Post-volcanic activities in the Early Miocene Kırka-Phrigian caldera, western Anatolia – caldera basin filling and borate mineralization processes
| Autor: | Martin R. Palmer, Yeşim Yücel-Öztürk, Ioan Seghedi, Cahit Helvaci |
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| Rok vydání: | 2020 |
| Předmět: |
geography
Mineralization (geology) geography.geographical_feature_category 020209 energy Geochemistry chemistry.chemical_element Geology 02 engineering and technology Structural basin 010502 geochemistry & geophysics 01 natural sciences Volcano chemistry 0202 electrical engineering electronic engineering information engineering Caldera Extensional tectonics Boron 0105 earth and related environmental sciences |
| Zdroj: | International Geology Review. 63:1719-1736 |
| ISSN: | 1938-2839 0020-6814 |
| Popis: | The formation of large, economic borate deposits requires a boron-rich source, the means of transporting and concentrating the boron in a restricted environment, and mechanisms for the preservation of the deposit. There are several Miocene basins in western Turkey containing world-class borate reserves, with mineralization present as stratabound deposits in volcano-sedimentary successions. Although it is well-documented that the conditions required to form and preserve large borate deposits are most common in post-collisional tectonic settings (of which western Anatolia is a prime example), recent advances in the understanding of extensional tectonics and volcanism in this region, make it possible to gain fresh insights into their formation. Here, we suggest that formation of one of the largest borate deposits in the world was intimately related to the recently recognized Kırka-Phrigian caldera that lies in the northernmost part of the Miocene Eskişehir–Afyon volcanic field. Following caldera collapse, the basin filled with lacustrine sediments and volcaniclastic deposits with the boron mineralization concentrated in two main sub-basins: Sarıkaya and Göcenoluk. The close spatial and temporal relationship between borate deposition and the vast Early Miocene ignimbrite deposits that surround the caldera (and contain high levels of elements associated with mineralization) strongly suggest that the ignimbrites were the major source of boron. The boron was transported by geothermal fluids and post-volcanic gases that vented into warm water at the base of the caldera-paleolake system and was then concentrated during cycles of sedimentation and evaporation, with most of the mineralization concentrated along a N-S striking fault system. |
| Databáze: | OpenAIRE |
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