Plio-Pleistocene syn-sedimentary fault compartments underpin lake margin paleoenvironmental mosaic, Olduvai Gorge, Tanzania

Journal article
(Original article)


Publication Details

Author(s): Stollhofen H, Stanistreet IG
Journal: Journal of Human Evolution
Publication year: 2012
Volume: 63
Journal issue: 2
Pages range: 309-327
ISSN: 0047-2484
Language: English


Abstract


Normal faults displacing Upper Bed I and Lower Bed II strata of the Plio-Pleistocene Lake Olduvai were

studied on the basis of facies and thickness changes as well as diversion of transport directions across

them in order to establish criteria for their synsedimentary activity. Decompacted differential thicknesses

across faults were then used to calculate average fault slip rates of 0.05e0.47 mm/yr for the Tuff

IE/IF interval (Upper Bed I) and 0.01e0.13 mm/yr for the Tuff IF/IIA section (Lower Bed II). Considering

fault recurrence intervals of w1000 years, fault scarp heights potentially achieved average values of 0.05

e0.47 m and a maximum value of 5.4 m during Upper Bed I, which dropped to average values of 0.01

e0.13 m and a localized maximum of 0.72 m during Lower Bed II deposition.

Synsedimentary faults were of importance to the form and paleoecology of landscapes utilized by early

hominins, most traceably and provably Homo habilis as illustrated by the recurrent density and

compositional pattern of Oldowan stone artifact assemblage variation across them. Two potential relationship

factors are: (1) fault scarp topographies controlled sediment distribution, surface, and subsurface

hydrology, and thus vegetation, so that a resulting mosaic of microenvironments and paleoecologies

provided a variety of opportunities for omnivorous hominins; and (2) they ensured that the most voluminous

and violent pyroclastic flows from the Mt. Olmoti volcano were dammed and conduited away

from the Olduvai Basin depocenter, when otherwise a single or set of ignimbrite flows might have filled

and devastated the topography that contained the central lake body. In addition, hydraulically active

faults may have conduited groundwater, supporting freshwater springs and wetlands and favoring

growth of trees.



FAU Authors / FAU Editors

Stollhofen, Harald Prof. Dr.
Lehrstuhl für Geologie (Exogene Dynamik)


External institutions
The University of Liverpool


How to cite

APA:
Stollhofen, H., & Stanistreet, I.G. (2012). Plio-Pleistocene syn-sedimentary fault compartments underpin lake margin paleoenvironmental mosaic, Olduvai Gorge, Tanzania. Journal of Human Evolution, 63(2), 309-327. https://dx.doi.org/10.1016/j.jhevol.2011.10.002

MLA:
Stollhofen, Harald, and Ian G. Stanistreet. "Plio-Pleistocene syn-sedimentary fault compartments underpin lake margin paleoenvironmental mosaic, Olduvai Gorge, Tanzania." Journal of Human Evolution 63.2 (2012): 309-327.

BibTeX: 

Last updated on 2018-09-08 at 16:08