Accretionary orogens through Earth history

Abstract

Accretionary orogens form at intraoceanic and continental margin convergent plate boundaries. They include the supra-subduction zone forearc, magmatic arc and back-arc components. Accretionary orogens can be grouped into retreating and advancing types, based on their kinematic framework and resulting geological character. Retreating orogens (e.g. modern western Pacific) are undergoing long-term extension in response to the site of subduction of the lower plate retreating with respect to the overriding plate and are characterized by back-arc basins. Advancing orogens (e.g. Andes) develop in an environment in which the overriding plate is advancing towards the downgoing plate, resulting in the development of foreland fold and thrust belts and crustal thickening. Cratonization of accretionary orogens occurs during continuing plate convergence and requires transient coupling across the plate boundary with strain concentrated in zones of mechanical and thermal weakening such as the magmatic arc and back-arc region. Potential driving mechanisms for coupling include accretion of buoyant lithosphere (terrane accretion), flat-slab subduction, and rapid absolute upper plate motion overriding the downgoing plate. Accretionary orogens have been active throughout Earth history, extending back until at least 3.2 Ga, and potentially earlier, and provide an important constraint on the initiation of horizontal motion of lithospheric plates on Earth. They have been responsible for major growth of the continental lithosphere through the addition of juvenile magmatic products but are also major sites of consumption and reworking of continental crust through time, through sediment subduction and subduction erosion. It is probable that the rates of crustal growth and destruction are roughly equal, implying that net growth since the Archaean is effectively zero.Classic models of orogens involve a Wilson cycle of ocean opening and closing with orogenesis related to continent-continent collision. These imply that mountain building occurs at the end of a cycle of ocean opening and closing, and marks the termination of subduction, and that the mountain belt should occupy an internal location within an assembled continent (supercontinent). The modern Alpine -Himalayan chain exemplifies the features of this model, lying between the Eurasian and colliding African and Indian plates (Fig.

Geophysical perspective on the structural interference zone along the Neoproterozoic Brasília and Ribeira fold belts in West Gondwana

“…This contrasts to the observation that thrust systems are common in orogens involving shallower crust conditions (thin-skinned tectonics) as observed on Brasilia Fold Belt further north from study area (Simões 1995, Strieder & Suita 1999. Collision tectonics models supports late-colisional continental block adjustment in large-scale shear belts, overprinting prior structural grain (Cawood et al 2009, Gerya 2014, Jamieson & Beaumont 2013.…”

“…However, present models on mantle thermal evolution and mass transfer points out to a dynamic scenario from early Earth to nowadays tectonics with different evolution of collisional systems along time, markedly post-Proterozoic orogens (Cawood et al 2009, Abbott et al 2013, Gerya 2014, Jamieson & Beaumont 2013, Kamber 2015. Lower-and upper-crust sections juxtaposition by thrust systems supports its evolution by thick-skinned tectonics style (Coward 1983).…”

Petrology and geochemistry of meta-ultramafic rocks in the Paleozoic Granjeno Schist, northeastern Mexico: Remnants of Pangaea ocean floor

“…During Late Carboniferous and early Permian times Gondwana and Laurentia collided to form the supercontinent Pangaea [31,32] separating several small terranes from Gondwana and accreted to Laurentia [33][34][35]. Remnants of the late Paleozoic Rheic Ocean closure and consequent collision between Laurentia and Gondwana are scarce, but not absent in Mexico.…”

Basin formation by thermal subsidence of accretionary orogens

“…Such crust inherits the thin mantle lithosphere of many of its constituent building blocks (island arcs, accretionary wedges and young oceanic crust), and as this cools and thickens following tectonic assembly it causes subsidence as an isostatic response. However, it has not yet been proven if the process is an inherent property of juvenile crust generated by accretionary orogeny (Cawood et al, 2009), and therefore generally applicable. This paper aims to test this subsidence mechanism by looking at an overview of the subsidence patterns from a number of regions of accretionary crust.…”

“…Ultimately, such accretionary orogens may be the principal sites for net crustal growth, and have operated as such back into the Archaean (Cawood et al, 2009). The ages of accretion for the continental crust are shown in Fig.…”