Reconstruction of a major caldera-forming eruption from pyroclastic deposit characteristics: Kos Plateau Tuff, eastern Aegean Sea

摘要: The 161 ka explosive eruption of the Kos Plateau Tuff (KPT) ejected a minimum 60 km3 rhyolitic magma, minoramount andesitic magma and incorporated more than 3 vent- conduit-derived lithic debris. source formed caldera south Kos, in Aegean Sea, Greece. Textural lithofacies characteristics KPT units are used to infer dynamics chamber processes, including timing for onset catastrophic collapse. consists six units: (A) phreatoplinian fallout at base; (B, C) stratified pyroclastic-density-current deposits; (D, E) volumetrically dominant, massive, non-welded ignimbrites; (F) deposits ash top. ignimbrite show increases mass, grain size, abundance clasts, runout pyroclastic density currents from source. Ignimbrite formation also corresponds change phreatomagmatic dry activity. imply that mass flux (i.e. intensity) increased climax when major collapse was initiated most voluminous, widespread, lithic-rich coarsest produced, followed by waning period. During climax, deep basement clasts were ejected, along with pumice variably melted vesiculated co-magmatic granitoid chamber. Stratigraphic variations vesicularity crystal content, provide evidence distribution components subsidiary within culminated tapping coarsely crystal-rich magma. Increases during waxing phase is consistent theoretical models moderate-volume eruptions lead Published Elsevier Science B.V.