Abstract - The Neogene Tabernas Basin, SE Spain, provides important evidence at outcrop for the interplay between tectonic deformation of
the sea floor, slope instability and turbidity current behaviour. Dextral-oblique strike-slip faults and associated folds propagated
along the basin axis to deform the palaeo-sea floor, creating structurally-controlled depressions in which turbidity currents were
trapped and ponded. EW-trending syn-depositional faults define a narrow sub-basin that subsided asymmetrically as a negative
flower structure. The sub-basin contains an expanded succession (>300m of ponded turbidite sheets, debrites and slumps) along its
northern margin flanked by the principal fault strand defined by a wide zone of sheared and calcite-veined marl. A narrower fault
zone with a smaller displacement marks the southern margin of the sub-basin and the fill close to it is thin with internal
discordances, evidence of local failure and southward thinning of sandstone sheets. Both northern and southern faults ‘died’ at the
same stratigraphic level and were overstepped by basin floor turbidites showing evidence of weaker and longer-range
topographic confinement. As turbidites healed and aggraded out of the sub-basin to progressively onlap the southern margin of the
basin, major gravity failures occurred emplacing thick (>100m) mass-transport complexes. The first initially reworked the
southern part of the sub-basin fill together with the early onlap wedge, the second remobilised the onlap wedge, and the third
records failure of the upper part of the slope well above the wedge. The first two were toe-confined failures, the third and
furthest travelled was confined by basin axis topography. All three failures are lateral to or directly overlain by ‘megabed’ sheets
on the basin floor, implying either a common trigger (earthquakes) or slope instability following reflection of large volume flows.
Tabernas turbidites highlight the role of basin tectonics (as opposed to up-dip supply and sea level fluctuations) in directly impacting
on deep-water processes and stratigraphy. Small deep-water transtensional sub-basins opened up along long transfer faults
accommodating regional extension.
Frontiers in Earth Science, doi.org/10.3389/feart.2021.767286, 2021.