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GEOREF RECORD

Synneusis of zircon; why not?

P. Alexandrov
Synneusis of zircon; why not?
Mineralogical Magazine (February 2001) 65 (1(428)): 71-79

Abstract

Some zircons from the Hercynian Soultz granite, NE France, exhibit complex structures, with double cores and oscillatory-banded overgrowths. These glomeroporphyritic crystals are uncommon for zircons, in which synneusis has not previously been described. The cores of the zircons are considered to correspond to very quickly formed {100} or {110} prisms. These could slowly sediment in the magma chamber and cluster together while sinking. The overgrowth rims correspond to a slower growth rate. U/Pb ion-probe dating of the cores and the overgrowth rims provided the same age of 327+ or -6 Ma. Chemical electron microprobe analyses indicated that cores and rims have the same composition for major and trace elements. The sinking of zircons accounts for the abnormally high percentages of zircon in the lower parts of the granite. The formation of clusters in the early stages of crystallization needs stable P/T conditions, a hot, liquid silicate melt with a high fluid content, and no other minerals crystallizing (liquidus phase).


ISSN: 0026-461X
EISSN: 1471-8022
Coden: MNLMBB
Serial Title: Mineralogical Magazine
Serial Volume: 65
Serial Issue: 1(428)
Title: Synneusis of zircon; why not?
Author(s): Alexandrov, P.
Affiliation: CRPG-CNRS, Vandoeuvre, France
Pages: 71-79
Published: 200102
Text Language: English
Publisher: Mineralogical Society, London, United Kingdom
References: 14
Accession Number: 2001-034750
Categories: Mineralogy of silicatesIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables
N48°55'60" - N48°55'60", E07°52'60" - E07°52'60"
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 200111
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