar/³⁹Ar age of Ma (2σ) at DSDP site 256 along the world's clearest curved fracture zones in the Wharton Basin, off NW Australia. Using Monte Carlo simulations, we compute that the mid-Cretaceous GPRE commenced at Ma (95% confidence). The mid-Cretaceous GPRE was associated with a significant plate deceleration (minimum ∼26%), similar to the Eocene GPRE, implying that this process is fundamental to plate reconfigurations. We propose that the mid-Cretaceous GPRE was caused by slab-breakoff and cessation of the south-dipping subduction zone in the Mesotethys Ocean at ca. 111 Ma. Ultimately, we posit that subduction zone initiations and cessations are the primary triggers for both post-Pangean GPREs and that top-down processes may be the fundamental drivers for GPREs.

Item Type:	Refereed Article
Keywords:	plate tectonics, 40Ar/39Ar geochronology, Wharton Basin, eastern Gondwana, Neotethys, subduction, slab pull
Research Division:	Earth Sciences
Research Group:	Geology
Research Field:	Marine geoscience
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the earth sciences
UTAS Author:	Whittaker, JM (Associate Professor Jo Whittaker)
ID Code:	137078
Year Published:	2020
Web of Science® Times Cited:	16
Deposited By:	Oceans and Cryosphere
Deposited On:	2020-01-30
Last Modified:	2022-08-23
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