Geochemistry and provenance of Maastrichtian clastic rocks in the Dikmendede formation of Orhaniye in Kazan-Ankara-Turkey region
Küçük Resim Yok
Tarih
2011
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Wiley-Blackwell Publishing Asia
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
An integrated petrographic and geochemical study of the sandstones of the Maastrichtian-aged in the Orhaniye (Kazan-Ankara-Turkey) was carried out to obtain more information on their provenance, sedimentological history and tectonic setting. Depending on their matrix and mineralogical content, the Maastrichtian sandstones are identified as lithic arenite/wacke. The Dikmendede sandstones derived from types of provenances, the recycled orogen and recycled transitionaI. The chemical characteristics of the Dikmendede sandstones, i.e., fairly uniform compositions, high Th/U ratios (>3.0), negative Eu anomalies (Eu/Eu* 0.72-0.99) and Th/Sc ratios (mostly less than 1.0), favor the OUC (old upper continental crust) provenance for the Dikmendede sandstones. The SiO2/Al2O3, Th/Sc (mostly <1.0) and La/Sc (<4.0) ratios are; however, slightly lower than typical OUC, and these ratios may suggest a minor contribution of young arc-derived material. The rare earth element (REE) pattern, and La/Sc versus Th/Co plot suggests that these sediments were mainly derived from felsic source rocks. The Dikmendede sandstones have high Cr (123-294 ppm) and Ni (52-212 ppm) concentrations, Cr/Ni ratio of 1.93, and a medium correlation coefficient between Cr and Ni and corresponding medium to high correlation of both (Cr and Ni, respectively) elements with Co. These relationships indicate a significant contribution of detritus froni 0phi0Utic rocks. As rare earth element data are available for the Dikmendede sandstones, the Eu/Eu* is compared with LaN/YbN. Samples plot in the area of overlapping between continental collision, strike-slip and continental arc basins. The predominantly felsic composition of the Dikmendede sandstones is supported by the REE plots, which show enriched light REE, negative Eu anomaly and flat or uniform heavy REE. The Dikmendede sandstones have compositions similar to those of the average upper continental crust and post-Archean Australian shales. This feature indicates that the sediments were derived mainly from the upper continental crust. The Dikmendede sandstones have chemical index of alteration (CIA) values of 28-49, with an average of 40 indicating a low degree of chemical weathering in the source area. The compositional immaturity of the analyzed sandstone samples is typical of subduction-related environments, and their SiO2/Al2O 3 and K20/Na20 ratios and Co, Sc, Th and Zr contents reflect their oceanic and continental-are settings. The Dikmendede sandstones were developed as flysch deposits derived from mixed provenance in a collision belt.
Açıklama
Anahtar Kelimeler
Dikmendede, Flysch, Orhaniye, Provenans, Sandstone
Kaynak
Acta Geologica Sinica
WoS Q Değeri
Q3
Scopus Q Değeri
Q3
Cilt
85
Sayı
5
