Skip to main content
Log in

Mineralogical and geochemical investigation of layered chromitites from the Bracco–Gabbro complex, Ligurian ophiolite, Italy

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

Abstract

The Bracco–Gabbro Complex (Internal Liguride ophiolite), that intruded subcontinental mantle peridotite, contains layers of chromitite that are associated with ultramafic differentiates. The chromitites and disseminated chromites in the ultramafics have Al contents similar to the Al-rich podiform chromitites [0.40 < Cr# = Cr/(Cr + Al) < 0.55]. TiO2 contents of the chromitites are unusually high and range up to 0.82 wt%. The calculated Al2O3 and TiO2 content of the parental melt suggest that the melt was a MORB type. Geothermobarometrical calculations on few preserved silicate inclusions revealed formation temperatures between 970 and 820 °C under a relatively high oxygen fugacity (ΔlogfO2 at +2.0–2.4). Chromitites were altered during the post-magmatic tectono-metamorphic uplift and the final exposure at the seafloor, as evidenced by the formation of ferrian chromite. The PGE contents of the chromitites and associated ultramafics are unusually low (PGEmax 83 ppb). The chondrite-normalized PGE spidergrams show positive PGE patterns and to some extent similarities with the typical trend of stratiform chromitites. No specific PGM have been found but low concentrations of PPGE (Rh, Pt, and Pd) have been detected in the sulphides that occur interstitially to or enclosed in chromite. Recently, it has been shown that the Internal Liguride gabbroic intrusions have formed by relatively low degrees of partial melting of the asthenospheric mantle. We conclude that the low degree of partial melting might be the main factor to control the unusual low PGE contents and the rather unique PGE distribution in the Bracco chromitites.

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

Access this article

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

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8

Similar content being viewed by others

References

  • Ahmed AH, Arai AS (2002) Unexpectedly high PGE chromitite from the deeper mantle section of the northern Oman ophiolite and its tectonic implications. Contrib Mineral Petrol 143:263–278

    Article  Google Scholar 

  • Arai S (1992) Chemistry of chromian spinel in volcanic rocks as a potential guide to magma chemistry. Mineral Mag 56:173–184

    Article  Google Scholar 

  • Arai S (1997) Control of wall-rock composition on the formation of podiform chromitites as a result of magma/peridotite interaction. Resour Geol 47:177–187

    Google Scholar 

  • Arai S, Uesugi J, Ahmed AH (2004) Upper crustal podiform chromitite from the northern Oman ophiolite as the stratigraphically shallowest chromitite in ophiolite and its implication for Cr concentration. Contrib Mineral Petrol 147:145–154

    Article  Google Scholar 

  • Augé T (1987) Chromite deposits in the northwestern Oman ophiolite: mineralogical constraints. Miner Depos 22:1–10

    Article  Google Scholar 

  • Ballhaus C, Berry RF, Green DH (1991) High pressure experimental calibration of the olivine—orthopyroxene–spinel oxygen geobarometer: implications for the oxidation of the mantle. Contrib Mineral Petrol 107:27–40

    Article  Google Scholar 

  • Barnes SJ, Roeder PL (2001) The range of spinel composition in terrestrial mafic and ultramafic rocks. Contrib Mineral Petrol 42:2279–2302

    Google Scholar 

  • Barnes SJ, Naldrett AJ, Gorton MP (1985) The origin of the fractionation of the platinum-group elements in terrestrial magmas. Chem Geol 53:303–323

    Article  Google Scholar 

  • Barrett JJ, Spooner EFC (1977) Ophiolitic breccias associated with allochthonous oceanic crustal rocks in the East Ligurian Apennines, Italy—A comparison with observations from rifted oceanic ridges. Earth Planet Sci Lett 35:79–91

    Article  Google Scholar 

  • Bezzi A, Piccardo GB (1970) Studi petrografici sulle formazioni ofiolitiche della Liguria. Riflessioni sulla genesi dei complessi ofiolitici in ambiente appenninico e alpino. Rend Soc It Mineral Petrol 26:1–42

    Google Scholar 

  • Bezzi A, Piccardo GB (1971) Structural features of the Ligurian ophiolites: petrologic evidence for the “oceanic” floor of northern Apennines geosyncline. Mem Soc Geol It 10:53–63

    Google Scholar 

  • Brigo L, Ferrario A (1974) Le mineralizzazioni nelle ofioliti della Liguria Orientale. Rend Soc It Mineral Petrol 30:305–316

    Google Scholar 

  • Cabella R, Gazzotti M, Lucchetti G (1997) Loveringite and baddeleyite in layers of chromian spinel from the Bracco ophiolitic unit, Northern Apennines, Italy. Can Mineral 35:899–908

    Google Scholar 

  • Cabella R, Garuti G, Oddone M, Zaccarini F (2002) Platinum-group element geochemistry in chromitite and related rocks of the Bracco gabbro complex (Ligurian Ophiolites, Italy). 9th Intern Platinum Symp, Abstract with Program, Billings, Montana, pp 69–72

  • Cawthorn RG (1999) Geological models for platinum group metal mineralization in the Bushveld Complex. S Afr J Sci 95:490–498

    Google Scholar 

  • Cawthorn RG, Walraven F (1998) Emplacement and crystallization time for the Bushveld complex. J Petrol 39:1669–1687

    Article  Google Scholar 

  • Çina A, Neziraj A, Karaj N, Johan Z, Ohnenstetter M (2002) PGE mineralization related to Albanian ophiolitic complex. Geol Carpat 53 (available online)

  • Cortesogno L, Lucchetti G, Penco AM (1975) Preorogenic metamorphic and tectonic evolution of the ophiolite mafic rocks (Northern Appenine and Tuscany). Rend Soc Ital Mineral Petrol 94:291–327

    Google Scholar 

  • Cortesogno L, Galbiati B, Principi G (1981) Descrizione dettagliata di alcuni caratteristici affi oramenti di brecce serpentinitiche della Liguria orientale ed interpretazione in chiave geodinamica. Ofioliti 6:47–76

    Google Scholar 

  • Cortesogno L, Galbiati B, Principi G (1987) Note alla “Carta geologica delle ofioliti del Bracco” e ricostruzione della paleogeografia Giurassico, Cretacica. Ofioliti 12:261–342

    Google Scholar 

  • Dick HJB, Bullen T (1984) Chromian spinel as a petrogenetic indicator in abyssal and alpine-type peridotites and spatially associated lavas. Contrib Mineral Petrol 85:54–76

    Article  Google Scholar 

  • Dilek Y, Furnes H (2011) Ophiolite genesis and global tectonics: geochemical and tectonic fingerprinting of ancient oceanic lithosphere. Bull Geol Soc Am 123:387–411

    Article  Google Scholar 

  • Droop GTR (1987) A general equation for estimating Fe3+ in ferromagnesian silicates and oxides from microprobe analysis, using stoichiometric criteria. Mineral Mag 51:431–437

    Article  Google Scholar 

  • Economou–Eliopoulos M (1996) Platinum–group element distribution in chromite ores from ophiolite complexes: implications for their exploration. Ore Geol Rev 11:363–381

    Article  Google Scholar 

  • Escayola M, Garuti G, Zaccarini F, Proenza JA, Bedard J, Van Staal C (2011) Chromitite and platinum-group element mineralization at Middle Arm Brook, central Advocate ophiolite complex (Baie Verte peninsula, Newfoundland, Canada). Can Mineral 49:1523–1547

    Article  Google Scholar 

  • Fabries J (1979) Spinel-olivine geothermometry in peridotites from ultramafic complexes. Contrib Mineral Petrol 69:329–336

    Article  Google Scholar 

  • Ferrario A, Garuti G (1988) Platinum-group minerals in chromite-rich horizons of the Niquelândia complex (Central Goiás, Brazil). In: Prichard HM, Potts PJ, Bowels JFW, Cribb SJ (eds) Proceedings of geo-platinum 87 symposium, Milton Keyes 1987, Elsevier, pp 261–272

  • Ferreira Filho CF, Naldrett AJ, Asif M (1995) Distribution of platinum-group elements in the Niquelândia layered mafic-ultramafic intrusion, Brazil: implications with respect to exploration. Can Mineral 33:165–184

    Google Scholar 

  • Garuti G, Zaccarini F, Moloshag V, Alimov V (1999) Platinum-group minerals as indicators of sulfur fugacity in ophiolitic upper mantle: an example from chromitites of the Ray-Iz ultramafic complex (Polar Urals, Russia). Can Mineral 37:1099–1116

    Google Scholar 

  • Garuti G, Meloni S, Oddone M (2000) NAA of Platinum group elements and gold in reference materials: a comparison of two methods. J Radioanal Nucl Chem 245:17–23

    Article  Google Scholar 

  • Garuti G, Pushkarev EV, Zaccarini F, Cabella R, Anikina E (2003) Chromite composition and platinum-group mineral assemblage in the Uktus Uralian-Alaskan-type complex (Central Urals, Russia). Miner Depos 38:312–326

    Google Scholar 

  • Garuti G, Pushkarev EV, Thalhammer OAR, Zaccarini F (2012) Chromitites of the urals (part 1): overview of chromite mineral chemistry and geo-tectonic setting. Ofioliti 37:27–53

    Google Scholar 

  • Hill R, Roeder PL (1974) The crystallization of spinel from basaltic liquid as a function of oxygen fugacity. J Geol 82:709–729

    Article  Google Scholar 

  • Irvine TN (1965) Chromian spinel as a petrogenetic indicator. Part I. Theory. Can J Earth Sci 2:648–672

    Article  Google Scholar 

  • Irvine TN (1967) Chromian spinel as a petrogenetic indicator. Part II. Petrological applications. Can J Earth Sci 4:71–103

    Article  Google Scholar 

  • Irvine TN (1977) Origin of chromite layers in the Muskox intrusion and other stratiform intrusions: a new interpretation. Geol 5:273–277

    Article  Google Scholar 

  • Jianping L, Kornprobst J, Vielzeuf D, Fabriès J (1995) An improved experimental calibration of the olivine-spinel geothermometer. Chin J Geochem 14:68–77

    Article  Google Scholar 

  • Johan Z, Dunlop H, Le Bel L, Robert JL, Volfinger M (1983) Origin of chromite deposits in ophiolitic complexes: evidence for a volatile and sodium-rich reducing fluid phase. Fortschr Miner 61:105–107

    Google Scholar 

  • Kamenetsky VS, Crawford AJ, Meffre S (2001) Factors controlling chemistry of magmatic spinel: an empirical study of associated olivine, Cr-spinel, and melt inclusions from primitive rocks. J Petrol 42:655–671

    Article  Google Scholar 

  • Kapsiotis A, Grammatikopoulos TA, Tsikouras B, Hatzipanagiotou K, Zaccarini F, Garuti G (2011) Mineralogy, composition and PGM of chromitites from Pefki, Pindos ophiolite complex (NW Greece): evidence for progressively elevated fAs conditions in the upper mantle sequence. Mineral Petrol 101:129–150

    Article  Google Scholar 

  • Keays RR (1995) The role of komatiitic and picritic magmatism and S saturation in the formation of ore deposits. Lithos 34:1–18

    Google Scholar 

  • Lagabrielle Y, Lemoine M (1997) Alpine, Corsican and Apennine ophiolites: the slow-spreading ridge model. C R Acad Sci (Ser IIa Sci) Terre Planétes 325:909–920

    Google Scholar 

  • Leblanc M, Nicolas A (1992) Les chromitites ophiolitiques. Chron Rech Min 507:3–25

    Google Scholar 

  • Lehmann J (1983) Diffusion between olivine and spinel: application to geothermometry. Earth Planet Sci Lett 64:123–138

    Article  Google Scholar 

  • Lemoine M, Tricart P, Boillot G (1987) Ultramafic and gabbroic ocean floor of the Ligurian Tethys (Alps, Corsica, Apennines): in search of a genetic model. Geol 15:622–625

    Article  Google Scholar 

  • Liermann HP, Ganguly J (2003) Fe2+-Mg fractionation between orthopyroxene and spinel: experimental calibration in the system FeO–MgO–Al2O3–Cr2O3–SiO2, and applications. Contrib Mineral Petrol 145:217–227

    Article  Google Scholar 

  • Liermann HP, Ganguly J (2007) Fe2+-Mg fractionation between orthopyroxene and spinel: experimental calibration in the system FeO–MgO–Al2O3–Cr2O3–SiO2, and applications. Contrib Mineral Petrol 154:491

    Article  Google Scholar 

  • MacLean WH (1969) Liquidus phase relations in the FeS-FeO-Fe3O4-SiO2 system, and their application in geology. Econ Geol 64:865–884

    Article  Google Scholar 

  • Malitch KN, Junk SA, Thalhammer OAR, Melcher F, Knauf VV, Pernicka E, Stumpfl EF (2003) Laurite and ruarsite from podiform chromitites at Kraubath and Hochgrössen, Austria: new insights from osmium isotopes. Can Mineral 41:331–352

    Article  Google Scholar 

  • Maurel C, Maurel P (1982) Etude experimentale de la distribbution de L’aluminium entre bain silicate basique et spinelle chromifere: implications petrogenetiques, teneur en chrome des spinelles. Bull Minéral 105:197–202

    Google Scholar 

  • Melcher F, Grum W, Simon G, Talhammer TV, Stumpfl EF (1997) Petrogenesis of the ophiolitic giant chromite deposits of Kempirsai, Kazakhstan: a study of solid and fluid inclusions in chromite. J Petrol 38:1419–1458

    Article  Google Scholar 

  • Melcher F, Grum W, Thalhammer TV, Thalhammer OAR (1999) The giant chromite deposits at Kempirsai, Urals: constraints from trace element (PGE, REE) and isotope data. Miner Depos 34:250–272

    Article  Google Scholar 

  • Naldrett AJ, Duke JM (1980) Platinum metals in magmatic sulphide ores. Science 208:1417–1424

    Article  Google Scholar 

  • Naldrett AJ, Lehmann J (1988) Spinel non-stoichiometry as the explanation for Ni-, Cu- and PGE-enriched sulfides in chromitites. In: Prichard HM, Potts PJ, Bowels JFW, Cribb SJ (eds) Proceedings of geo-platinum 87 symposium, Milton Keynes 1987, Elsevier, pp 93–110

  • Naldrett AJ, Von Gruenewaldt G (1989) Association of Platinum-group elements with chromitites in layered intrusions and ophiolite complexes. Econ Geol 84:180–187

    Article  Google Scholar 

  • Naldrett AJ, Kinnard JA, Wilson A, Yudovskaya M, McQuade S, Chunnett G, Stanley C (2009) Chromite composition and PGE content of Bushveld chromitites: Part I—the lower and middle groups. Trans Inst Min Metall (Sect B: Appl Earthsci) 118:131–161

    Google Scholar 

  • O’Neill HSC, Wall VJ (1987) The olivine-orthopyroxene-spinel oxygen geobarometer, the nickel precipitation curve, and the oxygen fugacity of the Earth’s upper mantle. J Petrol 28:1169–1191

    Google Scholar 

  • Peck DC, Keays RR (1990) Insights into the behaviour of precious metals in primitive S-undersaturated magmas: evidence from the Heazlewood River complex, Tasmania. Can Mineral 28:553–577

    Google Scholar 

  • Piccardo GB (2007) Evolution of the ultra-slow spreading Jurassic Ligurian Tethys: view from the mantle. Per Mineral 76:67–80

    Google Scholar 

  • Piccardo GB (2008) The Jurassic Ligurian Tethys, a fossil ultra-slow spreading ocean: the mantle perspective. In: Coltorti M, Grogoire M (eds) Metasomatism in oceanic and continental lithospheric mantle. Geol Soc London Spec Publ 294:11–33

  • Piccardo GB, Guarnieri L (2010) Alpine peridotites from the Ligurian Tethys: an updated critical review. Intern Geol Rev 52:1138–1159

    Article  Google Scholar 

  • Piccardo GB, Guarnieri L (2011) Gabbro-norite cumulates from strongly depleted MORB melts in the Alpine–Apennine ophiolites. Lithos 124:200–214

    Article  Google Scholar 

  • Piccardo GB, Rampone E, Romairone A (2002) Formation and composition of the oceanic lithosphere of the Ligurian Tethys: inferences from the Ligurian ophiolites. Ofioliti 27:145–161

    Google Scholar 

  • Rampone E, Hoffmann AW, Raczek I (1998) Isotopic contrasts within the Internal Liguride ophiolite (N. Italy): the lack of a genetic peridotite—crust link. Earth Planet Sci Lett 163:175–189

    Article  Google Scholar 

  • Renna MR, Tribuzio R (2011) Olivine-rich troctolites from Ligurian ophiolites (Italy): evidence for impregnation of replacive mantle conduits by MORB-type melts. J Petrol 52:1763–1790

    Article  Google Scholar 

  • Righter K (2001) Rhenium and iridium partitioning in silicate magmatic spinels: implications for planetary magmatism and mantles. Lun Planet Sci 32:1759

    Google Scholar 

  • Roberts S (1988) Ophiolitic chromite formation: a marginal basin phenomenon? Econ Geol 83:1034–1036

    Article  Google Scholar 

  • Robertson AHF (2002) Overview of the genesis and emplacement of Mesozoic ophiolites in the Eastern Mediterranean Tethyan region. Lithos 65:1–67

    Article  Google Scholar 

  • Roeder PL (1994) Chromite: from their fiery rain of chondrules to the Kilauea Iki lava lake. Can Mineral 32:729–746

    Google Scholar 

  • Rollinson H (2008) The geochemistry of mantle chromitites from the northern part of the Oman ophiolite: inferred parental melt compositions. Contrib Mineral Petrol 156:273–288

    Article  Google Scholar 

  • Stella A (1924) Sopra un giacimento di cromite nel Vallone Argentiera presso Ziona (Alta Valle Vara). Boll Soc Geol It 43:183–188

    Google Scholar 

  • Stowe CW (1994) Compositions and tectonic settings of chromite deposits through time. Econ Geol 89:528–546

    Article  Google Scholar 

  • Thayer TP (1970) Chromite segregations as petrogenetic indicators. Geol Soc S Afr Spec Publ 1:380–390

    Google Scholar 

  • Tribuzio R, Thirlwall MF, Vannucci R (2004) Origin of the Gabbro-Peridotite association from the Northern Apennine Ophiolites (Italy). J Petrol 45:1109–1124

    Article  Google Scholar 

  • Von Gruenewaldt G, Merkle RKW (1995) Platinum group element proportions in chromitites of the Bushveld complex: implications for fractionation and magma mixing models. J Afr Earth Sci 21:615–632

    Article  Google Scholar 

  • Zaccarini F, Proenza JA (2005) Zirconolite from upper mantle chromitite: a key to understanding mantle metasomatic processes. Actas XVI Congr Geol Argentino 2005:346

    Google Scholar 

  • Zaccarini F, Garuti G, Proenza JA, Campos L, Thalhammer OAR, Aiglsperger T, Lewis J (2011) Chromite and platinum-group-elements mineralization in the Santa Elena ophiolitic ultramafic nappe (Costa Rica): geodynamic implications. Geol Acta 9:407–423

    Google Scholar 

  • Zhou MF, Robinson PT (1994) High-Cr and high-Al podiform chromitites, Western China: relationship to partial melting and melt/rock reaction in the upper mantle. Intern Geol Rev 36:678–686

    Article  Google Scholar 

  • Zhou MF, Robinson PT, Bai WJ (1994) Formation of podiform chromitites by melt/rock interaction in the upper mantle. Miner Dep 29:98–101

    Google Scholar 

  • Zhou MF, Sun M, Keays RR, Kerrich RW (1998) Controls on platinum-group elemental distributions of podiform chromitites: a case study of high-Cr and high-Al chromitites from Chinese orogenic belts. Geochim Cosmochim Acta 62:677–688

    Article  Google Scholar 

Download references

Acknowledgments

We thank the University Centrum for Applied Geosciences (UCAG) for the access to the E. F. Stumpfl electron microprobe laboratory and H. Mühlhans for the sample preparation. Many thanks are due to S. Arai and R. Tribuzio for their comments and to T.L. Grove for his editorial handling.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to R. J. Baumgartner.

Additional information

Communicated by T. L. Grove.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Baumgartner, R.J., Zaccarini, F., Garuti, G. et al. Mineralogical and geochemical investigation of layered chromitites from the Bracco–Gabbro complex, Ligurian ophiolite, Italy. Contrib Mineral Petrol 165, 477–493 (2013). https://doi.org/10.1007/s00410-012-0818-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00410-012-0818-5

Keywords

Navigation