Arabian Journal of Geosciences

, 11:539 | Cite as

Rare earth and trace element geochemistry of Cretaceous kerogens

  • Akinsehinwa AkinluaEmail author
  • Solomon Adeniyi Adekola
  • Adeyemi Adio Kumolu
Original Paper


The relationship between rare earth elements (REEs) and the age of Cretaceous kerogens or petroleum source rocks is not known. In this study, kerogen samples isolated from petroleum source rocks from the Cretaceous Orange Basin, South Africa were analyzed for rare earth elements (REEs) and trace elements using inductively coupled plasma-mass spectrometry (ICP-MS). The rare earth elements were profiled in order to determine their relationship to the origin, depositional environment, and age of petroleum source rocks. Most of the rare earth elements identified are of the light REEs series (La, Ce, Pr, Nd, Sm, and Eu) while the trace elements (V, Ni, Mo, and Co) determined are those that are known to have influence on the origin and depositional environment. The results show that the kerogens are mainly of marine origin. The ratios calculated from the concentrations of the elements were able to discriminate marine organic matter from lacustrine organic matter, and also indicate that the organic matter was deposited under anoxic conditions. All the kerogen samples irrespective of the age have similar elemental distribution pattern, indicating a similar genetic origin that could be a reflection of similar organic matter input and depositional environment. The kerogen age has a significant effect on the concentration of the REEs; concentrations of the REEs increase with age. That is, the older the kerogen the greater the content of rare earth elements. Furthermore, the abundance of cerium may be a good indicator of the origin of organic matter. The study also showed that the REEs provide a unique geochemical signature of the kerogens, which can be used for fingerprinting petroleum source rocks.


Kerogen Source rock age Rare earth elements Trace metals Depositional environment, origin 



We are grateful to the Petroleum Agency SA for releasing the samples and data for this study.


  1. Abanda PA, Hannigan RE (2006) Effect of diagenesis on trace element partitioning in shales. Chem Geol 2006(230):42–59CrossRefGoogle Scholar
  2. Adekola SA, Akinlua A, Mangelsdorf K (2012) Organic geochemical evaluation of Cretaceous shale samples from the Orange Basin, South Africa. Appl Geochem 27:1633–1642CrossRefGoogle Scholar
  3. Akinlua A, Ekweozor CM, Ubwa T (2000) New classification scheme of Niger Delta kerogen based on pyrolysis-gas chromatographic data. In: Garg AK et al (eds) Petroleum geochemistry and exploration in the afro-Asian region. R.B. Publishing Corporation, New Delhi, pp 81–86Google Scholar
  4. Akinlua A, Ajayi TR, Jarvie DM, Adeleke BB (2005) Re-appraisal of the application of rock-eval pyrolysis to source rock studies in the Niger Delta. J Pet Geol 28:39–48CrossRefGoogle Scholar
  5. Akinlua A, Torto N (2006) Determination of selected metals in Niger Delta oils by graphite furnace atomic absorption spectrometry. Anal Lett 39:1993–2005CrossRefGoogle Scholar
  6. Akinlua A, Torto N, Ajayi TR, Oyekunle JAO (2007a) Trace metals characterisation of Niger Delta kerogens. Fuel 86:1358–1364CrossRefGoogle Scholar
  7. Akinlua A, Ajayi TR, Adeleke BB (2007b) Organic and inorganic geochemistry of northwestern Niger Delta. Geochem J 41:271–281CrossRefGoogle Scholar
  8. Akinlua A, Torto N, Ajayi TR (2008) Determination of rare earth elements in Niger Delta crude oils by inductively coupled plasma-mass spectrometry. Fuel 87:1469–1477CrossRefGoogle Scholar
  9. Akinlua A, Sigedle A, Buthelezi T, Fadipe OA (2015) Trace element geochemistry of crude oils and condensates from south African basins. Mar Pet Geol 59:286–293CrossRefGoogle Scholar
  10. Akinlua A, Olise FS, Akomolafe AO, McCrindle RI (2016) Rare earth element geochemistry of petroleum source rocks from northwestern Niger Delta. Mar Pet Geol 77:409–417CrossRefGoogle Scholar
  11. Barwise AJG (1990) Role of nickel and vanadium in petroleum classification. Energy Fuel 4:647–652CrossRefGoogle Scholar
  12. Broad D (2004) South Africa activities and opportunities. An unpublished power point presentation to PetroChinaGoogle Scholar
  13. Brown LF, Brown L Jr, Benson JM, Brink G, Doherty JS et al (1996) Sequence stratigraphy in offshore South Africa divergent basins: an atlas on exploration for Cretaceous lowstand traps by SQEKOR (Pty) Ltd. AAPG Stud Geol 41:138–184Google Scholar
  14. Bustin RM (1988) Sedimentology and characteristics of dispersed organic matter. In: tertiary Niger delta: origin of source rocks in deltaic environment. AAPG Bull 72:277–298Google Scholar
  15. Curiale JA (1994) Correlation of oils and source rocks – a conceptual and historical perspective. In: L. B. Magoon, and W. G. Dow, eds., The petroleum system—from source to trap. AAPG Memoir 60: 251–260Google Scholar
  16. Dao-Hui P, Cong-Qiang L, Sheilds-Zhou, Grahm A, Shao-Youn J (2013) Trace and rare earth element geochemistry of black shale and kerogen in the early Cambrian Niutitang formation in Guizhou Province, South China: Constraints for redox environments and origin of metals: Precambrian research 225: 218–229CrossRefGoogle Scholar
  17. Ekweozor CM, Okoye NV (1980) Petroleum source bed evaluation of Tertiary Niger Delta. AAPG Bull 64:1251–1258Google Scholar
  18. Filby RH, van Berkel GJ (1982) Geochemistry of metal complexes on petroleum, source rocks and coals. In Metal complexes in fossil fuels. Filby, R.H. and Branthaver, J.F. (eds.), ACS Symposium Series. 344: 146–153Google Scholar
  19. Galarraga F, Llamas JF, Martinez A, Martinez M, Marquez G, Reategui K (2008) V/Ni ratio as a parameter in palaeoenvironmental characterization of non-mature medium-crude oils from several Latin American basins. J Pet Sci Eng 61:9–14CrossRefGoogle Scholar
  20. Gerrard I, Smith GC (1982) Post-Palaeozoic succession and structure of southwestern African continental margin. In: Watkins JS, Drake CL (eds) Studies in continental margin geology. AAPG Memoir 34: 49–76Google Scholar
  21. Haley BA, Klinkhammer GP, Mcmanus J (2004) Rare earth elements in pore waters of marine sediments. Geochim Cosmochim Acta 68:1265–1279CrossRefGoogle Scholar
  22. Hirner AV (1987) Metals in crude oils, asphaltenes, bitumen and kerogen in Molasse Basin, Southern Germany. In Metal complexes in fossil fuels. Filby, R.H. and Branthaver, J.F. (eds.), ACS Symp Ser 344: 146–153Google Scholar
  23. Hitchon B, Filby RH (1984) Use of trace elements for classification of crude oils into families – example from Alberta, Canada. AAPG Bull 68:838–849Google Scholar
  24. Horsfield B, Di Primio R, Kuhlmann G, Paton AD, van der Spuy D (2007) Insights into the petroleum system evolution of the southern Orange Basin, South Africa. South African J Geol 110:262–263Google Scholar
  25. Jungslager EHA (1999) Petroleum habitat of the Atlantic margin of South Africa. In: Cameron, N.R., Bate, R.H., Clure, V.S. (Eds.), The oil and gas habitats of the South Atlantic. Geological Society of London Special Publication 153: 153–168Google Scholar
  26. Keely BJ, Prowse WG, Maxwell JR (1990) The Triebs hypothesis: an evaluation based on structural studies. Energy Fuel 4:628–634CrossRefGoogle Scholar
  27. Lewan MD, Maynard JB (1982) Factors controlling enrichment of vanadium and nickel in the bitumen of organic sedimentary rocks. Geochim Cosmochim Acta 46:2547–2560CrossRefGoogle Scholar
  28. Lewan MD (1984) Factors controlling the proportionality of vanadium to nickel in crude oils. Geochim Cosmochim Acta 48:2231–2238CrossRefGoogle Scholar
  29. Muntingh A (1993) Geology, prospects in Orange Basin offshore western South Africa. Oil and Gas J 91:105–109Google Scholar
  30. Nakada R, Takahashi Y, Zheng G, Yamamoto Y, Shimizu H (2010) Abundances of rare earth elements in crude oils and their partitions in water. Geochem J 44:411–418CrossRefGoogle Scholar
  31. Nakamoto Y, Ishimaru T, Endo N, Matsusaki K (2004) Determination of vanadium in heavy oils by atomic absorption spectrometry using a graphite furnace coated with tungsten. Anal Sci 20:739–741CrossRefGoogle Scholar
  32. Nwachukwu JI, Chukwura PI (1986) Organic matter of Agbada Formation, Niger Delta, Nigeria. AAPG Bull 70:48–55Google Scholar
  33. Nwachukwu JI, Obiajunwa EI, Obioh IB (2000) Elemental analysis of kerogens from Niger Delta, Nigeria. In: Garg AK et al (eds) Petroleum geochemistry and exploration in the Afro-Asian region, R.B. Publishing Corporation, New Delhi, pp 139–145Google Scholar
  34. Nwachukwu JI, Oluwole AF, Asubiojo OI, Filby RH, Grimm CA, Fitzgerald S (1995) A geochemical evaluation of Niger Delta crude oils. In Geology of Deltas; Oti, M.N., Postma, G. and Balkema, A.A. (eds.), Rotterdam/ Brookfield, 287–300Google Scholar
  35. Paton DA, diPrimio R, Kuhlmann G, van der Spuy D, Horsfield B (2007) Insights into the petroleum system evolution of the southern Orange Basin, South Africa. South African J Geol 110:261–274CrossRefGoogle Scholar
  36. Peters KE, Walters CC, Moldowan JM (2005) The biomarker guide. Biomarkers and isotopes in petroleum exploration and earth history, second ed., vol. 2. Cambridge, pp. 475–1155Google Scholar
  37. Petroleum Agency of South Africa (2005) Brochure 2004/2005: petroleum exploration, information and opportunities, pp 5–17.Google Scholar
  38. Saxby JD (1970) Isolation of kerogen in sediments by chemical methods. Chem Geol 6:173–184CrossRefGoogle Scholar
  39. Sundararaman P, Boreham CJ (1993) Composition of nickel and vanadyl porphyrin distributions of sediments. Geochim Cosmochim Acta 57:1367–1377CrossRefGoogle Scholar
  40. Takeda K, Arikawa Y (2005) Determination of rare earth elements in petroleum by ICP-MS. Bunseki Kagaku 2005 54:939–943CrossRefGoogle Scholar
  41. Udo OT, Ekwere S, Abrakasa S (1992) Some trace metal in selected Niger Delta crude oils: application in oil–oil correlation studies. J Min Geol 28:289–291Google Scholar
  42. Welte DH, Yükler MA, Radke M, Leythaeuser D, Mann U, Ritter U (1983) Organic geochemistry and basin modelling; important tools in petroleum evaluation. In: J. Brooks (Ed) Petroleum geochemistry and exploration of Europe. Geological Society, London Special Publications 12: 237–252Google Scholar

Copyright information

© Saudi Society for Geosciences 2018

Authors and Affiliations

  • Akinsehinwa Akinlua
    • 1
    Email author
  • Solomon Adeniyi Adekola
    • 2
  • Adeyemi Adio Kumolu
    • 1
  1. 1.Department of Chemistry, Fossil Fuels and Environmental GeochemistryObafemi Awolowo UniversityIle-IfeNigeria
  2. 2.Department of GeologyObafemi Awolowo UniversityIle-IfeNigeria

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