Baddeleyite containing ordered srilankite (ZrTi₂O₆) from Eppawala, Sri Lanka

Autor(en)

Lutz Nasdala, Gerald Giester, Chutimun Chanmuang N., Christoph Hauzenberger, Fabien Pascale, Roberto Dovesi, G.W.A. Rohan Fernando, Sameera Kasthuri Arachchige, Martin Ende, Gerlinde Habler

Abstrakt

Megacrysts of baddeleyite have been found in a (latest Neoproterozoic) carbonatite near Eppawala, Sri Lanka. The material was characterised using a combination of structural, chemical and spectroscopic analysis techniques, revealing notable internal heterogeneity. The baddeleyite contains variable, significant volume fractions affected by secondary alteration. Further detailed studies will be needed before the material can be considered as potential primary reference material in U-Pb and other isotope-analytical studies. Most remarkable, however, is the occurrence of lamellae of ordered ZrTi₂O₆ (orthorhombic space group Pbcn with a = 14.198 ± 0.002 Å, b = 5.326 ± 0.001 Å, c = 5.002 ± 0.001 Å). Single-crystal X-ray diffraction and Raman microspectroscopy results, including a calculated spectrum, are presented for the newly recognised ordered form of ZrTi₂O₆. In this phase, Zr is eight- and Ti is six-coordinated. It seems to be a hitherto unknown polymorph: So far, only disordered ZrTi₂O₆ with both Zr and Ti in octahedral sites was known to occur in nature. Revisiting known srilankite samples appears worthwhile.

Organisation(en)

Institut für Mineralogie und Kristallographie, Department für Lithosphärenforschung

Externe Organisation(en)

NAWI Graz Geozentrum, Université de Lorraine, Accademia delle Scienze di Torino, The Open University of Sri Lanka, Geological Survey and Mines Bureau, Martin-Luther-Universität Halle-Wittenberg

Journal

Lithos

Band

2025

Anzahl der Seiten

10

ISSN

0024-4937

DOI

https://doi.org/10.1016/j.lithos.2025.108230

Publikationsdatum

12-2025

Peer-reviewed

Ja

ÖFOS 2012

105116 Mineralogie, 105113 Kristallographie, 104026 Spektroskopie

Schlagwörter

ASJC Scopus Sachgebiete

Geology, Geochemistry and Petrology

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/fc1f8dad-836f-461e-a32e-fd13d335ee7a