Insight into magma genesis at convergent plate margins - a case study from the eastern Pontides (NE Turkey)
Yükleniyor...
Tarih
2010
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
E Schweizerbartsche Verlagsbuchhandlung
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Convergent plate margins are the most intense areas of granitoid magmatism on Earth. The Eastern Pontide Magmatic Belt in NE Turkey represents a paleo-arc with numerous quartz diorite to syenite intrusions, ranging in age from 142 to 56 Ma and being composed of K-feldspar, plagioclase, quartz, pyroxene, hornblende, biotite, and Fe-Ti oxides. The granitoids exhibit low-to high-K calc-alkaline, metaluminous to slightly peraluminous I-type features and contain abundant mafic magmatic enclaves (MME). They are characteristically enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) relative to high field strength elements (HFSE). Chondrite-normalized REE patterns are fractionated (La-N/Lu-N = 1.49-17.4) with pronounced negative Eu anomalies (Eu/Eu* = 0.46-1.77). Initial Sr-87/Sr-86 values are between 0.7056 and 0.7079, and epsilon(Nd(i)) values between -5.3 and 1.6. Fractional crystallization, magma mixing/mingling and crustal contamination played an important role during magma evolution. All these characteristics, combined with the low values of K2O/Na2O, Mg-number, ASI and ratios of Al2O3/(FeOT+MgO+TiO2) and (Na2O+K2O)/(FeOT+MgO+TiO2), suggest an origin by dehydration melting of mafic (amphibolitic) or tonalitic lower crustal source rocks.
Açıklama
Anahtar Kelimeler
Cretaceous-Paleocene, Eastern Pontides, Sr-Nd-Pb isotopes, subduction, arc magmatism, U-Pb SHRIMP
Kaynak
Neues Jahrbuch Fur Mineralogie-Abhandlungen
WoS Q Değeri
Q4
Scopus Q Değeri
Q4
Cilt
187
Sayı
3
