Continental Growth and Recycling in Convergent Orogens with Large Turbidite Fans on Oceanic Crust

摘要: Convergent plate margins where large turbidite fans with slivers of oceanic basement are accreted to continents represent important sites continental crustal growth and recycling. Crust in these settings is dominated by an upper layer recycled arc detritus (turbidites) underlain a tectonically imbricated crust and/or thinned crust. When converted lower it represents juvenile addition the budget. This two-tiered often same thickness as average isostatically balanced near sea level. The Paleozoic Lachlan Orogen eastern Australia archetypical example tubidite-dominated accretionary orogeny. Neoproterozoic-Cambrian Damaran SW Africa similar except that was incorporated into Gondwana via continent-continent collision. Mesozoic Rangitatan New Zealand illustrates transition convergent margin from Lachlan-type more typical wedge type orogen. spatial temporal variations deformation, metamorphism, magmatism across orogens illustrate how volumes their relict eventually become stable timing deformation metamorphism recorded rocks reflects thickening phase, whereas post-tectonic constrains chemical maturation cratonization. Cratonization fostered because turbidites fertile sources for felsic magmatism. Recognition Proterozoic Archean evaluation models, particularly those based on detrital zircon age patterns, accretion or mafic underplating does not readily result voluminous zircon-bearing magmas at time accretion. only produces significant when if partially melts, which may occur long after