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Reconstructing the volcanic history of Ulukışla Caldera to improve the hazard assessment around the Hasandağ Volcanic Complex (Central Anatolia)

Rengin Özsoy1 , Ivan Sunyé-Puchol1, Xavier Bolós2, Efe Akkaş3, Antonio Costa4, Lorenzo Tavazzani5, Daniel P. Miggins6, Manuela Nazzari7, Olivier Bachmann5, Piergiorgio Scarlato7, Silvio Mollo1,7

  • Affiliations:  1Department of Earth Sciences, Sapienza University of Rome, 00185 Rome, Italy; 2Geoscience Barcelona (GEO3BCN), CSIC, Lluís Solé Sabarís s/n, 08028, Barcelona, Spain; 3Department of Geological Engineering, Hacettepe University, Beytepe, 06800 Ankara, Turkey; 4Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna, Bologna, Italy; 5Institute of Geochemistry and Petrology, ETH Zürich, Clausiusstrasse 25, CH-8092 Zurich, Switzerland; 6Argon Geochronology Laboratory, College of Earth, Ocean and Atmospheric Sciences, Oregon State University, 104 CEOAS Administration Building, Corvallis, USA; 7Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Roma1, 00143 Rome, Italy 

  • Presentation type: Poster

  • Presentation time: Friday 16:30 - 18:00, Room Poster Hall

  • Poster Board Number: 158

  • Programme No: 3.4.34

  • Theme 3 > Session 4

Abstract

The Ulukışla Caldera (a structure of 2.5 km x 4 km) is part of the Hasandağ Volcanic Complex (Central Anatolia, Turkey) and has been only recently identified as a collapse structure surrounded by several undifferentiated pyroclastic deposits until this study. This study presents a tephrostratigraphic analysis to reconstruct the origin and volcanic evolution of Ulukışla Caldera, examining its volcano-tectonic relationship with the Tuz Gölü Fault Zone (TGFZ). To achieve this, we integrated detailed volcano-stratigraphy, deposit descriptions and distribution, glass chemistry, geochronology, and remote sensing. We identified three major eruption deposits: 1) the ~442 ka pre-caldera Yenipınar Ignimbrite, 2) the ~400 ka Belbaşhanı caldera-forming ignimbrite, and 3) the ~326 ka post-caldera Ulukışla Fall. Since the Ulukışla Caldera is emplaced within (semi-) grabens of the TGFZ, synthetic and antithetic faults have facilitated the formation of the strike-slip/graben caldera. This active fault system may also control the volcanic activity across the entire Hasandağ compound volcano. Recognising this potential volcanic-tectonic relationship is essential for understanding future eruptive behaviour of such volcanic system. Given the Hasandağ's location within this complex tectonic setting, the possibility of a new cone gravitational collapse (e.g., Greater and Lesser Hasandağ) and/or the formation of additional volcanic collapse structures should be included in future volcanic/tectonic hazard assessments. This study has been funded by the PÜSKÜRÜM project (a Marie Skłodowska-Curie Action (grant #101024337) under the European Union's Horizon 2020 research and innovation programme) and the TURVO project (PID2023-147255NB-I00), supported by MICIU/AEI/10.13039/50110001103.