Yaşar EREN, Aşçı Zülal TORAMAN, Kerim KOÇAK

Kocakızıl (Akşehir-Konya) doleritinin petrografik ve jeokimyasal özellikleri

Sultandağı'nda (Akşehir-Konya) Triyas (?) yaşlı dolerit dayk veya silleri başlıca plajiyoklaz (An58-67), ojit, az amfibol ve opak minerallerinden oluşmaktadır. Doleritik dokunun egemen olduğu kayaçlarda serisitleşme ve kloritleşme de izlenebilmektedir. Çeşitli jeokimyasal ayırtman diyagramlar yardımı ile yarıalkali magmatik kayaçların sınırlı kimyasal bileşim gösteren levha içi toleyitleri olduğu belirlenmiştir. Nadir toprak element (NTE) ve okyanus ortası sırtı bazaltlara (OOSB) oranlanmış bazı iz element diyagramlarında örneklerin uyumluluğu ve Zr'un bazı ana ve iz elementlerle olan çizgisel ilişkisi bunların aynı kökene sahip olduğunu ve safhalı kristalleşmenin onların petrolojik tarihçelerinde önemli bir rol oynadığını göstermektedir. Örneklerin mineral kimyası, iz element ve NTE içeriklerine dayanarak doleritlerin, Torid-Anatolid platformunun yüksek oranda yayılıp açılması ve Neotetis okyanusunun gelişimi ile ilişkili olarak muhtemelen zenginleşmiş bir mantodan, yüksek derecelerdeki kısmi ergime ile türediği ve olivin ve/veya piroksen farklılaşmasına uğradığı ileri sürülmüştür.

Petrographical and geochemical characteristics of the Kocakızıl (Akşehir-Konya) dolerites

Triassic dolerite dykes or sills at Sultandağı (Akşehir, Konya) area are mainly made up of plagioclase (An58-67), augite, rare amphibole, and opaque iron ore. Sericitisation and chloritisation exist in the samples, in which doleritic texture is dominant. By some geochemical discriminating diagrams, the subalkaline magmatic rocks were determined to be within-plate tholeiites with restricted chemical composition. Compatibility of the samples in the NTE and OOSB-normalized some trace element diagrams as well as existence of linear relation of Zr with some major and trace elements, show that they are of co-genetic and fractional crystallization (e.g. pyroxene and/or olivine) process could play an important role in their petrological history. Based on mineral chemistry, trace element and NTE contents of the samples, the dolerites were suggested to be derived from possibly an enriched mantle, by high degree partial melting, and undergone fractional crystallization of olivine and/or pyroxene in relation with higher rates of extension and rifting of Tauride—Anatolide platform and consequently development of Neotethyan ocean.

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