Contemporaneous alkaline and calc-alkaline series in Central Anatolia (Turkey): Spatio-temporal evolution of a post-collisional Quaternary basaltic volcanism

International audienceThis study focuses on spatio-temporal evolution of basaltic volcanism in the Central Anatolian post-collisionalQuaternary magmatic province which developed along a NE-SWorientation in Turkey. This magmatic provinceconsists of the stratovolcanoes Erciyes (ES) and Hasandag (HS), and the basaltic volcanic fields of Obruk-Zengen(OZ) and Karapınar (KA). The investigated samples range between basic to intermediate in composition(48–56 wt% SiO2), and exhibit calc-alkaline affinity at ES whereas HS, OZ and KA are alkaline in composition.Based on new K\\Ar ages and major element data, the oldest basaltic rock of ES is 1700±40 ka old and exhibitsalkaline character, whereas the youngest basaltic trachyandesite is 12 ± 5 ka old and calc-alkaline in composition.Most ES basaltic rocks are younger than 350 ka. All samples dated from HS are alkaline basalts, rangingfrom 543 ± 12 ka to 2 ± 7 ka old. With the exception of one basalt, all HS basalts are ~100 ka or younger inage. K\\Ar ages range from 797 ± 20 ka to 66 ± 7 ka from OZ. All the basalt samples are alkaline in characterand are older than the HS alkaline basalts, with the exception of the youngest samples. The oldest and youngestbasaltic samples from KA are 280± 7 ka and 163±10 ka, respectively, and are calc-alkaline in character. Basedon thermobarometric estimates samples from OZ exhibit the highest cpx-liqidus temperature and pressure. Forall centers the calculated crystallization depths are between 11 and 28 km and increase from NE to SW. Multistagecrystallization in magma chamber(s) located at different depths can explain this range in pressure. Harkervariation diagrams coupled with least-squaresmass balance calculations support fractional crystallization for ESand, to lesser extend for HS, OZ and KA. All basaltic volcanic rocks of this study are enriched in large-ion lithophileelements (LILE) and light rare earth elements (LREE). The lack of negative anomalies for high field strength elements(HFSE; Y, Yb) and the La/Nb N1 favor a shallow lithospheric source for ES, HS, OZ and KA basaltic volcanicrocks, whereas some samples bear the trace element signature of an asthenospheric mantle source. The lithosphericmantle beneath Central Anatolia may have not been affected from asthenospheric mantle directly. NegativeNb-Ta-Ti anomalies and a positive Pb spike of ES, HS, OZ and KAmay be ascribed to crustal contamination oras the imprints of the previous subduction processes. According to this study, and previous studies, the effect ofsubduction and/or crustal contamination in Central Anatolia decreased fromtheMiocene to the Quaternary, andthe origin of the Quaternary basaltic rocks mainly derived from subduction-related magmas enriched with sedimentinput rather than to slab-derived fluids. Our calculated eruption ages for the four basaltic complexes showthat spatial differences predominate, whereas temporal trends are difficult to discern due to limited age resolution.According to the available geochronological, petrological and geochemical data, alkaline and calc-alkalinevolcanism occurred simultaneously from distinct parental magma