Late Cretaceous volcanic arc magmatism in the Kale (Malatya, SE Türkiye) region of the Southeast Anatolian Orogenic Belt: Evidence from U-Pb Zircon age, Whole-rock and Sr-Nd Isotope geochemistry

Nurlu N., Köksal S., Kohut M.

9th Geochemistry Symposium with International Participation, Aydın, Türkiye, 17 - 21 Ekim 2022, cilt.1, ss.1-2

  • Yayın Türü: Bildiri / Özet Bildiri
  • Cilt numarası: 1
  • Basıldığı Şehir: Aydın
  • Basıldığı Ülke: Türkiye
  • Sayfa Sayıları: ss.1-2
  • Çukurova Üniversitesi Adresli: Evet

Özet

The voluminous intrusive and extrusive magmatism was formed in the Elazığ-Malatya region of the Southeast Anatolian Orogenic Belt (SAOB) as a consequence of the continental collision and/or convergent orogeny. The SAOB holds a great number of stratigraphic, metamorphic and tectonomagmatic units in the Elazığ-Malatya region that are crucial for recognition of the geodynamic setting of southeast Anatolia during the Upper Cretaceous. The Baskil Intrusive Complex (BIC) is composed of mainly tonalitic/granodioritic and dioritic/gabbroic plutonic rocks, while its sub-volcanic phase is represented by granophyre, aplite and microgabbro, which were intruded into the Upper Cretaceous supra-subduction zone (SSZ)-type İspendere ophiolites (SE Turkey). New U–Pb laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon data provided crystallization ages ranging from 84.3 to 81.5 Mafor the BIC. Mafic and felsic rocks of the BIC have a low- to medium-K calc-alkaline, I-type, metaluminous character, whereas extremely evolved felsic rocks of this complex show a peraluminous composition. The aluminium-in-hornblende barometery (~196 to 299 MPa) of magnesio-hornblendes in the Baskil intrusive rocks indicates their emplacement in the shallow- to moderate crustal plutonic levels at a minimum of 7.3 km to a maximum of 11.1 km depth. The Baskil intrusive rocks present depletion in Ti, Nb, Ta, light REE with respect to primitive mantle, and relative enrichment in large-ion lithophile element (Rb, Ba, Pb, Sr, Th), thus infer a pronounced subduction signature. Both mafic and felsic intrusives show low initial 87Sr/86Sr ratios (0.70357–0.70561) together with a high initial 143Nd/144Nd ratios (0.51279–0.51289), and high ƐNd(T) values (5.0–7.0) and relatively young Nd crustal residence model ages(TDM=0.31–0.48 Ga). Based on our field, mineralogical and geochemical findings, we suggest that the BIC was originated from an amphibolitic source that interacted with melts derived from a subducted oceanic plate within SSZ and was changed by fluids during the early stages of the short-lived volcanic arc magmatism that evolved at the fringe of the Tauride Platform.