Geochemistry and Petrogenesis of the Eastern Pontide Volcanic Rocks, Northeast Turkey
Küçük Resim Yok
Tarih
1997
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier GmbH
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
The eastern Pontides are characterized by three volcanic cycles erupted in Liassic, Upper Cretaceous and Eocene times. Volcanic rocks of Liassic age are transitional, those of Upper Cretaceous age are subalkaline, and Eocene volcanic rocks are alkaline around Trabzon and Tonya, but subalkaline in the south of Gümüşhane. Geochemical variations indicate that fractional crystallization played a significant role in the evolution of more differentiated rocks, especially in Liassic and Upper Cretaceous volcanic rocks. Fractionation of olivine, clinopyroxene and plagioclase was the major control in the evolution of Liassic volcanic rocks, whereas fractionation of plagioclase and clinopyroxene dominated in the Upper Cretaceous volcanic rocks. Liassic volcanics show high to low pressure fractionation but Upper Cretaceous volcanic rocks low pressure fractionation. Eocene volcanic rocks from Tonya exhibit high to low pressure whereas those from Trabzon low pressure fractionation. The volcanic rocks were possibly derived from a tholeitic to an E-type MORB source. The Eocene volcanic rocks around Trabzon have very high LILE and LREE concentrations compared to those of Tonya. This may be due to varying degrees of partial melting from a common source. The trace element patterns of Liassic volcanic rocks are very consistent with those of withinplate tholeites, suggesting that the Liassic volcanic rocks developed under an extentional regime, possibly related to rifting. However, Upper Cretaceous volcanic rocks are best represented by island-arc calcalkaline, and Eocene volcanic rocks by within-plate alkaline patterns. Hence, it may be implied that the subduction began in the Liassic after rifting, continued in the Upper Cretaceous and reached maturity with crustal thickening in the Eocene. These geochemical data together with geological data indicate an island arc setting for the Eastern Pontide volcanic rocks.
Açıklama
Anahtar Kelimeler
Kaynak
Chemie der Erde
WoS Q Değeri
Scopus Q Değeri
Q2
Cilt
57
Sayı
Künye
Arslan, M., Tüysüz, N., Korkmaz, S., Kurt, H., (1997). Geochemistry and Petrogenesis of the Eastern Pontide Volcanic Rocks, Northeast Turkey. Chemie der Erde, 57, 157-187.
