Show simple item record

dc.contributor.authorDokuz, Abdurrahman
dc.contributor.authorAydınçakır, Emre
dc.contributor.authorKandemir, Raif
dc.contributor.authorKarslı, Orhan
dc.contributor.authorSiebel, Wolfgang
dc.contributor.authorDerman, Ahmet Sami
dc.contributor.authorTuran, Mehmet
dc.date.accessioned2020-12-19T19:49:40Z
dc.date.available2020-12-19T19:49:40Z
dc.date.issued2017
dc.identifier.citationDokuz, A., Aydınçakır, E., Kandemir, R., KArslı, O., Siebel, W., Derman, As., Turan, M. (2017). Late Jurassic Magmatism and Stratigraphy in the Eastern Sakarya Zone, Turkey: Evidence for the Slab Breakoff of Paleotethyan Oceanic Lithosphere. Journal of Geology, 125(1), 1-31.en_US
dc.identifier.issn0022-1376
dc.identifier.issn1537-5269
dc.identifier.urihttps://doi.org/10.1086/689552
dc.identifier.urihttps://hdl.handle.net/11436/2319
dc.descriptionKANDEMIR, RAIF/0000-0002-0344-9159en_US
dc.descriptionWOS: 000392384000001en_US
dc.description.abstractMiddle-Late Jurassic Cimmerian events in Turkey have been actively discussed in the past three decades, but proposed tectonic models associated with magmatism, metamorphism, and stratigraphic features remain controversial. To address this issue, Upper Jurassic mafic lavas are investigated at three locations (Alucra, Gumushane, and Olur) in the eastern Sakarya Zone, northeastern Turkey. These lavas are submarine and form planar flows parallel with the bedding plane in the Upper Jurassic carbonate sequence near the base or just below in the clastic sedimentary rocks. the basaltic lavas show calc-alkaline features and possess Nb-Ta values and Nb/U, Nb/La, and Ce/Pb ratios that are greater than those of island arc basalts. Multielement patterns are almost hump shaped, similar to ocean island basalts, which experience Pb depletion and weak negative Nb-Ta, Zr-Hf, and Ti anomalies. the low initial (Sr-87/Sr-86) ratios (0.70372-0.70554), positive initial epsilon(Nd) values (+2.7 to +4.4), and initial Pb isotope ratios that plot between mid-ocean-ridge and ocean island basalts are consistent with a melt derived from subcontinental lithospheric mantle, metasomatized by earlier fluids from subducted sediments and plume materials from the asthenosphere. Moderate Dy/Yb ratios with an average value of 1.8 imply partial melting in the spinel-garnet transition zone at depths of similar to 70-100 km. Slab breakoff is suggested as a geodynamic mechanism that accounts for these geochemical signatures. This inference is also favored by stratigraphic and sedimentologic evidence from the Upper Jurassic-Lower Cretaceous sedimentary rocks, which is consistent with short-lived vertical (epirogenic) movements in the region. Lower-Middle Jurassic sequences are transgressive, suggesting that subduction-related extension opened a backarc basin (Neotethys) in the south of the Sakarya Zone. Upper Jurassic-Lower Cretaceous carbonates point tectonically to tranquility during carbonate deposition in the Neotethys Ocean, which seems to have been achieved by complete closure of the Paleotethys in the north. About 15-20 m.yr. later (Kimmeridgian), after first carbonate deposition, intraplate-typemafic lavas ascended up to the shelf surface of the Neotethys. This was followed by formation of disconformity surfaces and then accumulation of coarse clastic sediments. All this points to a short-lived epirogenic movement that we ascribe to the breakoff of the southward-subducting Paleotethyan oceanic lithosphere in the Late Jurassic.en_US
dc.description.sponsorshipResearch Foundation of Karadeniz Technical University [2007.118.002.2, 2009.112-005-2]en_US
dc.description.sponsorshipThis research was supported by the Research Foundation of Karadeniz Technical University (2007.118.002.2and2009.112-005-2). E. Reitter is thanked for his help during the Sr-Nd-Pb isotope analyses. We wish to thank the reviewer, D. van Hinsbergen, and Editor D. Rowley, who provided many comments that improved the manuscript. We also wish to remember the sixth author of this essay, Ahmet Sami Derman, who died on May 18, 2012. He enabled us to become aware of the mafic rocks in this study during the fieldwork for his project on the Upper Jurassic-Lower Cretaceous carbonates of the Eastern Pontides.en_US
dc.language.isoengen_US
dc.publisherUniv Chicago Pressen_US
dc.rightsinfo:eu-repo/semantics/closedAccessen_US
dc.subjectKuzey Çin Kratonuen_US
dc.subjectKastamonu Granitoid Kemerien_US
dc.subjectYusufeli-Artvin Alanıen_US
dc.subjectPontides Ne Türkiyeen_US
dc.subjectVolkanik Kayalaren_US
dc.subjectTektonik Evrimen_US
dc.subjectGümüşhane Alanıen_US
dc.subjectJeodinamik Evrimen_US
dc.titleLate Jurassic Magmatism and Stratigraphy in the Eastern Sakarya Zone, Turkey: Evidence for the Slab Breakoff of Paleotethyan Oceanic Lithosphereen_US
dc.typearticleen_US
dc.contributor.departmentRTEÜ, Mühendislik ve Mimarlık Fakültesi, Jeoloji Mühendisliği Bölümüen_US
dc.contributor.institutionauthorKandemir, Raif
dc.identifier.doi10.1086/689552
dc.identifier.volume125en_US
dc.identifier.issue1en_US
dc.identifier.startpage1en_US
dc.identifier.endpage31en_US
dc.relation.journalJournal of Geologyen_US
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanıen_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record