Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-28T01:31:57.322Z Has data issue: false hasContentIssue false
  • English
  • Français

Late Permian mafic rocks identified within the Doba basin of southern Chad and their relationship to the boundary of the Saharan Metacraton

Published online by Cambridge University Press:  06 May 2015

J. GREGORY SHELLNUTT ,
TUNG-YI LEE ,
CHIH-CHENG YANG ,
SHIN-TAI HU ,
JONG-CHANG WU ,
KUO-LUNG WANG  and
CHING-HUA LO
J. GREGORY SHELLNUTT*
Affiliation:
National Taiwan Normal University, Department of Earth Science, 88 Tingzhou Road Section 4, Taipei 116, Taiwan
TUNG-YI LEE
Affiliation:
National Taiwan Normal University, Department of Earth Science, 88 Tingzhou Road Section 4, Taipei 116, Taiwan
CHIH-CHENG YANG
Affiliation:
Chinese Petroleum Corporation-Taiwan, Exploration and Development Research Institute, Wen Fa Road, Miaoli 36042, Taiwan
SHIN-TAI HU
Affiliation:
Chinese Petroleum Corporation-Taiwan, Exploration and Development Research Institute, Wen Fa Road, Miaoli 36042, Taiwan
JONG-CHANG WU
Affiliation:
Chinese Petroleum Corporation-Taiwan, Exploration and Development Research Institute, Wen Fa Road, Miaoli 36042, Taiwan
KUO-LUNG WANG
Affiliation:
Academia Sinica Institute of Earth Sciences, 128 Academia Road Section 2, Taipei 115, Taiwan
CHING-HUA LO
Affiliation:
National Taiwan University, Department of Geosciences, P.O. Box 13–318, Taipei 106, Taiwan
*
†Author for correspondence: jgshelln@ntnu.edu.tw
Get access Rights & Permissions [Opens in a new window]

Abstract

The Doba gabbro was collected from an exploration well through the Cretaceous Doba basin of southern Chad. The gabbro is composed mostly of plagioclase, clinopyroxene and Fe–Ti oxide minerals and displays cumulus mineral textures. Whole-rock 40Ar–39Ar step-heating geochronology yielded a Late Permian plateau age of 257 ± 1 Ma. The major and trace elemental geochemistry shows that the gabbro is tholeiitic in composition and has trace element ratios (i.e. La/YbN > 7; Sm/YbPM > 3.4; Nb/Y > 1; Zr/Y > 5) indicative of a basaltic melt derived from a garnet-bearing mantle source. The moderately enriched Sr–Nd isotopes (i.e. ISr = 0.70495 to 0.70839; ɛNd(T) = −1.0 to −1.3) fall within the mantle array (i.e. OIB-like) and are similar to other Late Permian plutonic rocks of North-Central Africa (i.e. ISr = 0.7040 to 0.7070). The enriched isotopic composition of the Doba gabbro contrasts with the more depleted compositions of the spatially associated Neoproterozoic post-Pan-African within-plate granites. The contrasting Nd isotope composition between the older within-plate granites and the younger Doba gabbro indicates that different mantle sources produced the rocks and thus may mark the southern boundary of the Saharan Metacraton.

Keywords

Late PermianSaharan Metacraton40Ar–39Ar datingDoba basinChad
Type
Original Articles
Information
Geological Magazine , Volume 152 , Issue 6 , November 2015 , pp. 1073 - 1084
Copyright
Copyright © Cambridge University Press 2015 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abdelsalam, M., Gao, S. S. & Liegeois, J.-P. 2011. Upper mantle structure of the Saharan Metacraton. Journal of African Earth Sciences 60, 328–36.CrossRefGoogle Scholar
Abdelsalam, M., Liegeois, J.-P. & Stern, R. J. 2002. The Saharan Metacraton. Journal of African Earth Sciences 34, 119–36.CrossRefGoogle Scholar
Almond, D. C. 1991. Anorogenic magmatism in northeast Africa. In Geology of Libya (ed. Salem, M. J.), pp. 2495–510. Amsterdam: Elsevier.Google Scholar
Bailey, D. K. & Woolley, A. R. 2005. Repeated, synchronous magmatism within Africa: timing, magnetic reversals, and global tectonics. In Plates, Plumes, and Paradigms (eds Foulger, G. R., Natland, J. H., Presnall, D. C. & Anderson, D. L.), pp. 365–77. Geological Society of America, Special Paper no. 388.Google Scholar
Baksi, A. K. 2001. Search for a deep-mantle component in mafic lavas using a Nb-Y-Zr plot. Canadian Journal of Earth Sciences 38, 813–24.Google Scholar
Black, R. & Liegeois, J.-P. 1993. Cratons, mobile belts, alkaline rocks and continental lithospheric mantle: the Pan-African testimony. Journal of the Geological Society, London 150, 89–98.CrossRefGoogle Scholar
Burke, K. 2001. Origin of the Cameroon Line of volcano-capped swells. Journal of Geology 109, 349–62.CrossRefGoogle Scholar
Cabanis, B. & Lecolle, M. 1989. Le diagramme La/10-Y/15-Nb/8: un outil pour la discrimination des series volcanique et la mise en evidence des processus de mélange et/ou de contamination crustale. Comptes Redus l’Academie des Sciences 309, 2023–9.Google Scholar
Caby, R. 2003. Terrane assembly and geodynamic evolution of central-western Hogger: a synthesis. Journal of African Earth Sciences 37, 133–59.CrossRefGoogle Scholar
Caby, R. & Monie, P. 2003. Neoproterozoic subductions and differential exhumation of western Hogger (southwest Algeria): new structural, petrological and geochronological evidence. Journal of African Earth Sciences 37, 269–93.CrossRefGoogle Scholar
Campbell, I. H. 2002. Implications of Nb/U, Th/U and Sm/Nd in plume magmas for the relationship between continental and oceanic crust formation and the development of the depleted mantle. Geochimica et Cosmochimica Acta 66, 1651–61.CrossRefGoogle Scholar
Condie, K. C. 2003. Incompatible element ratios in oceanic basalts and komatiites: tracking deep mantle sources and continental growth rates with time. Geochemistry, Geophysics, Geosystems 4, doi: 10.1029/2002/GC000333.CrossRefGoogle Scholar
Condie, K. C. 1997. Source of Proterozoic mafic dyke swarms: constraints from Th/Ta and La/Yb ratios. Precambrian Research 81, 3–14.CrossRefGoogle Scholar
Dostal, J., Caby, R., Keppie, J. D. & Maza, M. 2002. Neoproterozoic magmatism in southwestern Algeria (Sebkha el Melah inlier): a northern extension of the Trans-Saharan orogeny. Journal of African Earth Sciences 35, 213–25.CrossRefGoogle Scholar
Elkins-Tanton, L. T. 2005. Continental magmatism caused by lithospheric delamination. In Plates, Plumes, and Paradigms (eds Foulger, G. R., Natland, J. H., Presnall, D. C., & Anderson, D. L.), pp. 449–61. Geological Society of America, Special Paper no. 388.Google Scholar
Fabre, J. 1988. Les series paleozoiques d’Afrique: une approche. Journal of African Earth Sciences 7, 1–40.CrossRefGoogle Scholar
Fitton, J. G., Saunders, A. D., Norry, M. J., Hardarson, B. S. & Taylor, R. N. 1997. Thermal and chemical structure of the Iceland plume. Earth and Planetary Science Letters 153, 197–208.CrossRefGoogle Scholar
Fleck, R. J., Sutter, J. F. & Elliot, D. H. 1977. Interpretation of discordant 40Ar/39Ar age-spectra of Mesozoic tholeiites from Antarctica. Geochimica et Cosmochimica Acta 41, 15–32.CrossRefGoogle Scholar
Genik, G. J. 1993. Petroleum geology of Cretaceous-Tertiary rift basins in Niger, Chad, and Central African Republic. American Association of Petroleum Geology B 77, 1405–34.Google Scholar
Guiraud, R., Bosworth, W., Thierry, J. & Delplanque, A. 2005. Phanerozoic geological evolution of northern and central Africa: an overview. Journal of African Earth Sciences 43, 83–143.CrossRefGoogle Scholar
Guiraud, R., Doumnang Mbaigane, J.-C., Carretier, S. & Dominguez, S. 2000. Evidence for a 6000 km length NW-SE-striking lineament in northern Africa: the Tibesti lineament. Journal of the Geological Society, London 157, 897–900.CrossRefGoogle Scholar
Guiraud, R., Issawi, B. & Bellion, Y. 1985. Les lineaments guineo-nubiens: un trait structural majeur l’echelle de la plaque africaine. Comptes Rendus Hebdomadaires des Seances de l’Academie des Sciences 300, 17–20.Google Scholar
Hawkesworth, C. & Schersten, A. 2007. Mantle plumes and geochemistry. Chemical Geology 241, 319–31.CrossRefGoogle Scholar
Hohndorf, A., Meinhold, K.-D. & Vail, J. R. 1994. Geochronology of anorogenic igneous complexes in the Sudan: isotopic investigations in North Kordofan, the Nubian Desert and the Red Sea Hills. Journal of African Earth Sciences 19, 3–15.CrossRefGoogle Scholar
Isseini, M., Andre-Mayer, A.-S., Vanderhaeghe, O., Barbey, P. & Deloule, E. 2012. A-type granites form the Pan-African orogenic belt in south-western Chad constrained using geochemistry, Sr-Nd isotopes and U-Pb geochronology. Lithos 153, 39–52.CrossRefGoogle Scholar
Kroner, A. 1980. Pan African crustal evolution. Episodes 3, 3–8.CrossRefGoogle Scholar
King, S. D. 2005. North Atlantic topographic and geoid anomalies: the results of a narrow ocean basin and cratonic roots? In Plates, Plumes, and Paradigms (eds Foulger, G. R., Natland, J. H., Presnall, D. C., & Anderson, D. L.), pp. 653–64. Geological Society of America, Special Paper no. 388.Google Scholar
King, S. D. & Anderson, D. L. 1998. Edge-driven convection. Earth and Planetary Science Letters 160, 289–96.CrossRefGoogle Scholar
King, S. D. & Anderson, D. L. 1995. An alternative mechanism of flood basalt formation. Earth and Planetary Science Letters 136, 269–79.CrossRefGoogle Scholar
Lay, C. & Reichelt, R. 1971. Sur l’age et la significance des intrusions de dolerites tholeitique dans le basin de Taoudenni (Afrique Occidentale). Comptes Rendus de l’Academe des Sciences 272, 374–6.Google Scholar
Liegeois, J.-P., Abdelsalam, M. G., Ennih, N. & Ousbadi, A. 2013. Metacraton: nature, genesis and behavior. Gondwana Research 23, 220–37.CrossRefGoogle Scholar
Liegeois, J.-P., Bertrand, H., Black, R., Caby, R. & Fabre, J. 1983, Permian alkaline undersaturated and carbonatite province, and rifting along the West African craton. Nature 305, 42–3.CrossRefGoogle Scholar
Liegeois, J.-P., Sauvage, J. F. & Black, R. 1991. The Permo-Jurassic alkaline province of Tadhak, Mali: geology, geochronology and tectonic significance. Lithos 27, 95–105.CrossRefGoogle Scholar
Massa, D. & Delort, T. 1984. Evolution du basin de Syrte (Libye) du Cambrien au Cretace basal. Bulletin de la Societe geologique de France XXVI, 1087–96.CrossRefGoogle Scholar
Odin, G. S. et al. (35 collaborators). 1982. Interlaboratory standards for dating purposes. In Numerical Dating in Stratigraphy (ed. Odin, G. S.), pp. 123–49. Chichester: Wiley and Sons.Google Scholar
Peate, D. 1997. The Parana-Etendeka province. In Large Igneous Provinces: Continental, Oceanic, and Planetary Flood Volcanism (eds Mahoney, J. J. & Coffin, M. E.), pp. 217–45. American Geophysical Union, Geophysical Monograph Series vol. 100. Washington, DC, USA.Google Scholar
Penaye, J., Kroner, A., Toteu, S. F., Van Schmus, W. R. & Doumnang, J.-C. 2006. Evolution of the Mayo Kebbi region as reveal by zircon dating: an early (ca. 740 Ma) Pan-African magmatic arc in south-western Chad. Journal of African Earth Sciences 44, 530–42.CrossRefGoogle Scholar
Rahaman, M. A., van Breemen, O., Bowden, P. & Bennett, J. N. 1984. Age migrations of anorogenic ring complexes in northern Nigeria. Journal of Geology 92, 173–84.CrossRefGoogle Scholar
Renne, P. R., Mundil, R., Balco, G., Min, K. & Ludwig, K. R. 2010. Joint determination of 40K decay constants and 40Ar*/40K for the Fish Canyon sanidine standard, and improved accuracy for 40Ar/39Ar geochronology. Geochimica et Cosmochimica Acta 74, 5349–67.CrossRefGoogle Scholar
Rogers, J.J., Unrug, R. & Sultan, M. 1995. Tectonic assembly of Gondwana. Journal of Geodynamics 19, 1–34.CrossRefGoogle Scholar
Schluter, T. 2008. Geological Atlas of Africa. Berlin: Springer-Verlag, 307 pp.Google Scholar
Shellnutt, J. G., Wang, K.-L., Zellmer, G. F., Iizuka, Y., Jahn, B.-M., Pang, K.-W., Qi, L. & Zhou, M.-F. 2011. Three Fe-Ti oxide ore-bearing gabbro-granitoid complexes in the Panxi region of the Permian Emeishan large igneous province, SW China. American Journal of Science 311, 773–812.CrossRefGoogle Scholar
Sun, S.-S. & McDonough, W. F. 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In Magmatism in the Ocean Basins (eds Saunders, A. D. & Norry, M. J.), pp 313–435. Geological Society of London, Special Publication no. 42.Google Scholar
Toteu, S. F., Penaye, J. & Djomani, Y. P. 2004. Geodynamic evolution of the Pan-African belt in central Africa with special reference to Cameroon. Canadian Journal of Earth Sciences 41, 73–85.CrossRefGoogle Scholar
Toteu, S. F., Penaye, J., Deloule, E., Van Schmis, W. R. & Tchamen, R. 2006. Diachronous evolution of volcano-sedimentary basins north of the Congo craton: insights from U-Pb ion microprobe dating of zircons from the Poli, Lom and Yaounde groups (Cameroon). Journal of African Earth Sciences 44, 428–42.CrossRefGoogle Scholar
Vail, J. R. 1989. Ring complexes and related rocks in Africa. Journal of African Earth Sciences 8, 19–40.CrossRefGoogle Scholar
Veevers, J. J. 2003. Pan-African is pan-Gondwanaland: oblique convergence drives rotation during 650–500 Ma assembly: Geology 31, 501–4.2.0.CO;2>CrossRefGoogle Scholar
Weis, D., Liegeois, J.-P. & Black, R. 1987. Tadhak alkaline ring-complex (Mali): existence of U-Pb isochrones and “Dupal” signature 270 Ma ago. Earth and Planetary Science Letters 82, 316–22.CrossRefGoogle Scholar
Wilson, M. & Guiraud, R. 1992. Magmatism and rifting in western and central Africa, from Late Jurassic to recent times. Tectonophysics 213, 203–25.CrossRefGoogle Scholar
Wilson, M., Guiraud, R., Moreau, C. & Bellion, Y. J.-C. 1998. Late Permian to recent magmatic activity on the African-Arabian margin of Tethys. In Petroleum Geology of North Africa (eds MacGregor, D. S., Moody, R. T. J. & Clark-Lowes, D. D.), pp. 231–63. Geological Society of London, Special Publication no. 132.Google Scholar
Supplementary material: File

Shellnutt supplementary material S1

Table

Download Shellnutt supplementary material S1(File)
File 32.3 KB