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Le volcanisme calco-alcahn d'Anatohe centrale est à l'origine de changements rapides et conséquents des environnements quaternaires. Les deux grands complexes rhyohtiques du Gollu Dag et d'Acigol intègrent des caldeiras, de nombreuses pyroclastites et des extrusions laviques s'intercalant avec des formations détritiques variées. Le premier a fonctionné du Pleistocene inférieur jusqu'au Pleistocene moyen. Le second s'étend de la fin du Pleistocene moyen au Pleistocene supérieur.Les données présentées permettent de suivre l'évolution rapide de ces complexes, de définir la caldeira du Gollu Dag et de redéfi ni r celle d'Acigol. Chacun de ces complexes à fonctionné en trois phases, pré-, syn-et post-caldeira. Ces phases sont responsables de l'éruption de volumes très différents de magma et de modifications d'ampleur variable des environnements. Les phases syn-caldeira sont responsables des changements les plus importants et les plus rapides. Elles se traduisent par la mise en place de grands volumes de pyroclastites et une modification fondamentale des reliefs et du réseau hydrographique préexistant. Les phases post-caldeira induisent des changements plus modestes, marqués par 1' extrusion répétée de dômes dont nous décrivons un modèle de mise en place original associant phréatomagmatisme, intrusion de dykes annulaires d'obsidienne, activité peléenne, et extrusion rhyohtique. Ces dykes d'obsidienne sont à l'origine d'une importante fréquentation de la région par les sociétés humaines au cours du Paléolithique et du Néolithique. La moindre ampleur des volumes émis et l'étalement des éruptions dans le temps permet l' interstratification des pyroclastites avec des formations alluviales et colluviales pleistocenes. Cette évolution définit des séquences variées où s'intercalent des téphra-repères et des industries paléolithiques. Leur étude permet d'analyser les différents facteurs contrôlant leur mise en place et de les resituer dans un cadre téphrostratigraphique largement inédit.

The geology and especially the magmatic rocks of Gökçeada, which is the biggest island of Turkey and located at 20 km's west of Biga Peninsula, constitute the subject of this study. Late Ediacaran/Early Paleozoic aged Çamlıca metamorphics which crop out with a tectonic uplift in a narrow area in northwest of Gökçeada are the oldest rocks of the island. Early Eocene aged Karaağaç Formation which is formed by submarine fan deposits unconformably overlies Çamlıca metamorphics. As for the Dağiçitepe volcanic member which is formed by rhyolitic lavas, tuff and tuffites emplaced into Karaağaç Formation cutting Çamlıca metamorphics is the oldest volcanic unit of the study area. On Karaağaç Formation, Koyunbaba Formation has unconformably been deposited which consists of Middle Eocene shallow marine sediments. Then it has conformably been overlain by Soğucak Formation which consists of SE-NW extending reefal limestone. Middle-Upper Eocene aged Ceylan Formation which conformably overlies the Soğucak Formation and the early Oligocene aged Mezardere Formation which conformably overlies Ceylan Formation have been deposited due to turbiditic currents in deep marine environment. Late Eocene(?) -Oligocene aged subvolcanics which cut Mesozoic and Eocene units and emplaced into Eocene aged sedimentary units in the form of crypto dome and dome form the recent rigid topography of the study area and are the second magmatic phase called the "Gökçeada Domes". Diorite-monzonites porphyry which crystallized in lower zones of subvolcanics on the other hand constitutes Mutludere intrusion. In eastern and southern parts of Gökçeada, Late Oligocene Gökçeada ignimbrites are located which are observed in the form of pumice flows on Mezardere Formation. These ignimbrites are then overlain by Early Miocene aged Kesmekaya volcanics which are formed by blocky ash flows. Middle Miocene aged Eşelek volcanics consisting of lava and pyroclastics with composition basaltic andesite and andesite are observed on a large area in east of Gökçeada. Upper Miocene aged Çanakkale Formation which is generally formed by the intercalation of poor consolidated conglomerate, sandstone, siltstone and marl crops out in narrow regions at east, southeast and south of Gökçeada. Quaternary alluvial deposits and debris composed of loose, unconsolidated sand, silt and other sediments unconformably overlie all previous units and complete the succession. Main tectonic structures of Gökçeada are formed by right lateral oblique faults which developed in Neo-tectonic period.

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This research proposes a suite of volcanic events that took part in the edification of the double-peaked Hasandağ stratovolcano in southern Cappadocia. Inter-correlations of sections dispatched along geographic transects across the volcano evidence continuities/discontinuities and stratigraphic relationships using key layers identified through this process which is, later, framed by a radiometric dating control of some of these formations. The main goal is to provide some chronological markers of the geomorphological evolution of the volcano. The stratigraphy, lithology and facies, the landform definitions and new dates provide information about eruption types and their role in shaping the morphologies of the volcano through time. Recent ages from literature and seven new K/Ar dates contribute in enriching the story of the volcanic activity that built the Hasandağ stratovolcano landforms. The part of the story exposed in this article starts mainly c. 700/650 ka ago with the construction of a Mid-Pleistocene volcano. Later, between 220 and 120 ka ago, main events occurred in the NE part of the volcano. After an initial Plinian eruption, a caldera collapse is recorded by pumice flows. Close to the emission point, a small collapse structure is today filled with a much younger dacite flow. After the Plinian eruption, the partial destruction of a volcano caused one or two avalanches containing several meters-thick distinct blocks that flew north c. 16-18 km over the roof of the Cappadocian Miocene ignimbrites. Remains of the destructed volcano flanks are not visible. Either they are buried below younger lava flows forming the Küçük Hasandağ cone, or a seism in the Tuz Gölü Fault Zone during the avalanche may have resulted in an explosion. This event was followed by extrusion of rhyolitic domes positioned on the caldera rim, emitting pumice falls now filling-in the Güvercin valley stream down to Ihlara village. During Late Pleistocene emission of andesite and dacite flows and domes, accompanied by several pyroclastic flows formed today's terminal cones of the stratovolcano.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.