Definition of accretionary prism in English:

accretionary prism

(also accretionary wedge)


  • A mass of sedimentary material scraped off a region of oceanic crust during subduction and piled up at the edge of a continental crustal plate.

    • ‘This style of flow is not unexpected at deep levels of an accretionary prism like the Otago Schist that is being thickened by underplating from below.’
    • ‘In accretionary prism models, the fact that the sediments are unlithified during deformation and burial indicates that accretion occurred soon after deposition.’
    • ‘Around both zones accretionary wedges are indications of Cretaceous subduction.’
    • ‘This assemblage is interpreted as the accretionary prism of an active continental margin.’
    • ‘Episodes of differential uplift are attributed to active subcretion building culminations above blind imbricate thrusts deep in the accretionary prism beneath the coast.’
    • ‘The disposition of these three neighbouring units probably corresponds to their original relations in the growing accretionary wedge.’
    • ‘In summary, we interpret Unit II as a fragment of a volcanic seamount incorporated into an Early Palaeozoic accretionary prism.’
    • ‘In ancient accretionary wedges elsewhere, they typically overlie chert sequences and are commonly interpreted to have accumulated upon oceanic crust close to a convergent margin.’
    • ‘Collectively these objectives will comprise a comprehensive effort to delineate the mechanics of fluid migration and dewatering activity in the Costa Rica accretionary prism.’
    • ‘It seems unlikely that an ophiolite fragment 300 km long would remain intact and unmixed with the rest of the rocks in an accretionary wedge.’
    • ‘Work on modern accretionary prisms and analogue experiments have recently emphasized the role of seismic activity in the generation of similar vein arrays.’
    • ‘The complexes were stacked during the Devonian in an accretionary wedge to the west or NW of the Rheic oceanic basin.’
    • ‘The Dzag schists to the north of the ophiolite zone have previously been interpreted as part of an accretionary wedge.’
    • ‘There is a continuing loss of some sediment into the mantle at subduction zones, although the ‘conveyor-belt’ system of plate tectonics ensures that most sediment is added to the accretionary wedge of the overriding plate.’
    • ‘A maximum age is indicated by the Cambrian Akaz seamount in an accretionary prism, the presence of which implies the existence of a trench adjacent to the arc.’
    • ‘The most widely accepted view is that of an accretionary prism developed above an active subduction zone.’
    • ‘This higher mobility is probably due to an extremely thin crust at the advancing edge of the overriding plate, easily affected by the growth or erosion of the accretionary wedge.’
    • ‘The Oman Fault separates the Zagros fold and thrust belt from the Makran accretionary wedge in the east.’
    • ‘Although it is currently interpreted as an accretionary prism complex, the exact depositional setting remains unclear.’
    • ‘A seamount capped by limestone was incorporated into the accretionary prism north of the arc in Cambrian-Early Ordovician time.’