Mineralogy, geochemistry, and Sr-Nd isotopes of the Cretaceous leucogranite from Karamadaz (Kayseri), central Turkey: implications for their sources and geological setting
Küçük Resim Yok
Tarih
2008
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
CANADIAN SCIENCE PUBLISHING
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
The leucogranite is the major constituent of the bimodal Late Cretaceous Karamadaz granitoid, developed in relation with evolution of the Inner Tauride Ocean along the northern margin of the Taurides in central Turkey. New analyses of minerals major and trace elements (including rare-earth elements (REE)), and of Sr and Nd isotopes are performed to determine the origin and geochemical characteristics of the leucogranites. Medium-coarse-grained leucogranite contains normally zoned plagioclase (An(12-20)), mildly alkaline biotite, and xenocrystic magneziohornblende, actinolite, and ferrohornblende. It is characterized by concave-up REE patterns with respect to middle-heavy REE. Field relations, mineral chemistry, geochemical data, and isotopic data suggest that the leucogranite could have originated from an amphibole-bearing igneous source in lower to middle crust by low-rate partial melting (< 40%) under low pressure and low H2O activity conditions, possibly coupled by mixing-mingling with mafic magma and high-level feldspar and minor biotite fractionation. In contrast, the quartz diorite and mafic microgranular enclave (MME) are probably developed from an enriched mantle, with possible mingling-mixing. MME, quartz diorite, and leucogranite may represent a magmatic suite, which formed in an extensional tectonic regime by bimodal magmatic activity probably because of lithospheric delamination or slab break off or after the Alpine thicken within the Gondwanan Tauride-Anatolide platform. Initial Sr data exhibit an age of 65 +/- 13 Ma for the leucogranite, but it does not indicate a true intrusion age of the magma due to isotopic modification of the magma.
Açıklama
Anahtar Kelimeler
Kaynak
CANADIAN JOURNAL OF EARTH SCIENCES
WoS Q Değeri
Q3
Scopus Q Değeri
Q2
Cilt
45
Sayı
8
