sedimentary basins
Basin classification: Sedimentary basins are regional depressions where sediments, eroded particles from continents and transported by river systems and run-off water, accumulate. Mechanism that can create surface depression are:
• Extension driven by plate boundary forces (passive rifting).
• Thermal lithospheric cooling and contraction - thickens mantle lithosphere
• Crustal extension driven by buoyancy of relatively thin mantle lithosphere (active rifting) (6 and 2 are competing processes)
• Metamorphic reactions (up to ~1km of additional subs.)
• Flexure (foreland basins)
• Dynamic topography driven by convecting mantle
The physical mechanisms forming these depressions can be divided in 3 categories, each responsible for a particular type of sedimentary basin:
(1) Extension and faulting (rift Basins, continental margins)
(2) Flexure of the lithosphere (flexural basin in orogenic forelands, thermal sag flexural basins)
(3) Dynamic topography above mantle downwelling