Lifetimes of rhyolitic magma systems: high temporal resolution magma evolution of the Quaternary Acigöl Complex, Anatolia (Turkey)

• Applicant: Professor Dr. Wolfgang Siebel
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: from 2009 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 108543867

Large-volume, supervolcanic caldera-forming systems are thought to progressively accumulate magma through piecemeal assembly of small magma bodies over timescales ranging between >1 Ma to <100 ka. Their early evolutionary stages are, however, commonly obscured due to explosive destruction and resurfacing of their surroundings. Rhyolite fields such as the Acigöl complex, Central Anatolia, are composed of multiple, individually small centers that form bimodal associations with basaltic monogenetic volcanoes. The ~200 ka longevity of Acigöl, the preponderance of rhyolites, and a basaltic magma shadow zone led previous workers to postulate that it represents a thermally growing system, where smaller magma pulses coalesced into a large, interconnected silicic magma body. We propose to test this hypothesis by establishing a high temporal resolution chronostratigraphic framework for Quaternary volcanism at Acigöl from zircon U-Th disequilibrium and (U-Th)/He dating combined with thermometry and O-Sr-Nd-Pb isotopic data in order to monitor the secular changes in magmatic temperatures and compositions. This directly impacts on the debate on the rates of magma emplacement, the origins of supervolcanic eruptions, and volcanic hazards related to rhyolite fields, and their geothermal potential.

• DFG Programme: Research Grants