However, the large, left lateral, Ulakhan fault has also been suggested as a candidate plate boundary. The plate boundary between Okhotsk and North America has been suggested to be diffuse, based on widely scattered minor seismicity. Extrusion tectonics along multiple, large strike-slip faults within the Okhotsk plate itself have been suggested to allow the escape of material away from the apex of Eurasia-North America. Lying between the North American and Eurasian plates, its northwestern corner would appear to be undergoing compression in a scissors motion between the two bounding plates.
The Okhotsk plate has been postulated based on a combination of GPS geodetic inversions (REVEL1), seimsicity, geologic and lineament data. Key Points Contraction along divergent plate boundaries results from dike emplacementContraction generates extensional structures along divergent plate boundariesSurface deformation along divergent plate boundaries may be magma inducedĪ Possible Differentially Shortened Strike-slip Plate Boundary: the Okhotsk Plate Example. Our results suggest that contraction is a direct product of magma emplacement along divergent plate boundaries, at various scales, marking a precise evolutionary stage and initiating part of the extensional structures (extension fractures and normal faults). Multiple dike injection induces subsidence above and uplift to the sides of the dikes the transition in between is accommodated by reverse faults and subsequent peripheral inward dipping normal faults. Our experiments suggest that these structures result from dike emplacement. Contraction is found at the base of the tilted hanging wall of dilational normal faults, balancing part of their extension. Here we present evidence of contraction along the axis of the oceanic ridge of Iceland and the continental Main Ethiopian Rift. The axis of divergent plate boundaries shows extension fractures and normal faults at the surface.
Dike-induced contraction along oceanic and continental divergent plate boundaries
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