Metamict gadolinite–(Y) from Ratnapura, Sri Lanka

Lutz Nasdala, Christoph Hauzenberger, Manfred Wildner, Chutimun Chanmuang N. (Korresp. Autor*in), K. A. Geeth Sameera

Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed

Abstract

A fairly large (ca. 15 cm), massive glassy specimen of nearly black bulk colour, found in Ratnapura district, was identified as metamict gadolinite–(Y) based on its chemical composition Y1.4Ln0.6Ca0.1Fe0.9Be2Si2O10 (with Ln = lanthanide elements La–Lu) and since the material reconstituted to monoclinic gadolinite–(Y) after two days of dry annealing in air at 1150 °C. Thin slabs (< 0.5 mm) of the specimen are bottle-green and transparent. Apart from surface weathering and small inclusions, the material is fairly homogeneous and does not show any indication of chemical alteration. Concentrations of Th (6310 ppm) and U (3360 ppm) in the material, and its calculated time-integrated alpha dose of ca. 8.5 × 1018 g–1 based on the 206Pb/238U age of ca. 518 Ma, explain the present glassy state as being caused by radioactive self-irradiation over geological periods of time.
OriginalspracheEnglisch
Seiten (von - bis)23-30
Seitenumfang8
FachzeitschriftJournal of the Geological Society of Sri Lanka
Jahrgang24
Ausgabenummer1
PublikationsstatusVeröffentlicht - 11 Okt. 2023

ÖFOS 2012

  • 104026 Spektroskopie
  • 105116 Mineralogie
  • 105113 Kristallographie

Zitationsweisen