Access the full text.
Sign up today, get DeepDyve free for 14 days.
W. Maier, B. Karykowski, Shengli Yang (2016)
Formation of transgressive anorthosite seams in the Bushveld Complex via tectonically induced mobilisation of plagioclase-rich crystal mushesGeoscience frontiers, 7
D. Jerram, M. Cheadle, A. Philpotts (2003)
Quantifying the Building Blocks of Igneous Rocks: Are Clustered Crystal Frameworks the Foundation?Journal of Petrology, 44
E. Cameron (1978)
An unusual titanium-rich oxide mineral from the eastern Bushveld ComplexAmerican Mineralogist, 63
L. Ashwal, S. Webb, M. Knoper (2005)
Magmatic stratigraphy in the Bushveld Northern Lobe: continuous geophysical and mineralogical data from the 2950 m Bellevue drillcoreSouth African Journal of Geology, 108
C. Lee, M. Tredoux (1986)
Platinum-group element abundances in the lower and the lower critical zones of the eastern Bushveld ComplexEconomic Geology, 81
S. Boorman, A. Boudreau, F. Kruger (2004)
The Lower Zone–Critical Zone Transition of the Bushveld Complex: a Quantitative Textural StudyJournal of Petrology, 45
J. Lorand, J. Cottin, G. Parodi (1987)
OCCURRENCE AND PETROLOGICAL SIGNIFICANCE OF LOVERINGITE IN THE WESTERN LAOUNI LAYERED COMPLEX, SOUTHERN HOGGAR, ALGERIACanadian Mineralogist, 25
D. Nicholson, E. Mathez (1991)
Petrogenesis of the Merensky Reef in the Rustenburg section of the Bushveld ComplexContributions to Mineralogy and Petrology, 107
J. Scoates, C. Wall (2015)
Geochronology of Layered Intrusions
B. Godel, S. Barnes, W. Maier (2011)
Parental magma composition inferred from trace element in cumulus and intercumulus silicate minerals: An example from the Lower and Lower Critical Zones of the Bushveld Complex, South-AfricaLithos, 125
A. Boudreau (1999)
PELE—a version of the MELTS software program for the PC platformComputers & Geosciences, 25
J. Mungall, S. Kamo, S. McQuade (2016)
U–Pb geochronology documents out-of-sequence emplacement of ultramafic layers in the Bushveld Igneous Complex of South AfricaNature Communications, 7
R. Scoon, B. Teigler (1995)
A new LG-6 chromite reserve at Eerste Geluk in the boundary zone between the central and southern sectors of the eastern Bushveld ComplexEconomic Geology, 90
E. Mathez, T. Waight (2003)
Lead isotopic disequilibrium between sulfide and plagioclase in the bushveld complex and the chemical evolution of large layered intrusionsGeochimica et Cosmochimica Acta, 67
W. Maier, N. Arndt, Edward Curl (2000)
Progressive crustal contamination of the Bushveld Complex: evidence from Nd isotopic analyses of the cumulate rocksContributions to Mineralogy and Petrology, 140
H. Eales, W. Klerk, B. Teigler (1990)
Evidence for magma mixing processes within the Critical and Lower Zones of the northwestern Bushveld Complex, South AfricaChemical Geology, 88
I. McDonald, D. Holwell (2011)
Geology of the Northern Bushveld Complex and the Setting andGenesis of the Platreef Ni-Cu-PGE Deposit
JD Webster, PM Piccoli (2015)
Magmatic apatite: a powerful, yet deceptiveMineral Elem, 11
E. Cameron (1979)
Titanium-bearing oxide minerals of the Critical Zone of the Eastern Bushveld ComplexAmerican Mineralogist, 64
J. Engelbrecht (1985)
The chromites of the Bushveld Complex in the Nietverdiend areaEconomic Geology, 80
Mpho Mangwegape, F. Roelofse, T. Mock, R. Carlson (2016)
The Sr-isotopic stratigraphy of the Northern Limb of the Bushveld Complex, South AfricaJournal of African Earth Sciences, 113
C. Wall (2016)
Establishing the age and duration of magmatism in large open-system layered intrusions from the high-precision geochronology of the Neoarchean Stillwater Complex and Paleoproterozoic Bushveld Complex
W. Meurer, M. Meurer (2006)
Using apatite to dispel the “trapped liquid” concept and to understand the loss of interstitial liquid by compaction in mafic cumulates: an example from the Stillwater Complex, MontanaContributions to Mineralogy and Petrology, 151
Allan Wilson (2012)
A Chill Sequence to the Bushveld Complex: Insight into the First Stage of Emplacement and Implications for the Parental MagmasJournal of Petrology, 53
W. Maier, S. Barnes, D. Groves (2012)
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 chamberMineralium Deposita, 48
(1994)
Loveringite: a first occurrence in Russia from the Burakovsky layered intrusion
M. Yudovskaya, J. Kinnaird, A. Sobolev, D. Kuzmin, I. McDonald, Allan Wilson (2013)
Petrogenesis of the Lower Zone Olivine-Rich Cumulates Beneath the Platreef and Their Correlation with Recognized Occurrences in the Bushveld ComplexEconomic Geology, 108
Shenghong Yang, W. Maier, Y. Lahaye, H. O’Brien (2013)
Strontium isotope disequilibrium of plagioclase in the Upper Critical Zone of the Bushveld Complex: evidence for mixing of crystal slurriesContributions to Mineralogy and Petrology, 166
C. Seabrook, R. Cawthorn, F. Kruger (2005)
The Merensky Reef, Bushveld Complex: Mixing of Minerals Not Mixing of MagmasEconomic Geology, 100
W. Meurer, A. Boudreau (1996)
Compaction of Density-Stratified Cumulates: Effect on Trapped-Liquid DistributionThe Journal of Geology, 104
W. Maier, L. Klerk, J. Blaine, T. Manyeruke, S. Barnes, M.V.A. Stevens, John Mavrogenes (2008)
Petrogenesis of contact-style PGE mineralization in the northern lobe of the Bushveld Complex: comparison of data from the farms Rooipoort, Townlands, Drenthe and NonnenwerthMineralium Deposita, 43
Τ. Irvine (1980)
Chapter 8. Magmatic Infiltration Metasomatism, Double-Diffusive Fractional Crystallization, and Adcumulus Growth in the Muskox Intrusion and other Layered Intrusions
B. Mason (1966)
Composition of the EarthNature, 211
H. Naslund, A. Mcbirney (1996)
Mechanisms of Formation of Igneous LayeringDevelopments in Petrology, 15
J. Bédard, R. Kerr, Mark Hallworth (1992)
Porous sidewall and sloping floor crystallization experiments using a reactive mush: Implications for the self-channelization of residual melts in cumulatesEarth and Planetary Science Letters, 111
E. Mathez, A. Kent (2007)
Variable initial Pb isotopic compositions of rocks associated with the UG2 chromitite, eastern Bushveld ComplexGeochimica et Cosmochimica Acta, 71
Teigler Eb (2016)
Mineralogy, petrology and geochemistry of the lower and lower critical zones, northwestern Bushveld Complex
L. Wager (1960)
The Major Element Variation of the Layered Series of the Skaergaard Intrusion and a Re-estimation of the Average Composition of the Hidden Layered Series and of the Successive Residual MagmasJournal of Petrology, 1
S. Barnes (1986)
The effect of trapped liquid crystallization on cumulus mineral compositions in layered intrusionsContributions to Mineralogy and Petrology, 93
Allan Wilson (2015)
The Earliest Stages of Emplacement of the Eastern Bushveld Complex: Development of the Lower Zone, Marginal Zone and Basal Ultramafic SequenceJournal of Petrology, 56
F. Roelofse, L. Ashwal (2012)
The Lower Main Zone in the Northern Limb of the Bushveld Complex—a >1·3 km Thick Sequence of Intruded and Variably Contaminated Crystal MushesJournal of Petrology, 53
AL Hall (1932)
The Bushveld Igneous Complex of the central TransvaalMem Geol Surv S Afr, 28
P. Piccoli, P. Candela (2002)
Apatite in Igneous SystemsReviews in Mineralogy & Geochemistry, 48
E. Cameron (1978)
The Lower Zone of the Eastern Bushveld Complex in the Olifants River TroughJournal of Petrology, 19
(1982)
The geology, geochemistry and silicate mineralogy of the Upper Critical Zone of the North-western Bushveld Complex, at Rustenburg Platinum Mines, Union section
HV Eales, RG Cawthorn (1996)
Developments in petrology
J. Webster, P. Piccoli (2015)
Magmatic Apatite: A Powerful, Yet Deceptive, MineralElements, 11
N. Chutas, E. Bates, S. Prevec, Drew Coleman, A. Boudreau (2012)
Sr and Pb isotopic disequilibrium between coexisting plagioclase and orthopyroxene in the Bushveld Complex, South Africa: microdrilling and progressive leaching evidence for sub-liquidus contamination within a crystal mushContributions to Mineralogy and Petrology, 163
H. Carr, D. Groves (1994)
The importance of synmagmatic deformation in the formation of Merensky Reef potholes in the Bushveld ComplexEconomic Geology, 89
M. Sharpe (1981)
The chronology of magma influxes to the eastern compartment of the Bushveld Complex as exemplified by its marginal border groupsJournal of the Geological Society, 138
B. Karykowski, P. Polito, W. Maier, J. Gutzmer, J. Krause (2017)
New insights into the petrogenesis of the Jameson Range layered intrusion and associated Fe-Ti-P-V-PGE-Au mineralisation, West Musgrave Province, Western AustraliaMineralium Deposita, 52
M. Tarkian, T. Mutanen (1987)
Loveringite from the koitelainen layered intrusion, Northern FinlandMineralogy and Petrology, 37
A. Zeh, M. Ovtcharova, Allan Wilson, U. Schaltegger (2015)
The Bushveld Complex was emplaced and cooled in less than one million years – results of zirconology, and geotectonic implicationsEarth and Planetary Science Letters, 418
TN Irvine (1980)
Physics of magmatic processes
T. Alapieti, J. Lahtinen (1986)
Stratigraphy, petrology, and platinum-group element mineralization of the early Proterozoic Penikat layered intrusion, northern FinlandEconomic Geology, 81
B. Gatehouse, I. Grey, I. Campbell, P. Kelly (1978)
The crystal structure of loveringite, a new member of the crichtonite groupAmerican Mineralogist, 63
S. Barnes, W. Maier, Edward Curl (2010)
Composition of the marginal rocks and sills of the Rustenburg Layered Suite, Bushveld Complex, South Africa: Implications for the formation of the Platinum-group element depositsEconomic Geology, 105
H. Eales, R. Cawthorn (1996)
The Bushveld ComplexDevelopments in Petrology, 15
Page 17 of 18 60 cumulate slurry in a large, relatively slowly cooling, subsiding magma chamber
W. Maier, S. Barnes, B. Karykowski (2016)
A chilled margin of komatiite and Mg-rich basaltic andesite in the western Bushveld Complex, South AfricaContributions to Mineralogy and Petrology, 171
C. Tegner, R. Cawthorn, F. Kruger (2006)
Cyclicity in the Main and Upper Zones of the Bushveld Complex, South Africa: Crystallization from a Zoned Magma SheetJournal of Petrology, 47
JS Scoates, CJ Wall (2015)
Layered intrusions
L. Hulbert (1983)
A Petrological investigation of the Rustenburg layered suite and associated mineralization South of Potgietersrus
R. Cawthorn (2015)
The Bushveld Complex, South Africa
S. Tait, C. Jaupart (1992)
Compositional convection in a reactive crystalline mush and melt differentiationJournal of Geophysical Research, 97
A. Yu, E. Savchenko, L. Barkova (1996)
Loveringite from the Last-Yavr mafic-ultramafic intrusion, Kola Peninsula; a second occurrence in Russia
N. Tollari, D. Baker, S. Barnes (2008)
Experimental effects of pressure and fluorine on apatite saturation in mafic magmas, with reference to layered intrusions and massif anorthositesContributions to Mineralogy and Petrology, 156
S. Prevec, S. Prevec, L. Ashwal, M. Mkaza (2005)
Mineral disequilibrium in the Merensky Reef, western Bushveld Complex, South Africa: new Sm–Nd isotopic evidenceContributions to Mineralogy and Petrology, 149
The Lower Zone of the Bushveld Complex comprises an up to 2-km-thick package of different ultramafic rock types with an approx. 90-cm-thick, sulphide-bearing noritic interval that occurs in the western and eastern limbs. The distribution and geometry of the zone are highly variable across the Complex, showing pronounced, yet laterally discontinuous layering on different scales. Together with the ubiquitous lack of large-scale fractionation in the Mg# of orthopyroxene, variable Sr isotope compositions and erratic Pt/Pd ratios, these observations strongly suggest an emplacement of the Lower Zone as a sill complex, as these contrasting geochemical characteristics are difficult to account for in a large Bushveld magma chamber, as previously suggested. It is more likely that these sills were episodically fed from a sub-Bushveld staging chamber, and variably contaminated, while passing through the crust before their final emplacement in the Lower Zone. Detailed mineralogical and microtextural work based on high-resolution elemental mapping of a set of samples, covering the entire Lower Zone stratigraphy of the western Bushveld shows that the variations in the late crystallising interstitial mineral mode are different from what would be expect, if all phases crystallised from a fixed initial mass of interstitial liquid. The interstitial mineral mode, represented by plagioclase, clinopyroxene and other late stage phases, shows variable ratios of these minerals ranging from ca. 21:15:64 to 75:17:8. In comparison to modelled expected ratios, most of the analysed rocks have higher amounts of early crystallising interstitial phases (e.g. plagioclase, clinopyroxene), relative to late crystallising phases (e.g. quartz, alkali feldspar). Therefore, interstitial melt must have migrated at different stages of fractionation during cumulate solidification, as a consequence of either compaction or displacement by convecting interstitial liquids. Two samples, however, show the opposite: late phases are relatively more abundant than early ones, which is consistent with a convection-driven replacement of primitive interstitial liquid by more evolved liquid. These results have important implications for the interpretation of the Lower Zone and, by extension, for layered intrusions in general: (1) interstitial sulphide mineralisation may be introduced into a cumulate through infiltrating melts, i.e. the liquid components of a sulphur-saturated crystal mush are not withheld from further migration, upon interaction with a cumulate pile; (2) most importantly, late stage minerals, such as zircon, rarely crystallise from trapped liquid that was initially in equilibrium with the cumulate. Therefore, dating of interstitial zircon from cumulates is unlikely to record the actual timing of emplacement, but merely the crystallisation of a later episode of residual melt that migrated through the cumulate.
Contributions to Mineralogy and Petrology – Springer Journals
Published: Jul 7, 2017
Read and print from thousands of top scholarly journals.
Already have an account? Log in
Bookmark this article. You can see your Bookmarks on your DeepDyve Library.
To save an article, log in first, or sign up for a DeepDyve account if you don’t already have one.
Copy and paste the desired citation format or use the link below to download a file formatted for EndNote
Access the full text.
Sign up today, get DeepDyve free for 14 days.
All DeepDyve websites use cookies to improve your online experience. They were placed on your computer when you launched this website. You can change your cookie settings through your browser.