Correct option is D
Introduction
- Accretionary prisms (also called accretionary wedges) are wedge-shaped masses of sediment that accumulate at convergent plate boundaries.
- They form through the process of subduction, where one tectonic plate descends beneath another.
- As the oceanic plate subducts, sediments are scraped off and accumulate, forming a distinctive geological structure crucial to understanding mountain building and continental growth.
Information Booster:
- Ocean-Continent Convergence Boundary
- Formation Process: Denser oceanic plate subducts beneath lighter continental plate
- Sediments on oceanic floor and trench are scraped off (like a bulldozer)
- Material accumulates and compresses into wedge shape
- Wedge-shaped sedimentary mass
- Composed of marine sediments, oceanic crust fragments, and scraped material
- Intensely folded and faulted (thrust faults dominate)
- Grows landward over time (oceanward dipping)
- Width: tens to hundreds of kilometers
Additional knowledge:
- Transform Fault Boundary
- Plates slide horizontally past each other
- No subduction or compression
- Strike-slip faulting dominates
- Continent-Continent Convergence
- Both plates have similar low density (no subduction)
- Results in mountain building (orogeny)
- Fold mountains with intense deformation
- Crustal thickening rather than scraping