Gencalioglu-Kuscu, GFloyd, PA2019-08-012019-08-0120020072-10501099-1034https://dx.doi.org/10.1002/gj.909https://hdl.handle.net/11480/5736Two main volcanic events are distinguished between Saraykent and Akqaki la in the Yozgat province of central Anatolia: (1) early Late Cretaceous-Palaeocene effusive activity, that produced a sequence of intermediate to felsic 'basal lavas'; and (2) marginally later Palaeocene explosive activity that formed a series of covering ignimbrite flows. Due to their close temporal and spatial relation, geochemical comparisons were made between the silicic members of the lavas and ignimbrites, to identify chemical groups and their relative petrogenesis. The basal lavas range from calc-alkaline basaltic andesites to dominant rhyolites. Based on trace element correlations three main geochemical groups were identified: the Akqakisla rhyolites (present as domes); Akcakisla rhyodacites-dacites (lava flows); and Ozan-Saraykent rhyolites (lava flows). Large-ion lithophile elements have been mobile in all the groups, but mainly in the Akqaki la rhyolites. Rare earth element (REE) patterns show marked similarity between the Ozan and Saraykent basal lavas. The Akqaki la dome rhyolites are more fractionated with lower La-N/Yb-N ratios (c. 10), whereas the Akqakisla basal lavas have much higher LaN/YbN ratios (c.30). The chemical coherence and petrographic similarities between the Saraykent and Ozan lavas suggest a single suite related via fractionation. Three geochemical groups were also established for the ignimbrites: Saraykent ignimbrite; Baglica ignimbrite-TokluKizildag crystal tuffs; and Keklikpinar ignimbrite. The ignimbrites, like the basal lavas, display a pronounced depletion in Ba on ORG-normalized plots. Relative to the basal lavas, chondrite-normalized patterns for the ignimbrites are different in displaying negative Eu anomalies that indicate feldspar fractionation. The lack of geochemical overlap or coherence between any of the lava and ignimbrite groups suggests that they represent distinct eruptive events and are not related in ally simple volcanic development and cogenetic sense. Two geochemical features are common to all the volcanic rock groups: (1) the presence of a Nb-Ta anomaly, which is generally accepted as a crustal signature; and (2) the relatively low Y abundances which appear characteristic for the region as a whole. These fundamental features of the local silicic volcanism largely reflect source composition and effects. Copyright (C) 2002 John Wiley Sons, Ltd.eninfo:eu-repo/semantics/closedAccesssilicic volcanicsignimbritesYozgatcentral Anatoliacrustal meltingArticle37214316510.1002/gj.9092-s2.0-0036097697Q2WOS:000175737800005Q2