Petrology and Geochemistry of Post-Collisional Early Miocene Volcanism in the Karacadag Area (Central Anatolia, Turkey)
Küçük Resim Yok
Tarih
2011
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
WILEY-BLACKWELL
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Early Miocene (ca. 21-18 Ma) volcanism in the Karacadag area comprises three groups of volcanic rocks: (1) calcalkaline suite (andesitic to rhyolitic lavas and their pyroclastics), (2) mildly-alkaline suite (alkali basalt, hawaiite, mugearite, benmoreite and trachydacite), and (3) a single trachyandesitic flow unit. Field observations, (40)Ar/(39)Ar ages and geochemical data show that there was a progressive temporal transition from group 1 to 3 in a post-collisional tectonic setting. The cakalkaline suite rocks with medium-K in composition resemble those of subduction-related lavas, whereas the mildly-alkaline suite rocks having a sodic tendency (Na(2)O/K(2)O=1.5-3.2) resemble those of within-plate lavas. Incompatible element and Sr-Nd isotopic characteristics of the suites suggest that the lithospheric mantle beneath the Karacadag area was heterogeneously enriched by two processes before collision: (1) enrichment by subduction-related processes, which is important in the genesis of the calcalkaline volcanism, (2) enrichment by small degree melts from the astenosphere, which dominates the mildly alkaline volcanism. Perturbation of the enriched lithosphere by either delamination following collision and uplift or removal of the subducted slab following subduction and collision (i.e., slab breakoff) is the likely mechanism for the initiation of the post-collision volcanism.
Açıklama
Anahtar Kelimeler
post-collision, calcalkaline, Sr-Nd isotopes, Karacadag, Central Anatolia
Kaynak
ACTA GEOLOGICA SINICA-ENGLISH EDITION
WoS Q Değeri
Q3
Scopus Q Değeri
Q3
Cilt
85
Sayı
5
