Bouguer and mantle gravity maps of Nigeria. Issue 27 (13th December 2022)
- Record Type:
- Journal Article
- Title:
- Bouguer and mantle gravity maps of Nigeria. Issue 27 (13th December 2022)
- Main Title:
- Bouguer and mantle gravity maps of Nigeria
- Authors:
- Apeh, Ojima Isaac
Tenzer, Robert
Kemgang Ghomsi, Franck Eitel
Rathnayake, Samurdhika - Abstract:
- Abstract: We used global gravitational models together with topographic, bathymetric, and lithospheric density structure datasets to compile Bouguer and mantle gravity maps of Nigeria, and then used these gravity maps to interpret the crustal and upper mantle structure in this country. We applied methods for a spherical harmonic analysis and synthesis of gravitational and lithospheric density structure models to produce both gravity maps. Whereas existing Bouguer gravity datasets for different parts of Nigeria were computed by applying only a simple planar Bouguer gravity reduction and a planar terrain gravity correction, our approach took into consideration the Earth's spherical approximation and the spherical terrain correction, the ocean density contrast as well as density variations within sediments and the underlying consolidated crust. This study also provides the first mantle gravity map of Nigeria. Our results show that the free-air gravity pattern reflects mainly a topographic relief with prevailing positive values over topographically elevated regions, while Cretaceous sedimentary basins are characterized by low negative values. The pattern in the Bouguer gravity map exhibits mainly a Moho signature, with low negative values associated with a regional Moho deepening beneath the Sokoto Basin and the North Shield Belt. The pattern in the mantle gravity map exhibits a thermal signature of the lithospheric mantle. The high values (≥ 1000 mGal) of the mantle gravityAbstract: We used global gravitational models together with topographic, bathymetric, and lithospheric density structure datasets to compile Bouguer and mantle gravity maps of Nigeria, and then used these gravity maps to interpret the crustal and upper mantle structure in this country. We applied methods for a spherical harmonic analysis and synthesis of gravitational and lithospheric density structure models to produce both gravity maps. Whereas existing Bouguer gravity datasets for different parts of Nigeria were computed by applying only a simple planar Bouguer gravity reduction and a planar terrain gravity correction, our approach took into consideration the Earth's spherical approximation and the spherical terrain correction, the ocean density contrast as well as density variations within sediments and the underlying consolidated crust. This study also provides the first mantle gravity map of Nigeria. Our results show that the free-air gravity pattern reflects mainly a topographic relief with prevailing positive values over topographically elevated regions, while Cretaceous sedimentary basins are characterized by low negative values. The pattern in the Bouguer gravity map exhibits mainly a Moho signature, with low negative values associated with a regional Moho deepening beneath the Sokoto Basin and the North Shield Belt. The pattern in the mantle gravity map exhibits a thermal signature of the lithospheric mantle. The high values (≥ 1000 mGal) of the mantle gravity disturbances detected over the Benin-Nigerian Block and the Phanerozoic cover of the West African Mobile Zone are possibly associated with a thermal signature of the lithospheric mantle. Another thermal signature of the lithospheric mantle along the Cameroon Volcanic Line partially outlines margins between the Oubanguides Neoproterozoic Belt and the southern extension of the West African Mobile Zone. … (more)
- Is Part Of:
- Geocarto international. Volume 37:Issue 27(2023)
- Journal:
- Geocarto international
- Issue:
- Volume 37:Issue 27(2023)
- Issue Display:
- Volume 37, Issue 27 (2023)
- Year:
- 2023
- Volume:
- 37
- Issue:
- 27
- Issue Sort Value:
- 2023-0037-0027-0000
- Page Start:
- 16342
- Page End:
- 16369
- Publication Date:
- 2022-12-13
- Subjects:
- Bouguer gravity maps -- lithosphere -- geophysical data -- gravimetric interpretation -- mantle
Remote sensing -- Periodicals
Geographic information systems -- Periodicals
Geology -- Periodicals
Cartography -- Periodicals
621.3678 - Journal URLs:
- http://www.tandf.co.uk/journals/titles/10106049.asp ↗
http://www.tandfonline.com/toc/tgei20/current ↗
http://www.tandfonline.com/ ↗ - DOI:
- 10.1080/10106049.2022.2108908 ↗
- Languages:
- English
- ISSNs:
- 1010-6049
- Deposit Type:
- Legaldeposit
- View Content:
- Available online (eLD content is only available in our Reading Rooms) ↗
- Physical Locations:
- British Library DSC - 4116.917700
British Library DSC - BLDSS-3PM
British Library HMNTS - ELD Digital store - Ingest File:
- 26055.xml