Slumping and a sandbar deposit at the Cretaceous-Tertiary boundary in the El Tecolote section (northeastern Mexico): An impact-induced sediment gravity flow

Slumps affecting uppermost Mendez Formation marls, as well as the spherulit ic layer and basal part of the sandy deposits of the Cretaceous-Tertiary (K -T) boundary elastic unit, are described at the new K-T El Tecolote section (northeastern Mexico). These K-T elastic deposits represent sedimentation at middle-bathyal water depths in channel and nonchannel or levee areas of reworked materials coming from environments ranging from outer shelf to sha llower slope via a unidirectional, high- to low-density turbidite flow. We emphasize the development and accretion of a lateral bar in a channel area from a surging low-density turbidity current and under a high-flow regime. The slumps discovered on land and the sedimentary processes of the K-T elas tic unit reflect destabilization and collapse of the continental margin, su pport the mechanism of gravity flows in the deep sea, and represent importa nt and extensive evidence for the impact effects in the Gulf of Mexico trig gered by the Chicxulub event.