MINERALOGIA, 50, No 1-4: 13-33 (2019) DOI: 10.2478/mipo-2019-0002 www.Mineralogia.pl MINERALOGICAL SOCIETY OF POLAND POLSKIE TOWARZYSTWO MINERALOGICZNE Original paper Lamprophyric rock locations in Greece ٭1 Ioannis-Nektarios G. Kamvisis 1 Consultant Geologist’s office, Greek Ministry of Defence, 227 Mesogion av., Athens, Greece * Correspondence: e-mail:
[email protected] Received: June 6, 2019 Received in revised form: September 10, 2019 Accepted: September 11, 2019 Available online: November 1, 2019 Abstract. Twenty-four areas with lamprophyric formations have been located through a bibliographic search in Macedonia, Thrace, the islands and Attica. Most lamprophyre types have been identified including rare “alkali minette”. In most localities the dikes/sills appear to be late mantle products associated with deep faulting following extensional activity in granitoids. Key-words: lamprophyric rocks, distribution, Greece, bibliography 1. Introduction According to the Glossary of Geology (Neuendorf et al. 2005) the term lamprophyric describes rocks with holocrystalline-porphyritic texture exhibited by lamprophyres in which mafic phenocrysts occur in a fine-grained crystalline groundmass. Picritic rocks are excluded (Woolley et al. 1996). The word “lamprophyre”, first used by von Gumbel in 1874 for certain micaceous porphyritic dikes from the Bohemian massif, comes from the Greek word “lampros” which means bright. The ending – “phyre”-, which comes from “porphyry”-, describes the rock’s porphyritic nature. Lamprophyres are defined as mesocratic to melanocratic porphyritic hypabyssal rocks, containing mafic phenocrysts such as micas, amphiboles and to some extent clinopyroxene. Feldspars or foids are confined to the groundmass which may also contain any of the above mafic minerals. Geochemically, lamprophyres tend to have a higher K2O, Na2O, volatiles (H2O, CO2), S, P2O5 and Ba content than mineralogically similar rocks (Le Maitre 2002).