Seismic imaging of the Olduvai Basin, Tanzania

Beitrag in einer Fachzeitschrift


Details zur Publikation

Autorinnen und Autoren: Lu K, Hanafy S, Stanistreet I, Njau J, Schick K, Toth N, Stollhofen H, Schuster G
Zeitschrift: Palaeogeography, Palaeoclimatology, Palaeoecology
Jahr der Veröffentlichung: 2019
Band: 533
ISSN: 0031-0182


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.


FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

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


Einrichtungen weiterer Autorinnen und Autoren

King Abdullah University of Science and Technology (KAUST) / جامعة الملك عبد الله للعلوم و التقنية
King Fahd University of Petroleum and Minerals (KFUPM)
Stone Age Institute
The University of Liverpool


Zitierweisen

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).

BibTeX: 

Zuletzt aktualisiert 2019-11-07 um 07:23