Abstract
The chemical compositions of garnets from a megacryst association of the Mir kimberlite pipe have been studied. By petrogenic elements, the garnet megacrysts can be classified as high-Ti and low-Cr pyrope. The megacryst TiO2 contents of the Mir pipe correlate inversely with the MgO and Cr2O3 contents. Modeling of the composition of garnets through a fractional crystallization process showed that the most suitable composition of the melts parental for the garnets of the megacryst association is picrite. The composition of garnets crystallized from the kimberlite does not correspond to the composition of the natural garnets from the Mir pipe. The kimberlites contain less Ti, Zr, Y, and HREEs, but are more enriched with strongly incompatible elements (LREEs, Th, U, Nb, Ta, and Ba) than the model composition of the melt suitable for crystallization of the garnet megacrysts.
Similar content being viewed by others
REFERENCES
A. Moore and E. Belousova, Contrib. Mineral. Petrol. 149, 462–481 (2005).
R. A. Jones, in Mantle Xenoliths (John Wiley and Sons, Chichester, 1987), pp. 711–724.
G. R. Davies, A. J. Spriggs, and P. J. Nixon, J. Petrol. 42, 159–172 (2001).
A. M. Agashev, D. A. Ionov, N. P. Pokhilenko, A. V. Golovin, Yu. Cherepanova, and I. S. Sharygin, Lithos 160, 201–215 (2013).
A. M. Agashev, N. P. Pokhilenko, V. G. Mal’kovets, and N. V. Sobolev, Dokl. Earth Sci. A 407 (3), 491–494 (2006).
M. Merry and A. le Roex, S. Afr. J. Geol. 110, 597–610 (2007).
D. R. Bell and R. O. Moore, S. Afr. J. Geol. 107, 59–80 (2004).
N. V. Sobolev, Y. G. Lavrent’ev, N. P. Pokhilenko, and L. V. Usova, Contrib. Mineral. Petrol. 40, 39–52 (1973).
W. F. McDonough and S.-S. Sun, Chem. Geol. 120, 223–253 (1995).
E. V. Shchukina, A. M. Agashev, and N. P. Pokhilenko, Geosci. Front. 8 (4), 641–651 (2017). https://doi.org/10.1016/j.gsf.2016.08.005
J. Tuff and S. Gibson, Contrib. Mineral. Petrol. 153, 369–387 (2007).
M. Willbold and A. Stracke, Geochem., Geophys., Geosyst. 7 (4) (2006). https://doi.org/10.1029/2005GC001005(G3)
D. Weis, F. A. Frey, R. Schlich, M. Schaming, R. Montigny, D. Damasceno, N. Mattielli, K. P. Nicolaysen, and J. S. Scoates, Geochem., Geophys., Geosyst. 3 (6), 1–27 (2002).
S. Keshav, A. Corgne, G. H. Gudfinnsson, M. Bizmis, W. F. McDonough, and Y. Fei, Geochim. Cosmochim. Acta 69 (11), 2829–2845 (2005).
A. M. Agashev, N. P. Pokhilenko, E. Takazawa, J. A. McDonald, M. A. Vavilov, I. Watanabe, and N. V. Sobolev, Chem. Geol. 255 (3–4), 317–328 (2008).
FUNDING
This study was supported by the Russian Foundation for Basic Research, project no. 15–05–07758 and state assignment project of IGM SB RAS.
Author information
Authors and Affiliations
Corresponding author
Additional information
Translated by A. Larionov
Rights and permissions
About this article
Cite this article
Agashev, A.M. Geochemistry of Garnet Megacrysts from the Mir Kimberlite Pipe (Yakutia) and the Nature of Protokimberlite Melts. Dokl. Earth Sc. 486, 675–678 (2019). https://doi.org/10.1134/S1028334X19060126
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1028334X19060126