Jeffrey A. Karson, Stephen D. Hurst, Peter Lonsdale; Tectonic rotations of dikes in fast-spread oceanic crust exposed near Hess Deep. Geology ; 20 (8): 685–688. doi: https://doi.org/10.1130/0091-7613(1992)020<0685:TRODIF>2.3.CO;2
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Oceanic crust that initially formed at the fast-spreading (130 mm/yr) East Pacific Rise at ∼1 Ma is exposed in the walls of Hess Deep rift at the northern edge of the Galapagos microplate. Steep fault scarps expose a dismembered vertical sequence of pillow basalts, sheeted diabase dikes and gabbroic rocks. Diabase dikes in these units are dominantly vertical; however, extensive outcrops of steeply to moderatley dipping dikes exist in some places. The nonvertical attitude of the dikes may be the result of tectonic rotations attending sea-floor spreading at the East Pacific Rise or the result of complex rotations of fault blocks during the opening of the Hess Deep rift at ∼0.65 Ma.