کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4712697 1638304 2016 18 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Reconstructing the evolution of an eroded Miocene caldera volcano (Yamanlar volcano, İzmir, Turkey)
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Reconstructing the evolution of an eroded Miocene caldera volcano (Yamanlar volcano, İzmir, Turkey)
چکیده انگلیسی


• Yamanlar volcano in western Turkey is documented as a caldera volcano for the first time.
• The caldera seems to have experienced post-collapse unrest culminating in eruptive activity.
• Downthrown displacement along the ring-fault system amounts up to 90 m.
• Peperitic textures indicate a coeval deposition of lacustrine sedimentation and initiation of volcanism.

The Miocene Yamanlar composite volcano is located in the central part of a shear zone in western Turkey. The volcano's deeply-eroded interior provides excellent three-dimensional exposure of a faulted caldera-floor and caldera-fill rocks as well as surrounding extracaldera ignimbrites. We present a much-revised stratigraphy and geological map of Yamanlar in order to quantify the evolutionary stages of the volcano. The Yamanlar volcanic cone was composed of > 800 m of basaltic-andesite to andesite lavas and lava domes. The volcano underwent at least one phase of caldera formation associated with an explosive eruption that deposited an ignimbrite sheet within and outside the caldera. Lithofacies architecture analysis is applied to the proximal and medial exposures of the Early-Middle Yamanlar Formation, which occurs outside of the caldera. Field evidence of the succession indicates a caldera-forming eruption. Our results indicate that the formation of the Yamanlar caldera resulted from one major catastrophic eruption that generated several sustained pyroclastic density currents (PDCs) subdivided by fall deposits with sharp contacts. The ignimbrite sheet is composed of four flow units. The presence of numerous coarse-grained lithic-rich horizons within the ignimbrite sheet is consistent with caldera subsidence. Post-caldera volcanism is indicated by intrusions and lava domes erupted along the inferred caldera-bounding faults, some of which record ~ 90 m of displacement. Widespread, coarse-grained breccias that overlie the ignimbrite sheet are interpreted as debris avalanche deposits resulting from gravitational failure of the flanks of the volcano or the caldera wall during or after caldera subsidence.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Volcanology and Geothermal Research - Volume 318, 15 May 2016, Pages 1–18
نویسندگان
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