Plio-Pleistocene synsedimentary fault compartments, foundation for the eastern Olduvai Basin paleoenvironmental mosaic, Tanzania

Landscape distribution of Oldowan stone artifact assemblages across the fault compartments of the eastern Olduvai Lake Basin during early lowermost Bed II times

“…1.785 Ma (Blumenschine et al, 2003). Stollhofen and Stanistreet (2012) demonstrate synsedimentary fault activity before and during Tuff IF times and during the following first four parasequences of pre-incisional lowermost Bed II. Synsedimentary fault activity is indicated by differences in the lithofacies, parasequence thicknesses, and thickness differences of Tuff IF and its subunits across faults (Figs.…”

“…For the first parasequence of lowermost Bed II, total offsets at synsedimentary faults were 0.5 to 1.4 m, with average calculated slip rates of 13 to 35 cm/ky (Stollhofen and Stanistreet, 2012). Depending on the duration of fault recurrence intervals, relief at the faults might have been several decimeters to 1 m, although the topography would have been leveled-off successively by the combined effects of gravitational footwall collapse, erosion of streams into the elevated footwalls, and contemporaneous accumulation of footwall-derived debris and lake sediments on the adjacent, downthrown hangingwall block.…”

“…2;Stollhofen and Stanistreet, 2012). We focus on the early portion of lowermost Bed II prior to valley incision.…”

“…Depending on the duration of fault recurrence intervals, relief at the faults might have been several decimeters to 1 m, although the topography would have been leveled-off successively by the combined effects of gravitational footwall collapse, erosion of streams into the elevated footwalls, and contemporaneous accumulation of footwall-derived debris and lake sediments on the adjacent, downthrown hangingwall block. Topographic effects on depositional systems would be most pronounced during lake level lowstands when fluvial systems, sensitive to fault displacements as little as 0.1 mm/a, occupied the area (Stollhofen and Stanistreet, 2012). Renewed fault activity during a lake regression would have once again imparted relief at still active faults.…”

“…Stratigraphic measured sections of Tuff IF on the hangingwall and footwall of the KK Fault, showing differences in thickness and lithology related to synsedimentary fault activity (afterStollhofen and Stanistreet, 2012).…”