Sapphires related to alkali basalts from the Cerova Highlands, Western Carpathians (southern Slovakia): composition and origin

Uher, P., Giuliani, G., Szakall, S., Fallick, A.E., Strunga, V., Vaculovic, T., Ozdin, D. and Greganova, M. (2012) Sapphires related to alkali basalts from the Cerova Highlands, Western Carpathians (southern Slovakia): composition and origin. Geologica Carpathica, 63(1), pp. 71-82. (doi: 10.2478/v10096-012-0005-7)

Abstract

Blue, grey-pink and pink sapphires from the Cerová Highlands, Western Carpathians (southern Slovakia) have been studied using CL, LA-ICP-MS, EMPA, and oxygen isotope methods. The sapphire occurs as (1) clastic heavy mineral in the secondary sandy filling of a Pliocene alkali basaltic maar at Hajnáčka, and (2) crystals in a pyroxenebearing syenite/anorthoclasite xenolith of Pleistocene alkali basalt near Gortva. Critical evaluation of compositional diagrams (Fe, Ti, Cr, Ga, Mg contents, Fe/Ti, Cr/Ga, Ga/Mg ratios) suggests a magmatic origin for clastic blue sapphires with lower Cr and Mg, but higher Fe and Ti concentrations in comparison to the grey-pink and pink varietes, as well as similar compositional trends with blue sapphire from the Gortva magmatic xenolith. Moreover, blue sapphires show similar δ¹⁸O values: 5.1 ‰ in the Gortva xenolith, 3.8 and 5.85 ‰ in the Hajnáčka placer, closely comparable to mantle to lower crustal magmatic rocks. On the contrary, pink and grey-pink sapphires show higher Cr and Mg, but lower Fe and Ti contents and their composition points to a metamorphic (metasomatic) origin.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Fallick, Professor Anthony
• Authors: Uher, P., Giuliani, G., Szakall, S., Fallick, A.E., Strunga, V., Vaculovic, T., Ozdin, D., and Greganova, M.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Geologica Carpathica
• ISSN: 0016-7738
• Published Online: 31 January 2012