Tertiary faulting and pseudotachylytes in the East Greenland volcanic rifted margin: Seismogenic faulting during magmatic construction

Abstract

Volcanic rifted margins have voluminous magmatic constructions at continent-ocean transitions including thick sequences of flood basalts, dike swarms, and mafic plutons developed in crustal-scale flexures. In the Tertiary East Greenland volcanic rifted margin, upper crustal dilation and flexure were accommodated by extensive faulting, locally pervasive cataclastic deformation, and pseudotachylyte generation. The widespread distribution and large volumes of pseudotachylyte suggest that regional seismogenic faulting was vigorous during rapid crustal subsidence, dike intrusion, and the start of sea-floor spreading.