Orta Anadolu da Konya'nın Batısındaki dalmabatma ile ilişkili volkanik kayaçların jeolojisi, petrografisi, ve jeokimyası

Year 2003, Volume: 46 Issue: 2, 39 - 52, 29.08.2003

Hüseyin Kurt Ali Müjdat Özkan Kerim Koçak

Abstract

Konya'nın KB'sı Neojen yaşlı volkanik breş, aglomera, tüfit, tüf ve andesit, dasit ve bazaltik andezit lavlarıyla kaplıdır. Bazaltik andezitler yaklaşık olarak % 7-10 olivin, %3-5 klinopiroksen, %5-10 ortopiroksen, %60-70 plajiyoklaz ve % 5-10 opak mineral fenokristalleri içerirken andezitik lavlar % 50-60 plajiyoklaz, % 10-15 hornblende, %5 biyotit, %2 klinopiroksen, %1 sanidin, %1 kuvars ve % 3 opak mineral oluşmaktadır. Dasitik kayaçlar %35-40 plajiyoklaz, % 10-15 kuvars, %15-20 hornblend, %10-12 biyotit, % 2-3 opak mineral, %3 sanidin içerirler Dasit ve andezitik kayaçlar salınım zonlanma ve elek dokusuna sahiptirler.  Volkanik kayaçların bileşimi bazallik andezitten dasite kadar değişir ve tipik bir kalkalkalin karakter gösterirler. Ana ve iz element içeriklerinin değişimi hornblend, plajiyoklaz, piroksen, ve titanlı magnetitin fraksiyonel kristalleşmesine ileri sürmektedir Plajiyoklaz farklılaşması zayıf negatif Eu anomalisinin gelişimi ile doğrulanmaktadır. Yüksek LREE/HREE ve LILE/HFSE oranları çalışılan örneklerin aktif kıta kenarında dalma batma ile ilişkili bir magmadan oluştuğunu göstermektedir Kayaçların oldukça farklılaşmış ve zengin RE E grafiği bu kayaçların oluşumunda kıta kabuğunun içerildiğine işaret etmektedir.

Keywords

Kalkalkalin, Dalma-Batma, Orta Anadolu, Volkanizma, Neojen

Geology, Petrography and Geochemistry of the Subduction Related Volcanic Rocks, West of Konya, Central Anatolia

Abstract

The northwest of Konya is covered by Neogene volcanic breccias, agglomerates, tuffites, tuffs and lavas of andesite, dacite and basaltic andesite. The basaltic andesites contain about 7-10% of olivine, 3-5 % clinopyroxene, 5-10 % orthopyroxene, 60-70 % plagioclase and 5-10 % opaque minerals while the andesitic lavas include 50-60 % plagioclase, 10-15 % hornblende, 5% biotite, 2 %, clinopyroxene, 1 % sanidine, 1 % quartz and 3 % opaque minerals. Main constituents in the dacitic rocks are plagioclase (35-40%), quartz (10-15 %), hornblende (15-20 %), biotite (10-12 %), opaque minerals (2-3%) and sanidine (3 %). The plagioclase in dacites and andesitic rocks have oscillatory zoning and sieve texture. The volcanic rocks range in composition from basaltic andesites to dacites with calc-alkaline character. Co-variation of major and trace element contents suggest fractional crystallization of hornblende, plagioclase, pyroxene and titaniferous magnetite. The plagioclase fractionation is confirmed by a slight development of negative Eu anomaly. High LREE/HREE and L1LE/ HFSE ratios show that the samples were possibly formed from a subduction-related magma at active continental margin. The strong fractionated and riched REE patterns of the rocks indicate that the formation of these rocks may have involved continental crust.

Keywords

Calcalkaline, Subduction, Central Anatolia, Volcanism, Neogene

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