Neoproterozoic juvenile crust development in the peri-Rodinian ocean: Implications for Grenvillian orogenesis
Published:January 01, 2004
J. Brendan Murphy, Jaroslav Dostal, R. Damian Nance, J. Duncan Keppie, 2004. "Neoproterozoic juvenile crust development in the peri-Rodinian ocean: Implications for Grenvillian orogenesis", Proterozoic Tectonic Evolution of the Grenville Orogen in North America, Richard P. Tollo, James McLelland, Louise Corriveau, Mervin J. Bartholomew
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The supercontinent Rodinia is thought to have been formed by 1.2 to 1.0 Ga continent-continent collisions and to have dispersed between 0.75 and 0.6 Ga. The existence of Rodinia implies the presence of a Panthalassalike peri-Rodinian ocean between ca. 1.0 and 0.75 Ga within which juvenile crust developed. Although the vast majority of this crust was later subducted, vestiges are preserved in terranes that accreted to the leading edges of the dispersing continents following the breakup of Rodinia. These terranes are recognized by their ca. 1.2 to 0.75 Ga Sm-Nd depleted mantle (TDM) model ages, coeval with the life of Rodinia. They include ca. 0.9 to 0.8 Ga ophiolites and ensimatic arc complexes, and ca. 0.8 to 0.6 Ga recycled mafic to fel-sic arc complexes. Formed within the peri-Rodinian ocean, the terranes were accreted to their respective continental margins in the Late Neoproterozoic. For orogens in which subduction culminated in Late Neoproterozoic continental collision (e.g., the Southern Yangste margin, Brasiliano, and Trans-Saharan orogens), vestiges of peri-Rodinian crust became cratonized within the suture zones between the colliding cratons. In accretionary orogens, in which subduction was not terminated by continental collision (e.g., the Arabian Shield and peri-Gondwana orogens), the terranes were subsequently involved in Paleozoic orogenesis. More generally, crustal formation in Panthalassa-type oceans and the subsequent recycling of this crust can be recognized by Sm-Nd TDM model ages that overlap the life span of the supercontinent.