Magmatic garnet in deformed aplite dykes from the Mórágy granitoid, SE-Transdanubia, Hungary

Abstract

This paper is devoted to the description of spessartine-almandine garnet (Sps: 39.8-60.2%; Alm: 29.1-56.76%; Grs <7%, Prp <3.6%, Adr <5%) from aplitic dyke rocks of the Moragy granitoid near Erdosmecske and Aranyos valley. The aplitic dyke rocks contain K-feldspar, plagioclase, quartz, (myrmekite), ±garnet, ±biotite, chlorite or secondary muscovite, ±ore minerals, ±calcite, ±apatite and ±epidote. Two different zoning types in garnet were detected by electron microprobe. Zoning type I means either Mn enrichment at the expense of Fe towards the rim or towards the core or plateau garnet profiles. Zoning type II displays Ca enrichment at the rim of garnet. A high proportion of Sps component in garnet and the character of zoning type I are considered as typical magmatic features.  The pressure-temperature estimation for aplite formation arises from experimental investigations of Green (1977) in agreement with the hypothetical approach of liquidus relationships by Abott and Clarke (1979) giving a minimum temper...