Olivine chemistry from Cameroon: evidence of carbonate metasomatism along the ocean-continental boundary of the Cameroon volcanic line

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We report olivine chemistry in basaltic rocks from the Mt. Cameroon Volcanic area, which is used as a proxy to understand mantle and early igneous processes along the ocean-continent segment of the Cameroon Volcanic Line. Most primitive olivine phenocrysts in this study have forsterite contents of 86–87.5%. Their Li concentrations are below 3.5 ppm and occur in similar concentrations in all the samples. Ni has a large range in concentration, with some values as low as 742 ppm and others as high as 2500 ppm. The concentrations of Ca are in the range 2666–3755 ppm and that of Mn in the range 1283–2358 ppm. Olivine Ca/Al ratios are higher than those from both MORB and some within plate settings (e.g., Hawaii). Bulk rocks have low SiO2 (39.3–40.4 wt%) and high CaO/Al2O3 (0.72–1.03). The high olivine Ca/Al ratios, low bulk rocks SiO2 contents, and high bulk rocks CaO/Al2O3 ratios require a peridotite mantle source modified by carbonate-rich fluids. The plot of bulk rocks SiO2 vs. CaO similarly indicates CO2- enrichment. This metasomatic reaction may be regarded as the main source of volcanic hazardous CO2 along the CVL; such as in lakes Nyos and Monoun in 1986 and 1984 respectively, where approximately 2000 human and countless animal deaths were recorded.

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  1. Adams AN, Wiens DA, Nyblade AA, Euler GG, Shore PJ, Tibi R (2015) Lithospheric instability and the source of the Cameroon volcanic line: evidence from Rayleigh wave phase velocity tomography. J Geophys Res 120:1708–1727

  2. Ammannati E, Jacob DE, Avanzinelli R, Foley SF, Conticelli S (2016) Low Ni olivine in silica-undersaturated ultrapotassic igneous rocks as evidence for carbonate metasomatism in the mantle. Earth Planet Sci Lett 444:64–74

  3. Asaah AN, YokoyamaT AFT, Usui T, Kuritani T, Wirmvem MJ, Iwamori H, Fozing EM, Tamen J, Mofor GZ (2015) Geochemistry of lavas from maar-bearing volcanoes in the Oku volcanic Group of the Cameroon Volcanic Line. Chem Geol 406:55–69

  4. Bohrson WA, Spera FJ (2001) Energy-constrained open system magmatic processes II: application of energy-constrained assimilation-fractional crystallization (EC-AFC) model to magmatic systems. J Petrol 42:1019–1041

  5. Bougault H, Hekinian R (1974) Rift valley in the Atlantic Ocean near 36 50′ N: petrology and geochemistry of basaltic rocks. Earth Planet Sci Lett 24:249–261

  6. Burke K (2001) Origin of the Cameroon line of volcano capped swells. J Geol 109:349–362

  7. Cox K (1980) A model for flood basalt volcanism. J Petrol 21:629–650

  8. Dasgupta R, Hirschmann MM, Smith ND (2007) Partial melting experiments of peridotite+ CO2 at 3 GPa and genesis of alkalic ocean island basalts. J Petrol 48:2093–2124

  9. De Hoog JC, Gall L, Cornell DH (2010) Trace-element geochemistry of mantle olivine and application to mantle petrogenesis and geothermobarometry. Chem Geol 270:196–215

  10. De Plaen R, Bastow I, Chambers E, Keir D, Gallacher R, Keane J (2014) The development of magmatism along the Cameroon volcanic line: evidence from seismicity and seismic anisotropy. Journal of geophysical research. Solid Earth 119:4233–4252

  11. Déruelle B, N’ni J, Kambou R (1987) Mount Cameroon: an active volcano of the Cameroon line. J Afr Earth Sci 6:197–214

  12. Déruelle B, Ngounouno I, Demaiffe D (2007) The ‘Cameroon Hot Line’ (CHL): a unique example of active alkaline intraplate structure in both oceanic and continental lithospheres. Compt Rendus Geosci 339:589–600

  13. Ebinger C, Sleep N (1998) Cenozoic magmatism throughout East Africa resulting from impact of a single plume. Nature 295:788–791

  14. Elsheikh AA, Gao SS, Liu KH (2014) Formation of the Cameroon volcanic line by lithospheric basal erosion: insight from mantle seismic anisotropy. J Afr Earth Sci 100:96–108

  15. Fitton J (1987) The Cameroon line, West Africa: a comparison between oceanic and continental alkaline volcanism. Geol Soc Lond Spec Publ 30:273–291

  16. Fitton J, Dunlop H (1985) The Cameroon line, West Africa, and its bearing on the origin of oceanic and continental alkali basalt. Earth Planet Sci Lett 72:23–38

  17. Fitton J, Kilburn C, Thirlwall M, Hughes D (1983) 1982 eruption of Mount Cameroon, West Africa. Nature 306:327–332

  18. Foley SF, Jacob DE, O’Neill HSC (2011) Trace element variations in olivine phenocrysts from Ugandan potassic rocks as clues to the chemical characteristics of parental magmas. Contrib Mineral Petrol 162:1–20

  19. Foley SF, Prelevic D, Rehfeldt T, Jacob DE (2013) Minor and trace elements in olivines as probes into early igneous and mantle melting processes. Earth Planet Sci Lett 363:181–191

  20. France LCG, Kornprobst J, Dallai L, Vannucci R, Grégoire M, Bertrand H, Boivin P (2015) Mantle refertilization and magmatism in old orogenic regions: the role of late-orogenic pyroxenites. Lithos 232:49–75

  21. Frey F, Green D, Roy S (1978) Integrated models of basalt petrogenesis: a study of quartz tholeiites to olivine melilitites from south eastern Australia utilizing geochemical and experimental petrological data. J Petrol 19:463–513

  22. Gaeta M, Di Rocco T, Freda C (2009) Carbonate assimilation in open magmatic systems: the role of melt-bearing skarns and cumulate-forming processes. J Petrol 50:361–385

  23. Geiger H, Barker AK, Troll VR (2016) Locating the depth of magma supply for volcanic eruptions, insights from Mt. Cameroon. Sci Report 6:1–10

  24. Halliday AN, Dickin AP, Fallick AE, Fitton JG (1988) Mantle dynamics: a Nd, Sr, Pb and O isotopic study of the Cameroon line volcanic chain. J Petrol 29:181–211

  25. Halliday AN, Davidson JP, Holden P, DeWolf CP, Lee DC, Fitton JG (1990) Trace element fractionation in plumes and the origin of HIMU mantle beneath the Cameroon line. Nature 347:523–528

  26. Hawkesworth CJ, Kemp AIS (2006) Evolution of the continental crust. Nature 443.

  27. Herzberg C (2011) Identification of source lithology in the Hawaiian and Canary Islands: implications for origins. J Petrol 52:113–146

  28. Herzberg C, Asimow PD (2008) Petrology of some oceanic island basalts: PRIMELT2. XLS software for primary magma calculation. Geochem Geophys Geosyst 9.

  29. Higuchi H, Nagasawa H (1969) Partition of trace elements between rock-forming minerals and the host volcanic rocks. Earth Planet Sci Lett 7:281–287

  30. Hofmann AW (1988) Chemical differentiation of the earth: the relationship between mantle, continental crust, and oceanic crust. Earth Planet Sci Lett 90:297–314

  31. Ionov DA, Seitz HM (2008) Lithium abundances and isotopic compositions in mantle xenoliths from subduction and intra-plate settings: mantle sources vs. eruption histories. Earth Planet Sci Lett 266:316–331

  32. Jarosewich E (2002) Smithsonian microbeam standards. J Res Natl Inst Stand Technol 107:681–686

  33. Jeffcoate A, Elliott T, Kaesmann SA, Ionov D, Cooper K, Brooker R (2007) Li isotope fractionation in peridotites and mafic melts. Geochim Cosmochim Acta 71:202–218

  34. Jochum KP, Stoll B, Herwig K, Willbold M, Hofmann AW, Amini M, Aarburg S, Abouchami W, Hellebrand E, Mocek B (2006) MPI-DING reference glasses for in situ microanalysis: new reference values for element concentrations and isotope ratios. Geochem Geophys Geosyst 7.

  35. Jochum KP, Weis U, Stoll B, Kuzmin D, Yang Q, Raczek I, Jacob DE, Stracke A, Birbaum K, Frick DA (2011) Determination of reference values for NIST SRM 610–617 glasses following ISO guidelines. Geostand Geoanal Res 35:397–429

  36. Kamgang P, Chazot G, Njonfang E, Ngongang NBT, Tchoua FM (2013) Mantle sources and magma evolution beneath the Cameroon Volcanic Line: geochemistry of mafic rocks from the Bamenda Mountains (NW Cameroon). Gondwana Res 24:727–741

  37. King SD, Anderson DL (1998) Edge-driven convection. Earth Planet Sci Lett 160:289–296

  38. King SD, Ritsema J (2000) African hot spot volcanism: small-scale convection in the upper mantle beneath cratons. Science 290:1137–1140

  39. Kling GW, Clark MA, Wagner GN, Compton HR, Humphrey AM, Devine JD, Evans WC, Lockwood JP, Tuttle ML, Koenigsberg EJ (1987) The 1986 Lake Nyos gas disaster in Cameroon, West Africa. Science 236:169–175

  40. Klock W, Palme H (1988) Partitioning of siderophile and chalcophile elements between sulfide, olivine, and glass in a naturally reduced basalt from Disko Island, Greenland, Lunar and Planetary Science Conference Proceedings, pp 471–483

  41. Le Maitre RW, Streckeisen A, Zanettin B, Le Bas MJ, Bonin P, Bateman P, Bellieni G, Dudek A, Efremova S, Keller J, Lameyre J, Sabine PA, Schmid R, Sørensen H, Woolley AR (2002) Igneous rocks: a classification of and glossary of terms. Recommendations of the International Union of Geological Sciences (IUGS), Subcommission on the Systematics of Igneous Rocks, vol 2. Cambridge University Press, Cambridge, UK, p 236

  42. Lee DC, Halliday AN, Fitton JG, Poli G (1994) Isotopic variations with distance and time in the volcanic islands of the Cameroon line: evidence for a mantle plume origin. Earth Planet Sci Lett 123:119–138

  43. Libourel G (1999) Systematics of calcium partitioning between olivine and silicate melt: implications for melt structure and calcium content of magmatic olivines. Contrib Mineral Petrol 136:63–80

  44. Marzoli A, Piccirillo E, Renne P, Bellieni G, Iacumin M, Nyobe J, Tongwa A (2000) The Cameroon Volcanic Line revisited: petrogenesis of continental basaltic magmas from lithospheric and asthenospheric mantle sources. J Petrol 41:87–109

  45. Mathieu L, Kervyn M, Ernst GG (2011) Field evidence for flank instability, basal spreading and volcano-tectonic interactions at Mt Cameroon, West Africa. Bull Volcanol 73:851–867

  46. Matzen AK, Baker MB, Beckett JR, Stolper EM (2013) The temperature and pressure dependence of nickel partitioning between olivine and silicate melt. J Petrol 54:2521–2545

  47. McDonough WF (1990) Constraints on the composition of the continental lithospheric mantle. Earth Planet Sci Lett 101:1–18

  48. Meyers JB, Rosendahl BR, Harrison CGA, Ding ZD (1998) Deep-imaging seismic and gravity results from the offshore Cameroon volcanic line, and speculation of African hotlines. Tectonophysics 284:31–63

  49. Milelli L, Fourel L, Jaupart C (2012) A lithospheric instability origin for the Cameroon Volcanic Line. Earth Planet Sci Lett 335:80–87

  50. Nakagawa M, Wada K, Wood CP (2002) Mixed magmas, mush chambers and eruption triggers: evidence from zoned clinopyroxene phenocrysts in andesitic scoria from the 1995 eruptions of Ruapehu volcano, New Zealand. J Petrol 43:2279–2303

  51. Ngako V, Njonfang E, Nnange JM (2006) The North–South Paleozoic to quaternary trend of alkaline magmatism from Niger–Nigeria to Cameroon: complex interaction between hotspots and Precambrian faults. J Afr Earth Sci 45:241–256

  52. Ngwa CN, Hansteen TH, Devey CW, Van der Zwan FM, Suh CE (2017) Origin and evolution of primitive melts from the Debunscha Maar, Cameroon: consequences for mantle source heterogeneity within the Cameroon Volcanic Line. Lithos 288–289:326–337

  53. Niu Y, Wilson M, Humphreys ER, O’Hara MJ (2011) The origin of intra-plate ocean island basalts (OIB): the lid effect and its geodynamic implications. J Petrol 52:1443–1468

  54. Njilah IK, Amidou M, Robert T, Benjamin N (2013) Sr-Nd-Pb isotopic studies of lavas of Mt. Oku volcano, north West Cameroon: a case involving HIMU, depleted and enriched mantle sources. J Geol Min Res 5:124–135

  55. Nkouandou OF, Temdjim R (2011) Petrology of spinel lherzolite xenoliths and host basaltic lava from Ngao Voglar volcano, Adamawa Massif (Cameroon Volcanic Line, West Africa): equilibrium conditions and mantle characteristics. J Geosci 56:375–387

  56. Palme H, O’Neill HSC (2014) Cosmochemical estimates of mantle composition. In: Treatise on geochemistry, 2nd edn, 3, pp 1–39

  57. Papike JJ (1987) Chemistry of the rock-forming silicates: ortho, ring, and single-chain structures. Rev Geophys 25(7):1483–1526

  58. Piochi M, Ayuso AR, De Vivo B, Somma R (2006) Crustal contamination and crystal entrapment during polybaric magma evolution at Monte Somma-Vesuvius volcano, Italy: geochemical and Sr isotope evidence. Lithos 86:303–329

  59. Pouchou JL, Pichoir F (1991) Quantitative analysis of homogeneous or stratified microvolumes applying the model ‘PAP’. In: Heinrich KFJ, Newbury DE (eds) Electron probe quantitation. Plenum Press, New York, pp 31–75

  60. Prelević D, Jacob DE, Foley SF (2013) Recycling plus: a new recipe for the formation of Alpine–Himalayan orogenic mantle lithosphere. Earth Planet Sci Lett 362:187–197

  61. Reusch AM, Nyblade AA, Tibi R, Wiens DA, Shore PJ, Bekoa A, Tabod CT, Nnange JM (2011) Mantle transition zone thickness beneath Cameroon: evidence for an upper mantle origin for the Cameroon Volcanic Line. Geophys J Int 187:1146–1150

  62. Rudnick RL, Fountain DM (1995) Nature and composition of the continental crust: a lower crustal perspective. Rev Geophys 33:267–309

  63. Sakuyama M (1979) Evidence of magma mixing: petrological study of Shirouma-Oike calc-alkaline andesite volcano, Japan. J Volcanol Geotherm Res 5:179–208

  64. Sakuyama M (1981) Petrological study of the Myoko and Kurohime volcanoes, Japan: crystallization sequence and evidence for magma mixing. J Petrol 22:553–583

  65. Sato H, Aramaki S, Kusakabe M, Hirabayashi J, Sano Y, Nojiri Y, Tchoua F (1990) Geochemical difference of basalts between polygenetic and monogenetic volcanoes in the central part of the Cameroon Volcanic Line. Geochem J 24:357–370

  66. Shellnutt J, Lee TY, Torng PK, Yang CC, Lee YH (2016) Late Cretaceous intraplate silicic volcanic rocks from the Lake Chad region: an extension of the Cameroon volcanic line? Geochem Geophys Geosyst 17:2803–2824

  67. Sigurdsson H, Devine JD, Tchoua FM, Pressor TS, Pringle MKW, Evans WC (1987) Origin of the lethal gas burst from Lake Monoun, Cameroun. J Volcanol Geotherm Res 31:1–16

  68. Sobolev AV, Hofmann AW, Sobolev SV, Nikogosian IK (2005) An olivine-free mantle source of Hawaiian shield basalts. Nature 434:590–597

  69. Sobolev AV, Hofmann AW, Kuzmin DV, Yaxley GM, Arndt NT, Chung SL, Danyushevsky LV, Elliott T, Frey FA, Garcia MO (2007) The amount of recycled crust in sources of mantle-derived melts. Science 316:412–417

  70. Straub SM, LaGatta AB, Pozzo MD, Lillian A, Langmuir CH (2008) Evidence from high-Ni olivines for a hybridized peridotite/pyroxenite source for orogenic andesites from the central Mexican Volcanic Belt. Geochem Geophys Geosyst 9.

  71. Suh C, Ayonghe S, Sparks R, Annen C, Fitton J, Nana R, Luckman A (2003) The 1999 and 2000 eruptions of Mount Cameroon: eruption behaviour and petrochemistry of lava. Bull Volcanol 65:267–281

  72. Suh C, Luhr J, Njome M (2008) Olivine-hosted glass inclusions from scoriae erupted in 1954–2000 at Mount Cameroon volcano, West Africa. J Volcanol Geotherm Res 169:1–33

  73. Teitchou M, Grégoire M, Temdjim R, Ghogomu R, Ngwa C, Aka F (2011) Mineralogical and geochemical fingerprints of mantle metasomatism beneath Nyos volcano (Cameroon volcanic line). Geol Soc Am Spec Pap 478:193–210

  74. Thompson RN, Gibson AA (2000) Transient high temperatures in mantle plume heads inferred from magnesian olivines in Phanerozoic picrites. Nature 407:502–506

  75. Trela J, Vidito C, Gazel E, Herzberg C, Class C, Whalen W, Jicha B, Bizimis M, Alvarado GE (2015) Recycled crust in the Galápagos Plume source at 70 Ma: implications for plume evolution. Earth Planet Sci Lett 425:268–277

  76. Tsafack JPF, Wandji P, Bardintzeff JM, Bellon H, Guillou H (2009) The Mount Cameroon stratovolcano (Cameroon Volcanic Line, Central Africa): petrology, geochemistry, isotope and age data. Geochem Mineral Petrol 47:65–78

  77. Umino S, Horio A (1998) Multistage magma mixing revealed in Phenocryst zoning of the Yunokuchi pumice Akagi volcano, Japan. J Petrol 39:101–124

  78. Walter MJ (1998) Melting of garnet peridotite and the origin of komatiite and depleted lithosphere. J Petrol 39:29–60

  79. Wandji P, Tsafack J, Bardintzeff J, Nkouathio D, Dongmo AK, Bellon H, Guillou H (2009) Xenoliths of dunites, wehrlites and clinopyroxenites in the basanites from Batoke volcanic cone (Mount Cameroon, Central Africa): petrogenetic implications. Mineral Petrol 96:81–98

  80. Wedepohl KH (1995) The composition of the continental crust. Geochim Cosmochim Acta 59:1217–1232

  81. Weiss Y, Class C, Goldstein SL, Hanyu T (2016) Key new pieces of the HIMU puzzle from olivines and diamond inclusions. Nature 537:666–670

  82. Yamgouot FN, Déruelle B, Mbowou IBG, Ngounouno I, Demaiffe D (2015) Geochemistry of the volcanic rocks from Bioko Island (“Cameroon Hot Line”): evidence for plume-lithosphere interaction. Geosci Front 7:743–757

  83. Yokoyama T, Kusakabe M, Nakamura E (2007) Plume-lithosphere interaction beneath Mt. Cameroon volcano, West Africa: constraints from 238U–230Th–226Ra and Sr-Nd–Pb isotope systematics. Geochim Cosmochim Acta 71:1835–1854

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This contribution is part of an M.Sc thesis of Bless N. Shu at the University Bamenda in Cameroon, under a Schlumberger Faculty for the Future postdoctoral fellowship awarded to Caroline N. Ngwa at the Geomar Helmholtz Center for Ocean Research Kiel, Germany. Our many thanks also go to Mario Thöner, Matthias Frische, and Dagmar Rau of Geomar, for analytical assistance. In addition, we acknowledge the constructive comments and suggestions of two anonymous reviewers which helped us to considerably improve this manuscript. We are also grateful to the editors for the diligent editorial handling of the manuscript.

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Ngwa, C.N., Shu, B.N., Mbassa, B.J. et al. Olivine chemistry from Cameroon: evidence of carbonate metasomatism along the ocean-continental boundary of the Cameroon volcanic line. Miner Petrol (2019) doi:10.1007/s00710-019-00689-5

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  • Olivine chemistry
  • Metasomatism
  • Cameroon volcanic line