Lower-middle Devonian iron-bearing successions were studied along 2 measured stratigraphic sections in the Çamdağ region of NW Anatolia. Ironstones in the upper part of the Fındıklı Formation in Kabalakdere are characterized by alternating red and green mudstones and sandstones at the bottom, followed by a series of dolomite, dolomitic limestone with oolitic ironstones, and chamositic mudstones at the top. Conodonts from these carbonates indicate the delta-pesavis zones of the late Lochkovian. The 12to 45-m-thick Ferizli Formation unconformably overlies the Fındıklı Formation with a quartz-arenite succession at the bottom. The formation comprises alternating red, iron-rich limestones and dolomitic limestones, where iron-rich bioclastic grainstones are more dominant than iron-rich oolitic grainstones. The dolomitic limestones in this succession mark the ensensis and hemiansatus zones of the middle Givetian age. Mineralogically, the carbonates are dominated by goethitized and chamositized fossil fragments and chamositic oolites. In the oolitic facies, the oolites are made up of iron-bearing carbonates/iron, the bioclast of micritized/ironized brachiopods, and crinoids, whereas the matrix includes goethite, brown iron-silicates, chamosite, sideritic oolites, quartz clasts, and brachiopods. Partial iron precipitation within microborings or precipitation along the spine holes on echinoid grains is observed in the bioclastic grainstone/ biosparite facies. Iron peloids are also recognized in the grainstone facies. Iron precipitation could be explained as precipitation of transported and dissolved iron from a terrestrial environment under wet/subtropical climate conditions within oxidizing and increased pH conditions, or as dissolved iron transported by upwelling currents over the shelves and precipitated under an oxidizing environment. The cyclic occurrence of primary iron in a marine carbonate environment and its extensive distribution over large areas indicates that a controlling mechanism for iron-rich carbonates and mudstones could be related to the cooperation of climate, sea level, and oceanographic changes in the middle Givetian. During the late Lochkovian, the same or very similar controlling factors might have operated, where the alternation of red mudstones can be explained by lateral facies changes or changes in terrestrial/nutrient influx.
Devonian strata, including siliciclastic and carbonate rocks that were deposited in shallow marine to coastal environments, are widely distributed in the eastern Taurides of southern Turkey. To document the regional formation of the Givetian (Middle Devonian)/ Frasnian (Upper Devonian) boundary, a section in the eastern Taurides was studied in high resolution with regard to biostratigraphy, microfacies, sequence stratigraphy, and the global Frasne Event. The integrated biostratigraphic investigation was based on calcareous benthic foraminifers, ostracods, conodonts, and palynomorphs, which provide a biostratigraphic frame that allows to recognize the Givetian/Frasnian boundary. On the basis of the lithological variation in the outcrop as well as on depositional textures and biotic components as observed in thin sections, fourteen microfacies types of both siliciclastic and carbonate rocks can be distinguished. These microfacies are interpreted to have been deposited in settings that range from distal shelf to lagoonal depositional environments. The sequence stratigraphic interpretation allows to recognize two successive depositional sequences. The first one is a complete sequence including lowstand systems tract deposits, overlain by transgressive systems tract and highstand systems tract deposits. The second sequence is only represented by transgressive systems tract sediments. The Givetian/Frasnian boundary corresponds to the highstand systems tract of Sequence 1. The late Givetian Frasne Event can be detected lithologically and can be compared with other areas. Its position is confirmed biostratigraphically.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.