Skip to main content

Advertisement

SpringerLink
Log in

Idiomorphic oikocrysts of clinopyroxene produced by a peritectic reaction within a solidification front of the Bushveld Complex

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

Abstract

Orthopyroxenite cumulates throughout the Critical Zone of the Bushveld Complex commonly contain prominent euhedral crystals of bottle-green augite, typically around 1 cm in size and surrounded by “haloes” of nearly pure plagioclase. On close examination, the augite grains can be seen to be oikocrysts, containing extensively resorbed chadacrysts of orthopyroxene, indicating an effective peritectic reaction relationship between the two pyroxenes. A detailed textural study of one such layer from the UG3 Unit in the Eastern Bushveld reveals some distinctive grain-scale features, including the presence of extensively 3D-interconnected chains of thousands of cumulus chromite grains that surround the orthopyroxene grains and extend through the augite oikocrysts. The high degree of interconnectivity is remarkable in view of the relatively low (5 vol.%) modal proportion of chromite in the sample. Other noteworthy features include zoning of the oikocrysts towards higher incompatible element contents in the rims and the presence of the plagioclase haloes around the augite oikocrysts. These haloes are essentially narrow zones devoid of orthopyroxene inclusions developed within large plagioclase oikocrysts that overgrow all the other phases. We propose a mechanism whereby the plagioclase oikocrysts grow early in communication with the main magma body within an initial crystal mush of orthopyroxene and chain-textured chromite. The clinopyroxene oikocrysts grew in the remaining pore space in such a way that dissolution of orthopyroxene occurred within a narrow few-mm wide chemical boundary layer ahead of the advancing oikocryst margin. The relative rates of crystallisation and dissolution were controlled by limited chemical diffusion through the boundary layer such that orthopyroxene grains more than a few grain diameters away showed no reaction at all. The plagioclase haloes developed as a result of continuing growth of the plagioclase oikocrysts to overtake the growing pyroxene oikocrysts, locking in the orthopyroxene-depleted boundary layer, and preserving euhedral cumulus morphologies away from the pyroxene oikocrysts. This texture represents a circumstance whereby oikocrysts in the same rock develop at different overlapping stages: plagioclase oikocrysts forming early in diffusive connection with the magma column, and clinopyroxene forming peritectic poikilitic textures within residual liquid pockets chemically isolated from the overlying magma body.

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

Fig. 1 
Fig. 2 
Fig. 3 
Fig. 4 
Fig. 5 
Fig. 6 
Fig. 7 
Fig. 8 
Fig. 9 
Fig. 10 
Fig. 11 
Fig. 12 
Fig. 13 
Fig. 14 

Similar content being viewed by others

References

  • Ashwal LD (1993) Anorthosites. Minerals Rocks 21:422. https://doi.org/10.1007/978-3-642-77440-9

    Article  Google Scholar 

  • Barnes SJ (1986) The effect of trapped liquid crystallization on cumulus mineral compositions in layered intrusions. Contrib Mineral Petrol 93:524–531

    Article  Google Scholar 

  • Barnes SJ, Jones S (2012) Deformed chromitite layers in the Coobina intrusion, Pilbara Craton, Western Australia. Econ Geol 108:337–354. https://doi.org/10.2113/econgeo.108.2.337

    Article  Google Scholar 

  • Barnes SJ, Le Vaillant M, Godel B, Lesher CM (2019) Droplets and bubbles: solidification of sulphide-rich vapour-saturated orthocumulates in the Noril’sk-Talnakh Ni-Cu-PGE ore-bearing intrusions. J Petrol 60:269–300. https://doi.org/10.1093/petrology/egy114

    Article  Google Scholar 

  • Barnes SJ, Mole DR, Le Vaillant M, Campbell M, Verrall M, Roberts M, Evans NJ (2016) Poikilitic textures, heteradcumulates and zoned orthopyroxenes in the Ntaka Ultramafic Complex, Tanzania: implications for crystallisation mechanisms of oikocrysts. J Petrol 57:1171–1198. https://doi.org/10.1093/petrology/egw036

    Article  Google Scholar 

  • Barnes SJ, Robertson JC (2019) Time scales and length scales in magma flow pathways and the origin of magmatic Ni-Cu-PGE ore deposits. Geosci Front 10:77–87. https://doi.org/10.1016/j.gsf.2018.02.006

    Article  Google Scholar 

  • Boorman S, Boudreau AE, Kruger FJ (2004) The lower Zone-critical zone transition of the Bushveld Complex: a quantitative textural study. J Petrol 45(6):1209–1235. https://doi.org/10.1093/petrology/egh011

    Article  Google Scholar 

  • Campbell IH (1968) The origin of heteradcumulate and adcumulate textures in the JimberlanaNorite. Geol Mag 105:378–383

    Article  Google Scholar 

  • Campbell IH (1978) Some problems with the cumulus theory. Lithos 11:311–323

    Article  Google Scholar 

  • Cawthorn RG (1976) Calcium-poor pyroxene reaction relations in calc-alkaline magmas. Am Miner 61(9–10):907–912

    Google Scholar 

  • Cherniak DJ, Dimanov A, Zhang Y, Cherniak D (2010) Diffusion in pyroxene, mica and amphibole. Rev Mineral Geochem 72:641–690. https://doi.org/10.2138/rmg.2010.72.14

    Article  Google Scholar 

  • Coertze FJ (1958) Intrusive relationships and ore-deposits in the western part of the Bushveld igneous complex. Verhandelinge van die Geologiese Vereniging van Suid Afrika = Transactions of the Geological Society of South Africa 61:387–400

  • Eales HV, Reynolds IM (1986) Cryptic variations within chromitites of the Upper Critical Zone, Northwestern Bushveld Complex. Econ Geol 81:1056–1066

    Article  Google Scholar 

  • Forien M, Tremblay J, Barnes S-J, Pagé P (2015) The role of viscous particle segregation in forming chromite layers from slumped crystal slurries; insights from analogue experiments. J Petrol 56:2425–2444

    Article  Google Scholar 

  • Godel B, Barnes SJ, Gurer D, Austin P, Fiorentini ML (2013) Chromite in komatiites: 3D morphologies with implications for crystallization mechanisms. Contrib Mineral Petrol 165:173–189. https://doi.org/10.1007/s00410-012-0804-y

    Article  Google Scholar 

  • Higgins MD (1998) Origin of anorthosite by textural coarsening; quantitative measurements of a natural sequence of textural development. J Petrol 39(7):1307–1323. https://doi.org/10.1093/petrology/39.7.1307

    Article  Google Scholar 

  • Holness MB, Cawthorn RG, Roberts J (2017) The thickness of the crystal mush on the floor of the Bushveld magma chamber. Contrib Mineral Petrol 172(11–12):102–102

    Article  Google Scholar 

  • Holness MB, Vukmanovic Z, Mariani E (2017) Assessing the role of compaction in the formation of adcumulates; a microstructural perspective. J Petrol 58(4):643–674. https://doi.org/10.1093/petrology/egx037

    Article  Google Scholar 

  • Irvine TN (1970) Crystallization sequences in the Muskox Intrusion and other layered intrusions I. Olivine-pyroxene-plagioclase relations. In: Visser DJL, Von Gruenewaldt G (eds), vol., pp 441–476.

  • Irvine TN (1980) Magmatic density currents and cumulus processes. Amer J Sci 280A:1–58

    Google Scholar 

  • Jackson ED (1961) Primary textures and mineral associations in the Ultramafic zone of the Stillwater Complex, Montana. U S GeolSurv Prof Paper 358:1–106

    Google Scholar 

  • Jackson ED (1970) The cyclic units in layered intrusions - a comparison of repetitive stratigraphy in the ultramafic parts of the Stillwater, Muskox, Great Dyke and Bushveld Complexes. In: Visser DJL, Von Gruenewaldt G (eds), vol., pp 391–424.

  • Jenkins MC, Mungall JE (2018) Genesis of the Peridotite Zone, Stillwater Complex, Montana, USA. J Petrol 59:2157–2190

    Article  Google Scholar 

  • Kaufmann FED, Vukmanovic Z, Holness MB, Hecht L (2018) Orthopyroxene oikocrysts in the MG1chromitite layer of the Bushveld Complex: implications for cumulate formation and recrystallisation. Contrib Mineral Petrol 173:17. https://doi.org/10.1007/s00410-018-1441-x

    Article  Google Scholar 

  • Kerr RC, Tait SR (1985) Convective exchange between pore fluid and an overling reservoir of dense fluid: a postcumulus process in layered intrusions. Earth Planet Sci Letts 75:147–156

    Article  Google Scholar 

  • Kerr RC, Tait SR (1986) Crystallisation and compositional convection in a porous medium with application to layered igneous intrusions. J Geophys Res 91:3591–3608

    Article  Google Scholar 

  • Kirkham R, Dunn P, Kuczewski A, Siddons D, Dodanwela R, Moorhead G, Ryan C, De Geronimo G, Beuttenmuller R, Pinelli D, Pfeffer M, Davey P, Jensen M, Paterson D, de Jonge M, Kusel M, McKinlay J (2010) The Maia spectroscopy detector system: engineering for integrated pulse capture, low-latency scanning and real-time processing. Proc Aust Inst Phys 1234:240–243

    Google Scholar 

  • Kushiro I (1972) Determination of liquidus relations in synthetic silicate systems with electron probe analysis; the system forsterite–diopside–silica at 1 atmosphere. Am Miner 57(7–8):1260–1271

    Google Scholar 

  • Latypov R, Chistyakova S, Barnes SJ, Hunt EJ (2017) Origin of platinum deposits in layered intrusions by in situ crystallization: evidence from undercutting Merensky Reef of the Bushveld Complex. J Petrol 58:715–761. https://doi.org/10.1093/petrology/egx032

    Article  Google Scholar 

  • Latypov R, Chistyakova S, Page A, Hornsey R (2015) Field evidence for the in situ crystallization of the Merensky Reef. J Petrol 56(12):2341–2372

    Article  Google Scholar 

  • Latypov R, Morse A, Robins B, Wilson R, Cawthorn G, Tegner C, Holness M, Lesher C, Barnes S, O’Driscoll B, Veksler I, Higgins M, Wilson A, Namur O, Chistyakova S, Naslund R, Thy P (2015) A fundamental dispute: a discussion of “on some fundamentals of igneous petrology” by Bruce D.Marsh. Contrib Mineral Petrol 166:665–690. https://doi.org/10.1007/s00410-015-1108-9

    Article  Google Scholar 

  • Latypov RM, Chistyakova SY (2020a) Origin of non-cotectic cumulates: a novel approach. Geology 48(6):604–608. https://doi.org/10.1130/G47082.1

    Article  Google Scholar 

  • Latypov RM, Chistyakova SY (2020b) Origin of non-cotectic cumulates; a novel approach. Geology 48(6):604–608. https://doi.org/10.1130/G47082.1

    Article  Google Scholar 

  • Latypov RM, Chistyakova SY, Mukherjee R (2017) A novel hypothesis for origin of massive chromitites in the Bushveld Igneous Complex. J Petrol 58:1899–1940

    Article  Google Scholar 

  • Latypov RM, Chistyakova SY, Namur O, Barnes SJ (2020) Dynamics of evolving basaltic magma chambers: textural and chemical evolution of cumulates at the arrival of new liquidus phases. Earth Sci Rev Rev 4:103388

    Article  Google Scholar 

  • Maier WD, Barnes S-J, Groves DI (2013) The Bushveld Complex, South Africa; formation of platinum-palladium, chrome- and vanadium-rich layers via hydrodynamic sorting of a mobilized cumulate slurry in a large, relatively slowly cooling, subsiding magma chamber. Mineral Depos 48(1):1–56. https://doi.org/10.1007/s00126-012-0436-1

    Article  Google Scholar 

  • Manoochehri S, Schmidt MW, Britz W (2015) Trapped liquid, paleo-porosity and formation time scale of chromitite-(ortho)pyroxenite cumulate section, Bushveld. South Africa J Petrol 56(11):2195–2222. https://doi.org/10.1093/petrology/egv069

    Article  Google Scholar 

  • Mao YJ, Barnes SJ, Duan J, Qin KZ, Godel B, Jiao JG (2018) Morphology and particle size distribution of olivines and sulphides in the Jinchuan Ni-Cu sulphide deposit: Evidence for sulphide percolation in a crystal mush. J Petrol in press. https://doi.org/10.1093/petrology/egy077

    Article  Google Scholar 

  • Mathison CI (1987) Pyroxene oikocrysts in troctolitic cumulates; evidence for supercooled crystallisation and postcumulus modification. Contrib Mineral Petrol 97(2):228

    Article  Google Scholar 

  • McBirney AR, Noyes RM (1979) Crystallization and layering in the Skaergaard Intrusion. J Petrol 20:487–554

    Article  Google Scholar 

  • Miyazaki K (2015) Diffusion-controlled growth and degree of disequilibrium of garnet porphyroblasts: is diffusion-controlled growth of porphyroblasts common? Prog Earth Planet Sci 2:25. https://doi.org/10.1186/s40645-015-0055-4

    Article  Google Scholar 

  • Morse SA (1986) Convection in aid of adcumulus growth. J Petrol 27:1183–1214

    Article  Google Scholar 

  • Mungall JE (2002) Kinetic controls on the partitioning of trace elements between silicate and sulfide liquids. J Petrol 43:749–768

    Article  Google Scholar 

  • Paton C, Hellstrom J, Paul B, Woodhead J, Hergt J (2011) Iolite: freeware for the visualisation and processing of mass spectrometric data. J Anal Atomic Spectrometry 26:2508–2518. https://doi.org/10.1039/c1ja10172b

    Article  Google Scholar 

  • Ryan C, Kirkham R, Moorhead G, Parry D, Jensen M, Faulks A, Hogan S, Dunn P, Dodanwela R, Fisher L, Pearce M, Siddons D, Kuczewski A, Lundström U, Trolliet A, Gao N (2018) Maia Mapper: high definition XRF imaging in the lab. J Instrum 13:C03020. https://doi.org/10.1088/1748-0221/13/03/C03020

    Article  Google Scholar 

  • Ryan CG, Siddons DP, Kirkham R et al (2014) Maia X-ray fluorescence imaging: capturing detail in complex natural samples. J Phys Conf Ser 499(1):012002. https://doi.org/10.1088/1742-6596/499/1/012002

    Article  Google Scholar 

  • Schoneveld LE, Barnes SJ, Makkonen HV, Le Vaillant M, Paterson DJ, Taranovic V, Wang K-Y, Mao Y-J (2020) Zoned Pyroxenes as prospectivity indicators for magmatic Ni-Cu sulfide mineralization. Front Earth Sci 8:256. https://doi.org/10.3389/feart.2020.00256

    Article  Google Scholar 

  • Sparks RSJ, Kerr RC, McKenzie DP, Tait SR (1985) Postcumulus processes in layered intrusions. Geol Mag 122:555–568

    Article  Google Scholar 

  • Ubide T, McKenna CA, Chew DM, Kamber BS (2015) High-resolution LA-ICP-MS trace element mapping of igneous minerals; in search of magma histories. Chem Geol 409:157–168. https://doi.org/10.1016/j.chemgeo.2015.05.020

    Article  Google Scholar 

  • von Gruenewaldt G (1979) A review of some recent concepts of the Bushveld Complex, with particular reference to sulfide mineralization. Can Mineral 17(2):233–256

    Google Scholar 

  • Wager LR, Brown GM (1968) Layered igneous rocks. In, vol. Oliver and Boyd, Edinburgh and London, p 588 pp

  • Wager LR, Brown GM, Wadsworth WJ (1960) Types of igneous cumulates. J Petrol 1(7):73–85

    Article  Google Scholar 

  • Waters C, Boudreau AE (1996) A reevaluation of crystal-size distributions in chromite cumulates. Amer Mineral 81:1452–1459

    Article  Google Scholar 

  • Wieser PE, Vukmanovic Z, Kilian R, Ringe E, Holness MB, Maclennan J, Edmonds M (2019) To sink, swim, twin, or nucleate; a critical appraisal of crystal aggregation processes. Geology (Boulder) 47(10):948–952. https://doi.org/10.1130/G46660.1

    Article  Google Scholar 

Download references

Acknowledgements

A portion of this research was conducted at the XFM beamline at the Australian Synchrotron, operated by ANSTO. We thank David Paterson for assistance. We thank Gareth Moorhead and Chris Ryan for assistance with the Maia Mapper XFM work, carried out at the CSIRO Clayton laboratory. The laser ablation data was collected in the National Geosequestration Laboratory (NGL) at CSIRO, Perth. The study was supported by research grants to Rais Latypov and Sofya Chistyakova from the National Research foundation (NRF) and Department of Science and Technology (DST)–NRF Centre of Excellence for Integrated Mineral and Energy Resource Analysis (CIMERA) of South Africa. Any opinion, finding, and conclusion expressed in this contribution is that of the authors, and the NRF and DST-NRF CIMERA do not accept any liability in this regard. We thank Brian O’Driscoll and Margaux Le Vaillant for helpful reviews of a preliminary draft and Alan Boudreau and Michael Higgins for constructive peer-reviews that substantially improved the paper.

Author information

Authors and Affiliations

  1. CSIRO Mineral Resources, Kensington, Pert, Australia

    Stephen J. Barnes, Bélinda Godel & Louise E. Schoneveld

  2. School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa

    Rais Latypov & Sofya Chistyakova

Authors
  1. Stephen J. Barnes
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Rais Latypov
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Sofya Chistyakova
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Bélinda Godel
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Louise E. Schoneveld
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Stephen J. Barnes.

Additional information

Communicated by Steven Reddy.

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Barnes, S.J., Latypov, R., Chistyakova, S. et al. Idiomorphic oikocrysts of clinopyroxene produced by a peritectic reaction within a solidification front of the Bushveld Complex. Contrib Mineral Petrol 176, 5 (2021). https://doi.org/10.1007/s00410-020-01747-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s00410-020-01747-4

Keywords

Search

Navigation