Age and significance of amphibolites in the bolu massif (İstanbul Zone, NW Turkey)

dc.contributor.advisor Topuz, Gültekin
dc.contributor.advisor Wang, Jia-Min
dc.contributor.author Demirkaya, İnal
dc.contributor.authorID 602191003
dc.contributor.department Geodynamics
dc.date.accessioned 2024-11-18T13:03:33Z
dc.date.available 2024-11-18T13:03:33Z
dc.date.issued 2022-07-06
dc.description Thesis (M.Sc.) -- İstanbul Technical University, Graduate School, 2022
dc.description.abstract The Bolu Massif represents the Late Neoproterozoic crystalline basement of the Istanbul Zone (NW Turkey), and is made up of two tectonometamorphic units which are separated by a major tectonic line. The lower tectonometamorphic unit comprises amphibolite-facies metamorphic rocks which are dominated by the migmatitic amphibolite and locally trondhjemite. On the other hand, the overlying tectonometamorphic unit comprises greenschist-facies mafic to felsic metavolcanic rocks intruded by a huge granitoid of Late Neoproterozoic age. This study deals with the metamorphic evolution of the underlying amphibolite-facies tectonometamorphic unit. The amphibolite-facies tectonometamorphic unit comprises migmatitic amphibolite (ca. 80% of the exposure area) and concordant to crosscutting trondhjemite sills/dykes/stocks (ca. 20% of the exposure area). Although this amphibolite unit was formerly interpreted to the crustal part of an ophiolite, rare earth element patterns and multi-element variation diagrams involving fluid immobile elements differ from the well-documented ophiolites. The geochemical features of these voluminous amphibolites are more consistent with those in intra-oceanic arcs and magmatic arcs. U-Pb dating of zircons from four trondhjemite samples and from three amphibolite samples consistently yielded ages of 255-260 Ma (Middle to Late Permian). Only zircons from one amphibolite sample defined a discordia with an upper intercept age of 554 ± 34 Ma (2) (Late Neoproterozoic-Cambrian). The geochronological data shows that the amphibolite-facies tectonometamorphic unit does not represent the Late Neoproterozoic basement of the Istanbul Zone. It is related to Late Palaeozoic to Late Mesozoic orogenic events.
dc.description.degree M.Sc.
dc.identifier.uri http://hdl.handle.net/11527/25644
dc.language.iso en_US
dc.publisher Graduate School
dc.sdg.type Goal 7: Affordable and Clean Energy
dc.sdg.type Goal 14: Life Below Water
dc.subject Bolu massif
dc.subject Bolu masifi
dc.subject Amphibolites
dc.subject Amfibolitler
dc.title Age and significance of amphibolites in the bolu massif (İstanbul Zone, NW Turkey)
dc.title.alternative Bolu masifi'ndeki (İstanbul Zonu, KB Türkiye) amfibolitlerin yaşı ve önemi
dc.type Master Thesis
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