Contrasting complexities in the evolution of calc-alkaline and alkaline melts of the Nigde volcanic rocks, Turkey: textural, mineral chemical and geochemical evidence


Aydin F.

EUROPEAN JOURNAL OF MINERALOGY, vol.20, no.1, pp.101-118, 2008 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 20 Issue: 1
  • Publication Date: 2008
  • Doi Number: 10.1127/0935-1221/2008/0020-1784
  • Journal Name: EUROPEAN JOURNAL OF MINERALOGY
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.101-118
  • Keywords: calc-alkaline magma, alkaline magma, magma mixing, polybaric crystallization, Nigde volcanic province, Turkey, MOUNT-ST-HELENS, EXPERIMENTAL PHASE-EQUILIBRIA, SOUFRIERE HILLS VOLCANO, IRON-TITANIUM-OXIDES, CENTRAL ANATOLIA, MAGMATIC SYSTEMS, AEOLIAN ISLANDS, ANDESITIC MAGMA, ASCENT RATES, CRYSTALLIZATION

Abstract

The Nigde volcanic province in central Turkey comprises four separate stratovolcanoes (Tepekoy, Cinarli, Melendiz and Keciboyduran) of Mio-Pliocene age (MPv) and several monogenetic cones of Pleistocene age (Pv). The MPv rocks are composed of large volume of andesitic lavas and pyroclastics with medium to high-K calc-alkaline character. They are strongly porphyritic with phenocryst assemblages of plag + opx + cpx + Fe-Ti oxides + bio +/- amph +/- quartz, and commonly exhibit disequilibrium textures such as complexly zoned plagioclases, reversely zoned pyroxenes, and reacted amphiboles and biotites. Geothermobaro-metric studies based on mineral chemistry data suggest that the MPv calc-alkaline magmas underwent a complex evolutionary history of cooling, crystallisation and mixing within two distinct magma chambers sited in the lower and in the upper crust, respectively.