A mantle- and a lower crust-derived bimodal suite in the Yusufeli (Artvin) area, NE Turkey: trace element and REE evidence for subduction-related rift origin of Early Jurassic Demirkent intrusive complex

Abstract

The Yusufeli area, in the Eastern Black Sea Region of Turkey, contains a crystalline complex that intruded into the Carboniferous metamorphic basement and is composed of two intrusive bodies: a gabbro-diorite and a tonalite-trondhjemite. The mafic body (45-57 wt% SiO 2 ) displays a broad lithological spectrum ranging from plagioclase-cumulate to quartz diorite.

Petrochemistry of the Siah-Kuh granitoid stock southwest of Kerman, Iran: Implications for initiation of Neotethys subduction

“…This indicates necessity of an additional process in the generation of the felsic rocks. On the other hand, partial melts, particularly from tholeiitic basalts and to lesser extent calc-alkaline basaltic amphibolites, yield parent magmas that have lower K 2 O and higher SiO 2 contents (Dokuz et al, 2006), similar to Siah-Kuh granitoid stock. Their low Al 2 O 3 (<15 wt%), low Sr contents, lack of any prominent Eu anomaly, flat to slightly LREE enrichment and flat HREE patterns suggest their formation at low pressure (65 kbar) and presence of plagioclase and lack of garnet as a residue in their genesis (Rapp et al, 1991;Beard and Lofgren, 1989;Springer and Seck, 1997).…”

“…The lack of Eu anomalies in the least fractionated granodiorite of the felsic intrusion reflects the absence of differentiation in terms of plagioclase extraction in mafic parent melt. In order to evolve to a granodiorite from mantle-derived basic parental magma would require a prominent fractionation (Dokuz et al, 2006). Low MgO concentrations of the samples of the felsic intrusion and other geochemical parameters rule out a direct derivation from mantle wedge.…”

Relative contributions of crust and mantle to generation of Campanian high-K calc-alkaline I-type granitoids in a subduction setting, with special reference to the Harşit Pluton, Eastern Turkey

“…These are the hintermost parts of the Eastern Anatolian Accretionary Complex. Late Mesozoic and early Cenozoic times are recorded by volcanic and granitoidic rocks (e.g., Tokel 1977;Yilmaz and Boztug 1996;Boztug et al 2004;Karsli et al 2007;Kaygusuz et al 2008) The granitoid bodies occurred in various geodynamic settings and have different ages (e.g., Moore et al 1980) and compositions (Yilmaz and Boztug 1996;Karsli et al 2002;Topuz et al 2005;Boztug et al 2006;Dokuz et al 2006). The emplacements took place during the processes of crustal thickening related to the arc-continent collision and subsequent post-collisional extensional regimes (e.g., Yilmaz and Boztug 1996;Karsli et al 2004a, b;Topuz et al 2005).…”

“…Several plutons were studied to identify their genesis and the geodynamics of the eastern Pontides (e.g., Yilmaz and Boztug 1996;Karsli et al 2004a, b;Boztug et al 2004Boztug et al , 2006Topuz et al 2005;Dokuz et al 2006Dokuz et al , 2010Karsli et al 2007;Kaygusuz et al 2008;Dokuz 2009), but little effort has been made to combine the tectonic and petrological data in order to contribute to the understanding of the geodynamic evolution of the Eastern Pontides. The isotopic and geochronological data in the region are very limited.…”

Geochemistry and geodynamic implications of the Triassic bimodal magmatism from Western Kunlun Orogen, northwest China

“…The mafic rocks in such bimodal suites developing in subduction settings are usually highly sodic and have important contribution from the ''MORB'' type source, displaying positive eNd(t) values (e.g. Wever and Storey 1992;Tamura and Nakamura 1996;Pin and Paquette 1997;Shinjo et al 1999;Shinjo and Kato 2000;Dokuz et al 2006). However, our studies revealed that the mafic rocks in Taer are largely potassium rich, with negative Nd isotopic signatures, and were derived from partial melting of enriched continental lithospheric mantle, with no evident contributions from depleted MORB mantle.…”