Petrochemistry and Parent Rock Characteristics of the Amphibolites in the Gümüşler Formation of the Niğde Metamorphics, Central Turkey

In this study, it was attempted to determine the petrochcmistry and parent rock characteristics of the Gümüşler amphibolites, associatcd with marble and quartzite, from the Niğde metamorplıics by using tlıcir whole-rock chemical analyses. Amphibolites are associated with a seri es of Pre-Cretaceous supracmstal metasediınents of the Gümüşler Formation. Massive and variably foliated amphibolites are made up mainly by plagioclase, hornblende, quartz, diopsite witlı accessory sphene and apatite. Based on trace element characteristics, the amphibolites are suggested to be metaigneous roeks; tuff or less likely basaltic-andesitic lava/sili, which were emplaced between metasediınents. Their parent rocks are subalkalinc basalt and andesite in cnmposition, and are characterisedby high K2O, Rb, Sr, Ba, K/Rb (-270-550) ratin, and lowMgO, Ti,Y, Zr, CaO/Al2O3 ratio. Pctrochenıical dataalso suggcstthat the parent rocks of these ortho amphibolites were possibly founded by fractional crystallization of olivine, clinopyroxene and hornblende.