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Geothermometry of garnet lherzolite nodules with special reference to those from the kimberlites of Northern Lesotho

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Abstract

Different published geothermometric methods have been tested on a large suite of garnet lherzolite nodules from the kimberlites of Northern Lesotho. Comparison of the various calculated equilibration temperature estimates indicates that several of these methods yield unreliable results and should therefore be rejected. However, there is little to choose between the values obtained from five other methods based on three different element exchange reactions. Accordingly we conclude that the petrogenesis of garnet lherzolite nodules is best discussed with reference to the mean temperature estimates derived from these five preferred methods. The late Cretaceous palaeogeotherm for Northern Lesotho is revised on this basis and found to be of a similar form to previous estimates but is significantly displaced to higher temperatures.

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Authors and Affiliations

  1. Department of Geology, University of Sheffield, Mappin Street, S1 3JD, Sheffield, UK

    D. A. Carswell & F. G. F. Gibb

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  1. D. A. Carswell
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  2. F. G. F. Gibb
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Carswell, D.A., Gibb, F.G.F. Geothermometry of garnet lherzolite nodules with special reference to those from the kimberlites of Northern Lesotho. Contr. Mineral. and Petrol. 74, 403–416 (1980). https://doi.org/10.1007/BF00518120

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  • DOI: https://doi.org/10.1007/BF00518120

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