Evolution of flat slabs Flashcards
What is a flat slab?
Where a subducting plate becomes nearly horizontal or glat as it continues to subduct under the overriding plate
What is the first stage?
Initiation of Subduction: The subduction of oceanic lithosphere begins with a typical steep angle, where the subducting plate descends beneath the overriding plate at a steep angle. This is the initial stage of subduction.
What is the second stage?
Steepening of the Subduction Zone: Over time, the subduction zone may experience various processes that lead to the steepening of the angle of subduction. These processes can include the subduction of seamounts or a change in the geometry of the plates.
What is the third stage?
Flattening of the Subducted Plate: As the angle of subduction becomes steeper, the subducted oceanic plate experiences increased resistance from the overriding plate. This resistance can cause the subducted plate to buckle and deform, resulting in the flattening of the slab. The flattening process is thought to be influenced by a combination of factors, including slab pull, mantle flow, and lithospheric buoyancy.
What is the fourth stage?
Segmentation and Tearing: As the flat slab continues to subduct, it may undergo segmentation and tearing. This occurs when the flat slab encounters zones of weakness or changes in the rheology of the subduction zone. The tearing process can lead to the formation of distinct segments within the flat slab.
What is the fifth stage?
Rejuvenation and Reworking: In some cases, the flat slab can undergo rejuvenation and reworking. This occurs when portions of the flat slab detach from the subduction zone and sink deeper into the mantle, while other portions continue to subduct. This process can result in the formation of new subduction zones or changes in the tectonic regime of the region.
