Role of Avalonia in the development of tectonic paradigms
Published:November 11, 2019
J. Brendan Murphy, R. Damian Nance, J. Duncan Keppie, Jaroslav Dostal, 2019. "Role of Avalonia in the development of tectonic paradigms", Fifty Years of the Wilson Cycle Concept in Plate Tectonics, R. W. Wilson, G. A. Houseman, K. J. W. McCaffrey, A. G. Doré, S. J. H. Buiter
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The geological evolution of Avalonia was fundamental to the first application of plate tectonic principles to the pre-Mesozoic world. Four tectonic phases have now been identified. The oldest phase (760–660 Ma) produced a series of oceanic arcs, some possibly underlain by thin slivers of Baltica crust, which accreted to the northern margin of Gondwana between 670 and 650 Ma. Their accretion to Gondwana may be geodynamically related to the break-up of Rodinia. After accretion, subduction zones stepped outboard, producing the main phase (640–570 Ma) of arc-related magmatism and basin formation that was coeval with the amalgamation of Gondwana. Arc magmatism terminated diachronously between 600 and 540 Ma by the propagation of a San Andreas style transform fault, followed by the Early Paleozoic platformal succession used by Wilson to define the eastern flank of the proto-Atlantic (Iapetus) Ocean. This implies the ocean outboard from the northern Gondwanan margin survived into the Cambrian. Avalonia is one of several terranes distributed obliquely with respect to the adjacent cratonic provinces of Gondwana and Baltica, implying that these terranes evolved on different cratonic basements. As a result, their ages and differing isotopic signatures can be used to reconstruct their respective locations along the ancient continental margin.
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Fifty Years of the Wilson Cycle Concept in Plate Tectonics
CONTAINS OPEN ACCESS
Fifty years ago, Tuzo Wilson published his paper asking ‘Did the Atlantic close and then re-open?’. This led to the ‘Wilson Cycle’ concept in which the repeated opening and closing of ocean basins along old orogenic belts is a key process in the assembly and breakup of supercontinents. The Wilson Cycle underlies much of what we know about the geological evolution of the Earth and its lithosphere, and will no doubt continue to be developed as we gain more understanding of the physical processes that control mantle convection, plate tectonics, and as more data become available from currently less accessible regions.
This volume includes both thematic and review papers covering various aspects of the Wilson Cycle concept. Thematic sections include: (1) the Classic Wilson v. Supercontinent Cycles, (2) Mantle Dynamics in the Wilson Cycle, (3) Tectonic Inheritance in the Lithosphere, (4) Revisiting Tuzo's question on the Atlantic, (5) Opening and Closing of Oceans, and (6) Cratonic Basins and their place in the Wilson Cycle.