A crustal thickness map of Africa derived from a global gravity field model using Euler deconvolution

Getachew E. Tedla, M. van der Meijde, Andrew Arnold Nyblade, F. D. Van der Meer

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

We develop a new continental scale crustal model for Africa by modelling the free-air gravity anomaly EIGEN-GL04C, which was developed from 30 months of GRACE Level 1B data covering the period from 2003 February to 2005 July, and surface gravity data from seven different sources. From this gravity model, crustal thickness is estimated using 3-D Euler deconvolution, a method that does not rely on a priori depth and density constraints. The results are in good agreement (i.e. within 5km) of seismically determined Moho depth estimates from across the continent, except for narrow tectonic regions, such as rift valleys, and areas where seismic velocity models of the crust indicate a gradational Moho. The results show that crustal thickness is fairly homogeneous, with an average crustal thickness for the whole continent of 39±2(SD) km. The average Moho depth for most terrains is within 5km of the continental average, and there is little variability between terrains of different age. The average thickness for Archean, Proterozoic and Palaeozoic crust is 39, 39 and 41km, respectively. Crustal thickness in sedimentary basins across northern and central Africa varies between 33 and 36km. Through comparison with global averages for similar-aged terrains, we find that African crustal thickness does not deviate significantly from the thickness of crust in other parts of the world.

Original languageEnglish (US)
Pages (from-to)1-9
Number of pages9
JournalGeophysical Journal International
Volume187
Issue number1
DOIs
StatePublished - Oct 1 2011

Fingerprint

crustal thickness
Deconvolution
deconvolution
gravity field
Gravitation
gravitation
Moho
crust
crusts
Tectonics
continents
gravity
GRACE
seismic velocity
rift zone
gravity anomaly
sedimentary basin
Archean
Air
Proterozoic

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology

Cite this

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abstract = "We develop a new continental scale crustal model for Africa by modelling the free-air gravity anomaly EIGEN-GL04C, which was developed from 30 months of GRACE Level 1B data covering the period from 2003 February to 2005 July, and surface gravity data from seven different sources. From this gravity model, crustal thickness is estimated using 3-D Euler deconvolution, a method that does not rely on a priori depth and density constraints. The results are in good agreement (i.e. within 5km) of seismically determined Moho depth estimates from across the continent, except for narrow tectonic regions, such as rift valleys, and areas where seismic velocity models of the crust indicate a gradational Moho. The results show that crustal thickness is fairly homogeneous, with an average crustal thickness for the whole continent of 39±2(SD) km. The average Moho depth for most terrains is within 5km of the continental average, and there is little variability between terrains of different age. The average thickness for Archean, Proterozoic and Palaeozoic crust is 39, 39 and 41km, respectively. Crustal thickness in sedimentary basins across northern and central Africa varies between 33 and 36km. Through comparison with global averages for similar-aged terrains, we find that African crustal thickness does not deviate significantly from the thickness of crust in other parts of the world.",
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A crustal thickness map of Africa derived from a global gravity field model using Euler deconvolution. / Tedla, Getachew E.; van der Meijde, M.; Nyblade, Andrew Arnold; Van der Meer, F. D.

In: Geophysical Journal International, Vol. 187, No. 1, 01.10.2011, p. 1-9.

Research output: Contribution to journalArticle

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