Gravity-driven large-scale deformation system in the Tumbes-Guayaquil forearc basin, Northern Andes (Northern Peru-Southern Ecuador)

The offshore Tumbes-Guayaquil forearc basin in the accretionary prism of Northern Peru-Southern Ecuador shows evidence gravity-driven large-scale deformation systems active during Late Neogene-Quaternary period. Subsurface data and construction eight structural cross-sections show that ∼8 km-thick Oligocene-Quaternary sedimentary infill is detached seaward completely decoupled from underlying inner systems. Corvina décollement Tumbes Posorja Guayaquil constitute two thin-skinned gravity tectonic associated with kilometer-scale, updip “raft” extensional structures paired downdip fold-thrust (Barracuda Domito thrust systems). Although many previous studies have described stratigraphic architecture basin, no model explicitly accounts for this anomalous tectonics. We propose style, more commonly observed passive continental margins, primarily controlled by combination tectonostratigraphic features, including crustal-scale transtensional related to oblique convergence along Andean margin, basal slope tilting, strong sediment accumulation, presence overpressured shales.