Petrogenesis of the late Cretaceous K-rich volcanic rocks from the Central Pontide orogenic belt, North Turkey
Küçük Resim Yok
Tarih
2014
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
WILEY
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Subduction-related volcanic rocks are widespread in the Central Pontides of Turkey, and represented by the Hamsaros volcanic succession in the Sinop area to the north. The volcanic rocks display high-K calc-alkaline, shoshonitic and ultra-K affinities. 40Ar/39Ar age data indicate that the rocks occurred during the Late Cretaceous (ca 82Ma), and the volcanic suites were coeval. Primitive mantle-normalized trace element patterns of all the lavas are characterized by strong enrichments in large ion lithophile elements (LILE) (Rb, Ba, K, and Sr), Th, U, Pb, and light rare earth elements (LREE; La, Ce) and prominent negative Nb, Ta, and Ti anomalies, all typical of subduction-related lavas. There is a systematic increase in the enrichment of incompatible trace elements from the high-K calc-alkaline lavas through the shoshonitic to the ultra-K lavas. In addition, the shoshonitic and ultra-K lavas have significantly higher 87Sr/86Sr (0.70666-0.70834) and lower 143Nd/144Nd (0.51227-0.51236) initial ratios than coexisting high-K calc-alkaline lavas (87Sr/86Sr 0.70576-0.70613, 143Nd/144Nd 0.51245-0.51253). Geochemical and isotopic data show that the shoshonitic and ultra-K rocks cannot be derived from the high-K calc-alkaline suite by any shallow level differentiation process, and point to a derivation from distinct mantle sources. The shoshonitic and ultra-K rocks were derived from metasomatic veins related to melting of recycled subducted sediments, but the high-K calc-alkaline rocks from a lithospheric source metasomatized by fluids from subduction zone.
Açıklama
Anahtar Kelimeler
Central Pontide, mantle metasomatism, shoshonite, subduction, Turkey, ultra-potassic
Kaynak
ISLAND ARC
WoS Q Değeri
Q3
Scopus Q Değeri
Q1
Cilt
23
Sayı
2
