37 research outputs found
First <sup>36</sup> Cl cosmogenic moraine geochronology of the Dinaric mountain karst:VeleĹľ and Crvanj Mountains of Bosnia and Herzegovina
Reconstitution paléogéographique des dynamiques paysagères durant l'Holocène autour de Xanthos et Létôon dans l'ancienne Lycie (Turquie) : premiers résultats
Selon Strabon, Xanthos et Létôon étaient une cité et un sanctuaire majeurs de Lycie à la période hellénistique (ive-iie siècles av. J.-C.). L’archéologue qui étudie ces deux sites ne peut faire l’hypothèse que le paysage dans lequel ils se situent est resté immobile depuis l’arrivée des premiers habitants au viie siècle av. J.-C. Comprendre les sociétés qui ont occupé cet espace, ainsi que leurs relations avec l’environnement, implique de reconstituer les paysages qu’elles ont habités et aménagés, en s’appuyant sur la compréhension des conditions environnementales et des dynamiques géomorphologiques qui s’y sont exercées. Dans cet article, les premiers résultats issus de l’analyse de séquences carottées et de profils géophysiques sont interprétés et confrontés aux sources historiques, archéologiques et littéraires, et une première reconstitution de l’évolution des paysages est proposée. Les enregistrements sédimentaires indiquent qu’une baie marine a été progressivement fermée par le développement d’une flèche littorale à l’arrière de laquelle s’établissait un système lagunaire. C’est dans ce contexte paysager que se sont développés les deux sites. Face au Létôon un ancien chenal a été identifié, qui permettait peut-être une relation directe, par le fleuve, du sanctuaire avec la mer en aval, et avec la cité de Xanthos en amont. L’étude de la morphologie de la vallée dans son ensemble révèle une forte mobilité des paysages, qui a contraint les hommes à choisir des sites protégés dans des lieux stratégiques pour y installer leurs cités, leurs sanctuaires et leurs voies de communication. La mobilité des paysages a aussi été exploitée de manière symbolique : installé dans un environnement hostile de marécages en plaine alluviale, le sanctuaire de Létôon se pose comme un défi aux lois de la nature
Permafrost conditions in the Mediterranean region since the Last Glaciation.
Cold-climate geomorphological processes today in the Mediterranean region are only distributed in the highest mountain environments. However, climate condition prevailing during the Late Pleistocene and Holocene have conditioned significant spatio-temporal variations of the glacial and periglacial domain in these mountains, including permafrost. In this communication we examine permafrost condition in the Mediterranean region taking into account five periods: Last Glaciation, deglaciation, Holocene, Little Ice Age (LIA) and present-day. The distribution of currently inactive permafrost-derived landforms and sedimentary records indicates that the permafrost elevation during the Last Glaciation was ca. 1000 m lower than present. Permafrost was also widespread in non-glaciated slopes above the snowline forming rock glaciers and block streams, as well as in relatively flat summit areas where meter-sized stone circles developed. As in most areas of the Northern Hemisphere, the deglaciation in the Mediterranean region started ca. 19-20 ka. The exposed terrain by retreating glaciers was affected by paraglacial dynamics and intense periglacial processes, mostly associated with permafrost condition. Many rock glaciers, protalus lobes and block streams formed in these recently deglaciated environments, becoming gradually inactive as temperatures rose during the Bølling-Allerød. Following the Younger Dryas glacial advance, the last massive deglaciation in Mediterranean mountains took place during the Early Holocene together with a progressive shift of the periglacial belt to higher elevations. It is unlikely that widespread permafrost have existed in Mediterranean mountains during the Holocene, except in the highest massifs exceeding 2500-3000 m. The colder climate prevailing during the LIA favoured a minor glacial advance and the spatial expansion of permafrost, with the development of new protalus lobes and rock glaciers in the highest massifs. Finally, the warming started during the second half of the 19th century has led to glacial retreat and/or complete melting, increased paraglacial activity, migration of periglacial processes to the highest lands and degradation of alpine permafrost along with geoecological changes
Quaternary glacial history of the Mediterranean mountains
Glacial and periglacial landforms are widespread in the mountains of the Mediterranean region. The evidence for glacial and periglacial activity has been studied for over 120 years and it is possible to identify three phases of development in this area of research. First, a pioneer phase characterized by initial descriptive observations of glacial landforms; second, a mapping phase whereby the detailed distribution of glacial landforms and sediments have been depicted on geomorphological maps; and, third, an advanced phase characterized by detailed understanding of the geochronology of glacial sequences using radiometric dating alongside detailed sedimentological and stratigraphical analyses. It is only relatively recently that studies of glaciated mountain terrains in the Mediterranean region have reached an advanced phase and it is now clear from radiometric dating programmes that the Mediterranean mountains have been glaciated during multiple glacial cycles. The most extensive phases of glaciation appear to have occurred during the Middle Pleistocene. This represents a major shift from earlier work whereby many glacial sequences were assumed to have formed during the last cold stage. Glacial and periglacial deposits from multiple Quaternary cold stages constitute a valuable palaeoclimatic record. This is especially so in the Mediterranean mountains, since mountain glaciers in this latitudinal zone would have been particularly sensitive to changes in the global climate system. © 2006 Edward Arnold (Publishers) Ltd
Chlorine degassing constrained by cosmogenic 36Cl and radiocarbon dating of early Holocene rhyodacitic lava domes on Erciyes stratovolcano, central Turkey
The Erciyes stratovolcano in central Turkey has several young rhyodacite lava domes that show evidence of clear exposure histories but have hitherto unknown ages. We collected 27 surface samples from three volcanic domes namely Karagüllü Perikartın and Dikkartın for cosmogenic 36Cl dating. The Perikartın eruption generated a pyroclastic flow, which buried trees that were converted to charcoal. The radiocarbon (14C) dating yielded an average age of 9728 ± 110 cal. years B.P. (calibrated using Calib 7.1). We analyzed the cosmogenic 36Cl ages, however, were found that they were probably affected by Cl degassing of the magma. Our study suggests that the radiocarbon age indeed lies between the 0% Cl degassing (6.8 ± 0.5 ka, under nucleogenic 36Cl equilibrium) and the 100% degassing conditions (9.9 ± 0.6 ka, under nucleogenic 36Cl disequilibrium), which implies a partial Cl degassing (93%) during the eruption. This value is somewhat higher than earlier estimates and the difference may result from the miscalculated nucleogenic and/or low-energy neutron production of 36Cl, uncertainties arising from the corrections due to hydrogen-rich cover (i.e., snow) of lava surfaces or due to unconsidered geological complications. Our findings provide a novel approach to estimate the Cl degassing on young lavas and deliver a new evidence of the Holocene volcano-chronology of the central Anatolia. © 2018 Elsevier B.V.This work is supported by the Scientific and Technological Research Council of Turkey (TUBİTAK, project numbers 101Y002 and 107Y069 ) granted to A.Ç. and the US National Science Foundation (Grant 0115298 ) granted to M.Z. We thank A. M. Celal Şengör (İstanbul Technical University) for translating the ancient Greek to English from Strabo's book of Geography. We thank to reviewers Fred M. Phillips and Silke Mechernich and editor Heidy Mader for their help that substantially improved this paper. Appendix
Facies architecture and depositional evolution of alluvial fan to fan-delta complexes in the tectonically active Miocene Köprüçay Basin, Isparta anlge, Turkey
International audienc
Qualification design and sanitation for pure drinkable water: A project study
Drinking water quality management has been a key element of primary prevention and control of waterborne diseases for a long time. This chapter is based on the EU Project "Implementation of ECVET for Qualification Design in Drinking Water Treatment Plants and Sanitation for Pure Drinkable Water- PUREH2O" that contributes to the recognition and transparency of qualifications at the EU level and provides an innovative model for competencies for the potable water sector. The main dilemma that PURE-H2O intends to tackle is the lack of mutual recognition of qualification that is often impaired by national restrictions by applying EUROPASS, European/National Qualification Framework (EQF/.NQF), and the European Credit System for Vocational Education and Training (ECVET) instruments. The aim of the project is to enhance the quality and performance of VET system improving education in drinking water supply and development. This project could also be achieved through promoting creativity, innovation, and transfer of EQF/NQF principles in education of the main target group in the sector, © 2018, IGI Global