DC resistivity and seismic refraction survey across the SE margin of Lake Ngami, NW Botswana

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Seismic refraction survey and DC resistivity measurements were made across the margin of the Lake Ngami. The structure and stratigraphy at the lake were determined. High resolution aeromagnetic data showed a prominent anomaly coinciding with the Kunyere Fault. Estimated depths to magnetic sources are increasing towards the lake. Two velocity layers were mapped. The top layer (500 m/s) is thin outside the lake and thicker inside the lake. The underlying layer (3125 m/s) has undeterminable thickness. Resistivity sounding results inside the lake showed that the low velocity layer has four sub-units: dry hard clays; diatomaceous earth; soft clays interlayered with silts; and wet whitish clays interlayered with silts. Normal faults were mapped along the profile with a total displacement up to 50 m. The results of the study indicate that the formation of the Lake Ngami basin was structurally controlled and probably initiated by the tectonics of the Okavango Rift Zone.

Original languageEnglish
Pages (from-to)728-742
Number of pages15
JournalActa Geophysica
Volume57
Issue number3
DOIs
Publication statusPublished - Jun 11 2009

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Botswana
seismic refraction
lakes
refraction
electrical resistivity
margins
direct current
lake
clays
sediments
clay
diatomite
aeromagnetic survey
soft clay
rift zone
stratigraphy
normal fault
sounding
low speed
tectonics

All Science Journal Classification (ASJC) codes

  • Geophysics

Cite this

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abstract = "Seismic refraction survey and DC resistivity measurements were made across the margin of the Lake Ngami. The structure and stratigraphy at the lake were determined. High resolution aeromagnetic data showed a prominent anomaly coinciding with the Kunyere Fault. Estimated depths to magnetic sources are increasing towards the lake. Two velocity layers were mapped. The top layer (500 m/s) is thin outside the lake and thicker inside the lake. The underlying layer (3125 m/s) has undeterminable thickness. Resistivity sounding results inside the lake showed that the low velocity layer has four sub-units: dry hard clays; diatomaceous earth; soft clays interlayered with silts; and wet whitish clays interlayered with silts. Normal faults were mapped along the profile with a total displacement up to 50 m. The results of the study indicate that the formation of the Lake Ngami basin was structurally controlled and probably initiated by the tectonics of the Okavango Rift Zone.",
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DC resistivity and seismic refraction survey across the SE margin of Lake Ngami, NW Botswana. / Shemang, Elisha M.; Molwalefhe, Loago N.

In: Acta Geophysica, Vol. 57, No. 3, 11.06.2009, p. 728-742.

Research output: Contribution to journalArticle

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