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Diagram of a cross-section of the Patagonia slab window. The Nazca plate and Antarctic plate are colliding with the South American plate at the Chile Ridge. [1]In geology, a slab window is a gap that forms in a subducted oceanic plate when a mid-ocean ridge meets with a subduction zone and plate divergence at the ridge and convergence at the subduction zone continue, causing the ridge to be ...
The figure is a schematic diagram depicting a subduction zone. The subduction slab on the right enters the mantle with a varying temperature gradient while importing water in a downward motion. A model of the subducting Farallon slab under North America. In geology, the slab is a significant constituent of subduction zones. [1]
Slab suction is weaker than slab pull, which is the strongest of the driving forces. When measuring the forces of these two mechanisms, slab pull in subducting plate boundaries for upper mantle slabs is 1.9 × 10^21 N. [ clarification needed ] In comparison slab suction in the upper and lower mantle totaled 1.6 × 10^21 N. [ 3 ]
The slab window generated by the Chile Ridge's subduction passed at the latitudes of Pali-Aike about 4.5 million years ago; volcanic activity commenced soon afterwards but the time difference was enough for any subduction-influenced mantle to be displaced by fresher mantle moving through the window, which is the main source of the Pali-Aike ...
The source of the material which flows into the slab window is a matter of debate, specifically whether it is derived directly from the underlying mantle, or from the mantle wedge to the east. The chemistry of erupted basalts associated with the MTJ are typical of mantle wedge–derived melts, characterized by enrichment in the large-ion ...
A tectonic window, or fenster (lit. "window" in German), is a geologic structure formed by erosion or normal faulting on a thrust system. In such a system the rock mass ( hanging wall block ) that has been transported by movement along the thrust is called a nappe .
An oceanic trench is a type of convergent boundary at which two oceanic lithospheric slabs meet; the older (and therefore denser) of these slabs flexes and subducts beneath the other slab. Oceanic lithosphere moves into trenches at a global rate of about a tenth of a square meter per second.
Madsen et al. (2006) showed that most of the Eocene and subsequent magmatism from Alaska to Oregon "is explainable in terms of ridge subduction and slab window tectonics". [91] That is, a slab window — and a single subducted ridge can give rise to multiple slab windows — can provide adequate magmatism without having to invoke a hotspot ...