Presentation on theme: "K/Ar dating of granitoids unravelling stages of the Neo- Tethyan convergence in the eastern Pontides and central Anatolia, Turkey D. Boztug* and Y. Harlavan**"— Presentation transcript:
K/Ar dating of granitoids unravelling stages of the Neo- Tethyan convergence in the eastern Pontides and central Anatolia, Turkey D. Boztug* and Y. Harlavan** * Dept. of Geological Engineering, Cumhuriyet University, 58140 Sivas, Turkey **Geological Survey of Israel, 30 Malkhe Israel St. 95501, Jerusalem
U/Pb, Rb/Sr, K/Ar, 40Ar/39Ar and Fission-Track geothermochronology, Oxygen and Sulfur isotope geochemistry providing the undercooling and exhumation history of some granitoids from Central and Western Anatolia, Turkey. CÜBAP – M-255 K/Ar, 40Ar/39Ar, Fission-Track Geochronology, Sr and Nd Isotope Geochemistry and Crystal Size Distribution Study of some Granitiods from the Central and Central-Eastern Anatolia, Turkey. TUBITAK-YDABAG-102 Y 149
1. Cumhuriyet Univ. Sivas, Turkey 2. Max-Planck Institute for Nuclear Physics, Heidelberg-Germany 3. TU Bergakademie der Freiberg-Germany 4. Geological Survey of Israel, Jerusalem 5. University of Nevada, Reno, USA 6. CNR-Inst. Geochr. Isotope Geochem. Pisa, Italy 7. Univ. of Quebec, Chicutimi, Canada
K/Ar dating was preformed on well- preserved igneous provinces associated with various stages of the neo-Tethyan closure in the northeastern, central and central-eastern Anatolia, Turkey. The pre-, syn- to post-collisional convergence between the Eurasian plate and Tauride- Anatolide platform are responsible for igneous bodies of Cretaceous to early Tertiary age.
1. late Cretaceous to early Paleocene arc-related I- type granites, 2. late Cretaceous syn-collisional S-type granites, 3. late Cretaceous post-collisional distensional- related high-K calcalkaline I-type monzonites, 4. late Cretaceous to Paleocene post-collisional distesional-related (I) ALKOS felsic A-type (II) ALKUS mafic A-type intrusives, 5. Paleocene post-collisional distensional- related ALKOS A-type syenites-monzonites 6. middle to late Eocene post-collisional extensional-related calcalkaline I-type granodiorite-tonalites.
In order to get the cooling age of some of these granitoids units, mineral separates, consisting of biotite, hornblende and their mixture have been dated using K-Ar method at the Geological Survey of Israel, Jerusalem.
The results support and confirm the spatial and temporal relationship between igneous activity and geodynamics of the Neo-tethyan convergence system in NE and central Anatolia, as suggested by some works.
These ages indicate that syn-collisonal compressional regime prevailed in Central Anatolia during the Senonian leading to the formation of S-type, peraluminous granitic association when the northward subduction was going on by producing the extensional-arc magmatism which has ceased in the early Palaeocene in NE Anatolia.
The post-collisonal distensional regime seems to occur between late Cretaceous to early Paleocene. This stage induced I-type, high-K calcalkaline hybrid magma source with a contribution of co-eval underplating mafic magma interacting with crustal felsic magma. the within-plate, A-type bi-modal intrusive has been formed from two distinct magma sources crustal-derived felsic and mantle-derived mafic components which have also been affected by magma mingling and mixing processes.
The main difference in the genesis of the I- and A-type magma sources in the same geodynamics and time span can be attributed either by the type and degree of partial melting or by the composition of source material (mantle or crust)
O and S isotope geochemistry of some S-I-A type granitoids derived from the syn- to post-collisional stages of the Neo-Tethyan convergence system in central Anatolia, Turkey Durmuş Boztuğ* and Greg B. Arehart** *Dept. of Geological Engineering, Cumhuriyet University, 58140 Sivas, Turkey **Department of Geological Sciences, University of Nevada, Reno, 89557-0138
Feldspars and/or quartz grains were analyzed for plutons from each of these suites, and are considered representative δ18OVSMOW values of average pluton.
Analyses were done at the University of Nevada, Reno, USA using laser-assisted fluorination techniques; mass spectrometry was done on a Micromass Prism using O2 gas as the analyte. Precision on individual analyses is ± 0.15‰.
Total sulfur was extracted from whole-rock powders using the Kiba method (ref) and sulfur isotope analyses performed on a continuous-flow Micromass Prism mass spectrometer using SO2 gas as the analyte. Precision on sulfur isotope analyses is ± 0.25‰.