Seismic imaging of the Olduvai Basin, Tanzania

Lu K, Hanafy S, Stanistreet I, Njau J, Schick K, Toth N, Stollhofen H, Schuster G (2019)

Publication Type: Journal article

Publication year: 2019

Journal

Palaeogeography, Palaeoclimatology, Palaeoecology Elsevier

Book Volume: 533

Article Number: 109246

DOI: 10.1016/j.palaeo.2019.109246

Abstract

A 5.6-km-long line of refraction and reflection seismic data spanning the Pliocene-Pleistocene fill of the Olduvai Basin, Tanzania is presented. The line is oriented along a northwest-southeast profile through the position of Olduvai Gorge Coring Project (OGCP) Borehole 2A. Our aims are to (1) delineate the geometry of the basin floor by tracing bedrock topography of the metaquartzitic and gneissic basement, (2) map synsedimentary normal faults and trace individual strata at depth, and (3) provide context for the sequence observed in OGCP cores. Results with refraction tomography and poststack migration show that the maximum basin depth is around 405 m (±25 m) in the deepest portion, which quadruples the thickness of the basin-fill previously known from outcrops. Variations in seismic velocities show the positions of lower density lake claystones and higher density well-cemented sedimentary sequences. The Bed I Basalt lava is a prominent marker in the refraction seismic results. Bottom-most sediments are dated to >2.2 Ma near where Borehole 2A bottoms out at the depth of 245 m. However, the seismic line shows that the basin-fill reaches a maximum stratigraphic thickness of around 380 m deep at Borehole 2A, in the western basin where the subsidence was greatest. This further suggests that potential hominin palaeoenvironments were available and preserved within the basin-fill possibly as far back as around 4 Ma, applying a temporal extrapolation using the average sediment accretion rate.

Authors with CRIS profile

Harald Stollhofen Lehrstuhl für Geologie (Exogene Dynamik)

Related research project(s)

Reconstructing high-resolution paleoenvironmental contexts of hominin evolution through core records at Olduvai Gorge, Tanzania Sept. 1, 2016 - Nov. 30, 2019

Involved external institutions

King Abdullah University of Science and Technology (KAUST) / جامعة الملك عبد الله للعلوم و التقنية SA Saudi Arabia (SA) King Fahd University of Petroleum and Minerals (KFUPM) SA Saudi Arabia (SA) Stone Age Institute US United States (USA) (US) The University of Liverpool GB United Kingdom (GB)

How to cite

APA:

Lu, K., Hanafy, S., Stanistreet, I., Njau, J., Schick, K., Toth, N.,... Schuster, G. (2019). Seismic imaging of the Olduvai Basin, Tanzania. Palaeogeography, Palaeoclimatology, Palaeoecology, 533. https://dx.doi.org/10.1016/j.palaeo.2019.109246

MLA:

Lu, Kai, et al. "Seismic imaging of the Olduvai Basin, Tanzania." Palaeogeography, Palaeoclimatology, Palaeoecology 533 (2019).

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