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i1052-5173-22-7-4-f03

Figure 3.

(A) Block diagram depicting the effect of lithospheric bending around a vertical axis and the resultant strain field (modified tangential longitudinal strain). Strain ellipses depict arc-parallel shortening in the inner arc and arc-parallel stretching in the outer arc. Note the different behavior of the mantle lithosphere in the inner and outer arcs and the increase in thickness of mantle lithosphere below the inner arc and thinning below the outer arc. (B) Snapshot illustration of arc development starting with a linear belt resulting from a Gondwana–Laurentia collision. (C) Second snapshot illustrating oroclinal bending, which causes lithospheric stretching in the outer arc and thickening beneath the inner arc (Gutiérrez-Alonso et al., 2004). (D) The final stage of oroclinal bending, depicting delamination and collapse of thickened lithospheric root beneath the inner arc, replacement of sinking lithosphere by upwelling asthenospheric mantle, and associated magmatism in the inner and outer arc regions. (E) Two tomographic views of the analogue modeled mantle lithosphere geometry after buckling around a vertical axis where the lithospheric root is developed under the inner arc (top—frontal view from the concave part of the model; bottom—view from below); 3-D coordinate axes given. (F) Tomographic 3-D image of the delaminated lithospheric root obtained with analogue modeling; 3-D coordinate axes given.

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