About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Special Volumes

Abstract

Click to view this article in PDF format.

Chapter from:
AAPG Studies in Geology #44: Geoscience of Rift Systems-Evolution of East Africa
Edited by C.K. Morley
Copyright ©1999 by The American Association of Petroleum Geologists. All rights reserved.
AAPG Studies in Geology #44, Chapter 3: Geology and Previous HitGeophysicsNext Hit of the Lotikipi Plain, by W.A. Wescott, S.T. Wigger, D.M. Stone, and C.K. Morley, Pages 55 - 66

 

 

Chapter 3

Geology and Previous HitGeophysicsTop of the Lotikipi Plain

 

W.A. Wescott
S.T. Wigger
D.M. Stone

Amoco Production Company
Houston, Texas, U.S.A.

 

C.K. Morley
Department of Petroleum Geoscience
University of Brunei Darussalam
Negara Brunei Darrussalam

 

Abstract

Reconnaissance seismic reflection data show that the Lotikipi Plain is underlain by two faulted synformal basins, called the Gatome and Lotikipi Basins. Gravity data indicate the basins are oriented north-south. Ties between the seismic data and outcrops indicate that the basins are filled by basalt and rhyolite flows (Oligocene-early Miocene) capped by sedimentary deposits. The quality of the seismic data degrades significantly within the volcanic section, hence the deeper basin geometry and depth to the Precambrian basement are poorly defined. However, in the Gatome Basin a half graben basin within or beneath the volcanics is imaged, suggesting the existence of a Paleogene (more likely) or Cretaceous (less likely) sedimentary basin within or below the volcanics. Previous interpretations have suggested that volcanism preceded rifting in the Lotikipi Plain area. Such evidence has been used in support of active rifting in the Kenya Rift. However, here it is suggested that extension preceded rifting. Whether the rifting is related to the Sudan-Anza Graben (Cretaceous-Paleogene) rift system, or the eastern branch of the East African Rift System (EARS) is uncertain. Extension is unlikely to have been large enough to cause enough partial melting of the mantle purely by passive extension, because the volumes of lava in the region are large (450,000 km3) and the beta factor unlikely to exceed 1.5. Consequently, an active mantle plume under the region must be assumed if the magma has ascended vertically. The lavas are thought to have been extruded at the end of rifting and into the early stages of thermal subsidence. Tectonic inversion affected the area during the late Miocene-Pliocene.

 

View the First Page

A text abstract of this article is not available. The first page of the PDF appears below.

You may download the first page as a PDF.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24