Interplay
Between Tectonics and Sedimentation in a Deep-Water ‘Mini-Basin’ Setting, Tabernas, SE Spain
Baudouy, Lucie1,
Peter D.W. Haughton1, John J. Walsh1, Marco Patacci2
(1) University College Dublin, Dublin 4, Ireland (2) University College Dublin, N/A, Ireland
Basin geometry can have a significant
impact on deep-water sedimentation, particularly in tectonically-active basins
or those with a mobile salt or shale substrate. The well exposed Neogene Tabernas Basin (SE Spain) was characterised by a number of oblique-slip intrabasinal faults that propagated to the palaeo-sea bed. The faults provided local ponded accommodation for gravity currents, and influenced
flow routing and slope stability. The early basin fill was characterised
by extensive east-facing, axial slopes into which slope channels were incised
and bypassed sediment. As faults propagated to the sea bed, they bound local
areas of rapid subsidence that became deeps analogous to mini-basins in which
turbidity currents were preferentially trapped and fully ponded,
together with mass transport complexes. The ponded turbidite sheets are either structurally truncated against
faults at the mini-basin margins, onlap surrounding
slopes or are involved in local unconformities reflecting progressive near
fault deformation. Variations in turbidite thickness
reflect bathymetry on the floor of the depressions. As activity on the intrabasinal faults waned, the local depocentres
filled and turbidites onlapped
beyond the area of initial fault containment onto surrounding slopes; the
structure of the partially contained turbidites
deposited in the expanded basin differ from those in the earlier fully
contained faulted depressions. Continuing tectonic activity following healing
of the mini-basin depressions resulted in particularly unstable slopes with
episodic whole scale slumping, sliding and failure of the onlap
wedges.