Agostini, S.

Conticelli, S.

Di Giuseppe, P.

Di Vincenzo, G.

Manetti, P.

Savascin, M. Y.

English

Florence Research

Geophysical Research AbstractsVol. 21, EGU2019-8741, 2019EGU General Assembly 2019© Author(s) 2019. CC Attribution 4.0 license.From subduction- to strike slip-related volcanism: Miocene to Plioceneactivity in Sivas-Malatya region, Central-Eastern AnatoliaPaolo Di Giuseppe (1,2), Samuele Agostini (1), Gianfranco Di Vincenzo (1), Piero Manetti (1,3), Mehmet YilmazSavascin (4), Sandro Conticelli (3,5,6)(1) Istituto di Geoscienze e Georisorse, CNR di Pisa, Italy, (2) Dipartimento di Scienze della Terra, Università di Pisa, Pisa,Italy, (3) Dipartimento di Scienze della Terra, Università di Firenze, Firenze, Italy, (4) Jeoloji Mühendislig˘i, MunzurÜniversitesi, Tunceli, Turkey, (5) Istituto di Geoscienze e Georisorse, CNR di Firenze, Italy, (6) Istituto di GeologiaAmbientale e Geoingegneria, IGAG, Monterotondo, ItalyCentral-Eastern Anatolia volcanic activity recorded long-term geochemical history linked to the geodynamic evo-lution of the region. There, abundant orogenic magmatism resulted from the convergence of the Arabian platetowards the Eurasian one, which finally collided and sutured along the Bitlis Zagros Suture Zone (late Eocene-early Miocene). After this, in several locations of the Central-Eastern Anatolia, scattered intraplate-type basalticvolcanism developed along transtensional strike-slip faults, linked with the North Anatolian, the East Anatolianand Central Anatolian Fault Zones.In the study area, located in between the Kizilirmak and Malatya-Ovacik strike-slip faults, both calc-alkaline andalkaline rocks occur. Calc-alkaline volcanic activity developed during the early to late Miocene, with the Yamadagand Kepez Dag Volcanic Complexes (19-12 Ma), which were characterised by basaltic to rhyolitic products, withthe typical geochemical and isotopic characteristics of subduction-related magmas: Large Ion Lithophile Elementsenrichments, High Field Strength Elements depletions, with strong Nb-Ta negative anomalies, high 87Sr/86Sri(0.70400-0.70547) and low 143Nd/144Ndi (0.51261-0.51288).Coeval early-middle Miocene (16-13 Ma) basaltic lavas were emplaced, to form plateau-like structures along theKizilirmak strike-slip fault. These rocks are Na-alkaline basanites and alkali-basalts, showing in spite of theiralkaline character high LILE/HFSE ratios, high 87Sr/86Sri (0.70416-0.70554) and low 143Nd/144Ndi (0.51262-0.51284) isotopic composition, indicating the persistence of a relict subduction-related geochemical signature.Middle Miocene (∼10 Ma) alkaline basaltic volcanic rocks from Arguvan were erupted as less small linearlava flows aligned along the Malatya-Ovacik strike slip fault. They range from alkaline basalts to mugearites,and show different geochemical and isotope characteristics with respect to the older volcanic rocks. PrimordialMantle-normalised trace element diagrams show bell-shaped patterns typical of intra-plate volcanic rocks. Thelow 87Sr/86Sri (0.70348-0.70385) and high 143Nd/144Ndi (0.51278-0.51292) isotopic ratios suggest a contributionfrom a sub-lithospheric mantle. However, trace element compositions and enrichment in fluid-mobile elementsdisplay that also the Arguvan mantle source was affected by a previous subduction event.During the Pliocene (6-4 Ma), scattered basaltic lava flows erupted within the Kangal basin. These rocks are K-alkaline, ranging from alkaline basalts to shoshonite, showing high LILE/HFSE ratios, and Nb, Ta, and Ti troughsin Primordial Mantle-normalised trace element plots. Higher 87Sr/86Sri(0.70425-0.70522) and lower 143Nd/144Ndi(0.51263-0.51277) ratios with respect to Arguvan basalts suggest the involvement of a crustal component in theirgenesis. In this case crustal contamination en-route to the surface rather than recycling in the mantle source isinferred on the basis of petrographic characteristics and numerical modelling.In summary, a transition from calc-alkaline to Na-alkaline volcanic rocks is observed with time related to thegeodynamic evolution of the region. Early-middle Miocene orogenic magmas are typical arc volcanics, whereasalkaline magmas from Sivas, Arguvan and Kangal, mark the change from compressional to strike slip tectonicregime at the beginning of the late Miocene, with the development the Kizilirmak fault and the Malatya-Ovacikfault zone that favoured local upwelling of sub-lithospheric mantle. The apparent subduction-related signaturein the youngest activity of the Kangal is ascribed to crustal contamination rather than a renewal of subductioncomponents.

From subduction- to strike slip-related volcanism: Miocene to Pliocene activity in Sivas-Malatya region, Central-Eastern Anatolia

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From subduction- to strike slip-related volcanism: Miocene to Pliocene activity in Sivas-Malatya region, Central-Eastern Anatolia

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