Skip to main content
SpringerLink
Log in

Amphibole-rich xenoliths and host alkali basalts: petrogenetic constraints and implications on the recent evolution of the upper mantle beneath Ahaggar (Central Sahara, Southern Algeria)

  • Published:
Contributions to Mineralogy and Petrology Aims and scope Submit manuscript

Abstract

Quaternary basanitic to nephelinitic volcanoes from Tahalra (western Ahaggar, southern Algeria) contain numerous Mg-ilmenite and amphibole-rich inclusions (±olivine, ±salite) and spinel lherzolite (±pargasite) inclusions associated with kaersutite megacrysts. On the basis of petrological, geochemical and Sr isotopic study of representative xenoliths (including a composite nodule defined as a vein cross-cutting peridotite) and lavas, we attribute the series of amphibole-rich xenoliths and megacrysts to segregation under upper mantle conditions from a hydrous high Ti and LREE melt geochemically similar to the Quaternary basanite but isotopically different. Amphibole-rich rocks and megacrysts are the results of magmatic events (less than 40 Ma) probably contemporaneous with the various pre-Quaternary volcanic phases recognized in Ahaggar. The amphibole-rich veins and the Quaternary lavas have a garnet lherzolitic source enriched in REE (7 to 9 times chondritic in LREE, 2 times in HREE). This enrichment probably results from former metasomatic events unrelated to the recent magmatic history. Melts from which these veins precipitated within upper mantle peridotite also account for mantle enrichment processes; they induced a local partial melting and contact metasomatism (pargasitization). The upper mantle beneath the volcanic areas of Ahaggar is veined and hydrous, and consequently lightened: thus, the uplift of basement may be the isostatic response to magmatism and related metasomatism and therefore the result of the Cenozoïc igneous activity.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Allegre CJ, Dupré B, Lambert B, Richard P (1981) The subcontinental versus the sub-oceanic debate — I. Lead-neodynium-strontium isotopes in primary alkali basalts from a shield area: The Ahaggar volcanic suite. Earth Planet Sci Lett 52:85–92

    Google Scholar 

  • Allen JC, Boettcher AL (1978) Amphiboles in andesite and basalt. II. Stability as a function of P-T-f H2O-f O2. Am Mineral 63:1074–1087

    Google Scholar 

  • Bergman SC (1982) Petrogenetic aspects of the alkali basaltic lavas and included megacrysts and nodules from the Lunar Crater volcanic field, Nevada, USA. Thesis, Princeton University

  • Bergman SC, Foland KA, Spera J (1981) On the origin of an amphibole rich vein in a peridotite inclusion from the Lunar Crater volcanic field, Nevada, USA. Earth Planet Sci Lett 56:343–361

    Google Scholar 

  • Best MG (1974) Mantle-derived amphibole within inclusions in alkalic basaltic lavas. J Geophys Res 79:2107–2113

    Google Scholar 

  • Boctor NZ, Boyd FR (1980) Oxide minerals in the Lighobong Kimberlite, Lesotho. Am Mineral 65:631–638

    Google Scholar 

  • Boettcher AL, O'Neil JR (1980) Stable isotope, chemical and petrographic studies of high-pressure amphiboles and micas: evidence for metasomatism in the mantle source regions of alkali basalts and kimberlite. Am J Sci 280A:594–621

    Google Scholar 

  • Boivin PA (1982) Interactions entre magmas basaltiques et manteau supérieur: arguments apportés par les enclaves basiques des basaltes alcalins. Thesis, Université de Clermont

  • Brown C, Girdler RW (1980) Interpretation of African gravity and its implication for the break-up of the continents. J Geophys Res 85:6443–6455

    Google Scholar 

  • Clague DA, Frey FA (1982) Petrology and trace element geochemistry of the Honolulu volcanics, Oahu: implications for the oceanic mantle below Hawaiï. J Petrol 23:447–504

    Google Scholar 

  • Crough ST (1981) Free-air gravity over the Hoggar Massif, North West Africa: evidence for alteration of the lithosphere. Tectonophysics 77:189–202

    Google Scholar 

  • Dankwerth PA, Newton RC (1978) Experimental determination of the spinel peridotite to garnet peridotite reaction in the system MgO-Al2O3-SiO2 in the range 900–1,100° C and Al2O3 isopleths of enstatite in the spinel field. Contrib Mineral Petrol 66:189–201

    Google Scholar 

  • Dupuy C, Dostal J, Dautria JM, Girod M (1986) Geochemistry of spinel peridotite inclusions in basalts from Hoggar, Algeria. J Afr Earth Sci 5:209–215

    Google Scholar 

  • Eggler DH, McCallum ME, Smith CG (1979) Megacrysts assemblages in kimberlite from northern Colorado and southern Wyoming: petrology, geothermometry-barometry and a real distribution. In: Boyd FR, Heyer HOA (eds) The mantle sample: inclusions kimberlites and other volcanics. A G U, Washington, pp 213–226

    Google Scholar 

  • Embey-Isztin A (1976) Amphibolite/lherzolite composite xenolith from Szigliget, north of the lake Balaton, Hungary. Earth Planet Sci Lett 31:297–304

    Google Scholar 

  • Fairhead JD (1979) A gravity link between the domally uplifted cenozoïc centers of north-african rift system anomaly. Earth Planet Sci Lett 42:109–113

    Google Scholar 

  • Feigenson MD, Hofmann AW, Spera FJ (1983) Case studies on the origin of basalt — II. The transition from tholeitic to alkalic volcanism on Kohala volcano, Hawaiï. Contrib Mineral Petrol 84:390–405

    Google Scholar 

  • Frey FA, Prinz MA (1978) Ultramafic inclusions from San Carlos Arziona: petrologic and geochemical data bearing on their petrogenesis. Earth Planet Sci Lett 38:129–76

    Google Scholar 

  • Frey FA, Green DH, Roys D (1978) Integrated models for basalt petrogenesis: a study of quartz tholeites to olivine melilitites from South Eastern Australia utilizing geochemical and experimental petrological data. J Petrol 19:463–513

    Google Scholar 

  • Girod M (1971) Le massif volcanique de l'Atakor (Hoggar, Sahara algerien). Edit CNRS-CRZA 2797, pp 155

  • Girod M (1976) Le volcanisme récent. In: Fabre J (ed) Introduction à la géologie du Sahara algérien et de ses régions voisines. SNED Alger, pp 342–364

    Google Scholar 

  • Girod M, Dautria JM, Degiovanni R (1981) A first insight into the constitution of the Upper-Mantle under the Hoggar area (Southern Algeria): the Iherzolite xenoliths in the alkali-basalts. Contrib Mineral Petrol 77:66–73

    Google Scholar 

  • Green DH, Sobolev NV (1975) Coexisting garnets and ilmenites synthetized at high pressure from pyrolite and olivine basanite and their significance for kimberlitic assemblages. Contrib Mineral Petrol 50:217–229

    Google Scholar 

  • Haggerty SE (1975) The chemistry and genesis of opaque minerals in kimberlites. Phys Chem Earth 9:295–503

    Google Scholar 

  • Haggerty SE, Hardie RB, McMahon BM (1979) The mineral chemistry of ilmenite nodule associations from the Monastery diatreme. In: Boyd FR, Meyer HOA (eds) The mantle sample. Proceedings of the 2nd International Kimberlite Conference, vol 2. American Geophysics Union, Washington DC, pp 249–256

    Google Scholar 

  • Irving AJ (1980) Petrology and geochemistry of composite ultramafic xenoliths in alkalic basalts and implications for magmatic processes within the mantle. Am J Sci 280-A: 389–426

    Google Scholar 

  • Irving AJ, Frey FA (1984) Trace element abundances in megacrysts and their host basalts: constraints on partition coefficients and megacryst genesis. Geochim Cosmochim Acta 48:1201–1221

    Google Scholar 

  • Jackson ED (1971) The origin of ultramafic rocks by cumulus processes. Fortschr Mineral 48:128–174

    Google Scholar 

  • Jagoutz E, Palme H, Baddenhausen H, Blum K, Cendales M, Dreibus G, Spettel B, Lorenz V, Wanke H (1979) The abundance of major, minor and trace elements in the earth's mantle as derived from primitive ultramafic nodules. In: Merill RB (ed) Early solar system and lunar regolith, Proceedings of the 10th Lunar Planet Science Conference. Houston, Tx, pp 2031–2050

  • Kramers JD, Roddick JCM, Dawson JB (1983) Trace element and isotope studies on veined, metasomatic and “Marid” xenoliths from Bulfontein, South Africa. Earth Planet Sci Lett 65:90–106

    Google Scholar 

  • Leake BE (1978) Nomenclature of amphiboles. Am Mineral 63:1023–1052

    Google Scholar 

  • Leblanc M, Dautria JM, Girod M (1982) Magnesian ilmenitite xenoliths in a basanite from Tahalra, Ahaggar (Southern Algeria). Contrib Mineral Petrol 79:347–354

    Google Scholar 

  • Liotard JM, Boivin P, Cantagrel JM, Dupuy C (1983) Mégacristaux d'amphibole et basaltes alcalins associés. Problèmes de leurs relations pétrogénétiques et géochimiques. Bull Mineral 106:451–464

    Google Scholar 

  • Lloyd FR, Bailey DK (1975) Light element metasomatism of the continental mantle; the evidence and consequences. Phys Chem Earth 9:389–416

    Google Scholar 

  • Menzies MA (1983) Mantle ultramafic xenoliths in alkaline magmas: Evidences for mantle heterogeneity modified by magmatic activity, In: Hawkesworth CJ, Norry MJ (eds) Continental basalts and mantle xenoliths. Shiva, Cheshire

    Google Scholar 

  • Menzies MA, Murthy VR (1980) Nd and Sr isotope geochemistry of hydrous mantle nodules and their host alkali basalts: implications for local heterogeneities in metasomatically veined mantle. Earth Planet Sci Lett 46:323–334

    Google Scholar 

  • Menzies M, Kempton P, Dungan M (1985) Interaction of continental lithosphere and asthenospheric melts below the Geronimo volcanic field, Arizona, USA. J Petrol 26:663–693

    Google Scholar 

  • Mercier JC (1976) Natural peridotites: chemical and rheological heterogeneity of the upper mantle. PhD, University of New York Stony Brook, USA

    Google Scholar 

  • Mercier JC (1980) Single pyroxene thermobarometry. Tectonophysics 70:1–37

    Google Scholar 

  • Miller C (1982) Geochemical constants on the origin of xenoliths bearing alkali basaltic rocks and megacrysts from the Hoggar, Central Sahara. Geochem J 16:225–236

    Google Scholar 

  • Millhollen A, Irving AJ, Wyllie PJ (1974) Melting interval of peridotite with 5.7 per cent water to 30 kilobars. J Geol 82:575–587

    Google Scholar 

  • Mitchell RH (1973) Magnesian ilmenite and its role in kimberlite petrogenesis. J Geol 81:301–311

    Google Scholar 

  • Mitchell RH (1978) Manganoan magnesian ilmenite and titanian clinohumite from the Jacupiranga carbonatite, Sao Paulo, Brazil. Am Mineral 63:544–547

    Google Scholar 

  • Obata M (1976) The solubility of Al2O3 in orthopyroxenes in spinel and plagioclase peridotites and spinel pyroxenites. Am Mineral 61:804–816

    Google Scholar 

  • Pasteris JD (1980) The significance of groundmass ilmenite and megacrysts ilmenite in kimberlites. Contrib Mineral Petrol 75:315–325

    Google Scholar 

  • Presnall DC (1976) Alumina content of enstatite as a geobarometer for plagioclase and spinel lherzolite. Am Mineral 61:582–589

    Google Scholar 

  • Reid JB, Geoffrey AW (1978) Oceanic mantle beneath the southern Rio Grande rift. Earth Planet Sci Lett 41:303–316

    Google Scholar 

  • Roden MF, Frey FA, Francis DM (1984) Am example of consequent mantle metasomatism in peridotite inclusions from Nunivak island, Alaska. J Petrol 25:546–577

    Google Scholar 

  • Roeder PL, Campbell IH, Jamieson HE (1979) A re-evaluation of the olivine-spinel geothermometer. Contrib Mineral Petrol 68:325–334

    Google Scholar 

  • Shaw DM (1970) Trace element fractionation during anatexis. Geochim Cosmochim Acta 34:337–343

    Google Scholar 

  • Sun SS, Hanson GN (1975) Origin of Ross Island basanitoids and limitations upon the heterogeneity of mantle source for alkali basalts and nephelinites. Contrib Mineral Petrol 52:77–106

    Google Scholar 

  • Wass SY (1979) Fractional crystallisation in the mantle of late stage kimberlitic liquids — evidence in xenoliths from the Kiama area, NSW Australia. In: Boyd FR, Meyer HOA (eds) The mantle sample: inclusions in kimberlite and other volcanics. AGU, Washington, pp 266–373

    Google Scholar 

  • Wass SY, Rogers NW (1980) Mantle metasomatism — precursor to continental alkaline volcanism. Geochim Cosmochim Acta 44:1811–1823

    Google Scholar 

  • Watson EB (1982) Melt infiltrations and magma evolution. Geology 10:236–240

    Google Scholar 

  • Wells PRA (1977) Pyroxene thermometry in simple and complex systems. Contrib Mineral Petrol 62:129–139

    Google Scholar 

  • Wilshire HG, Nielson Pike JE, Meyers CE, Schwarzman EC (1980) Amphibole rich veins in Iherzolite xenoliths, Dish Hill and Deadman Lake, California. Am J Sci 280-A: 576–593

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Laboratoire de Pétrologie, U.S.T.L., Place E. Bataillon, F-34060, Montpellier, France

    J. M. Dautria, J. M. Liotard, N. Cabanes & M. Girod

  2. Centre Géologique et Géophysique, U.S.T.L., F-34060, Montpellier, France

    J. M. Dautria, N. Cabanes, M. Girod & L. Briqueu

Authors
  1. J. M. Dautria
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. J. M. Liotard
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. N. Cabanes
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. M. Girod
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. L. Briqueu
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Dautria, J.M., Liotard, J.M., Cabanes, N. et al. Amphibole-rich xenoliths and host alkali basalts: petrogenetic constraints and implications on the recent evolution of the upper mantle beneath Ahaggar (Central Sahara, Southern Algeria). Contr. Mineral. and Petrol. 95, 133–144 (1987). https://doi.org/10.1007/BF00381263

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00381263

Keywords

Search

Navigation