The Aegean region is a concentrate of the main geodynamic processes that shaped the Mediterranean region: oceanic and continental subduction, mountain building, high-pressure and low-temperature metamorphism, backarc extension, post-orogenic collapse, metamorphic core complexes, gneiss domes are the ingredients of a complex evolution that started at the end of the Cretaceous with the closure of the Tethyan ocean along the Vardar suture zone. Using available plate kinematic, geophysical, petrological and structural data, we present a synthetic tectonic map of the whole region encompassing the Balkans, Western Turkey, the Aegean Sea, the Hellenic Arc, the Mediterranean Ridge and continental Greece and we build a lithospheric-scale N-S cross-section from Crete to the Rhodope massif. We then describe the tectonic evolution of this cross-section with a series of reconstructions from ~70 Ma to the Present. We follow on the hypothesis that a single subduction has been active throughout most of the Mesozoic and the entire Cenozoic, and we show that the geological record is compatible with this hypothesis. The reconstructions show that continental subduction (Apulian and Pelagonian continental blocks) did not induce slab break-off in this case. Using this evolution, we discuss the mechanisms leading to the exhumation of metamorphic rocks and the subsequent formation of extensional metamorphic domes in the backarc region during slab retreat. The tectonic histories of the two regions showing large-scale extension, the Rhodope and the Cyclades are then compared. The respective contributions to slab retreat, post-orogenic extension and lower crust partial melting of changes in kinematic boundary conditions and in nature of subducting material, from continental to oceanic, are discussed.

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Cenozoic geodynamic evolution of the Aegean

A full-plate global reconstruction of the Neoproterozoic

http://perso.numericable.com/laetitia.le.pourhiet/publications_files/Jolivetetal2012.pdf

Aegean tectonics: Strain localisation, slab tearing and trench retreat

At subduction zones, crustal material enters the mantle. Some of this material, however, is returned to the overriding plate through volcanic and plutonic activity. Magmas erupted above subduction zones show a characteristic range of compositions that reflect mixing in the magma source region between three components: hydrous fluids derived from the subducted oceanic crust, components of the thin veneer of subducted sediments and peridotite mantle rocks. The mechanism for mixing and transport of these components has been enigmatic. A combination of results from the fields of petrology, numerical modelling, geophysics and geochemistry suggests a two-step process. First, intensely mixed metamorphic rock formations—melanges—form along the interface between the subducted slab and the mantle. As the melange contains the characteristic three-component geochemical pattern of subduction-zone magmas, we suggest that melange formation provides the physical mixing process. Then, blobs of low-density melange material—diapirs—rise buoyantly from the surface of the subducting slab and transport the well-mixed melange material into the mantle beneath the volcanoes. Magma erupted at subduction-zone volcanoes contains mantle rocks and a mixture of fluids and sediments derived from the subducted slab. A synthesis of work over past years provides an integrated physico-chemical framework for subduction zones with mixing at the slab–mantle interface and transport towards the surface volcanoes by buoyant diapirs.

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Arc magmas sourced from melange diapirs in subduction zones

https://cyberleninka.org/article/n/651108.pdf

Application of organic petrography in North American shale petroleum systems: A review

Structural evidence for sinistral displacement on the Wegener Fault in southern Nares Strait, Arctic Canada

Regional geology, northeast Ellesmere Island

Eurekan faults on northern Ellesmere Island, Arctic Canada: from Cenozoic strike-slip tectonics to recent seismicity

This is the peer reviewed version of the following article: Dallmann, W. & Piepjohn, K. (2018). Comment on “The Keisarhjelmen detachment records Silurian–Devonian extensional collapse in Northern Svalbard”. Terra Nova. 30(4), 319-321, which has been published in final form at https://doi.org/10.1111/ter.12335 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

/pdf/comment-on-the-keisarhjelmen-detachment-records-silurian-3kw0dd1xbp.pdf

Comment on“The Keisarhjelmen detachment records Silurian–Devonian extensional collapse in Northern Svalbard”

The Erdmannshohle is located at the NE margin of the Dinkelberg plateau in SW Germany With a length of 2315 m, it is the longest cave in the deep open karst area near the village of Hasel Three main cave levels developed in moderately SW-dipping, thinly bedded and fractured limestones of the Upper Muschelkalk (Triassic) The youngest cave level containing the cave stream is still active Eighteen samples for U/Th dating were taken from the oldest and the intermediate cave levels At the oldest cave level, the ages range from 162 to 110 ka, indicating speleothem growth starting in the middle Beringen Glaciation and terminating at the end of the Eem Interglacial At the intermediate cave level, the ages range from 100 to 12 ka, ie early Birrfeld Glaciation to Younger Dryas Stadial The age dating shows that speleothem growth did not cease completely during long periods of harsh climate conditions during the Beringen and Birrfeld glaciations and that permafrost terminating speleogenesis and speleothem growth was thus probably established only temporarily over relatively short periods A conceptual model for the Middle Pleistocene to Holocene development of the Erdmannshohle is presented within the framework of modern Quaternary lithostratigraphy This model facilitates a first correlation of the cave evolution with the Middle to Late Pleistocene depositional record in the Mohlinerfeld, which is a key area for modern Quaternary lithostratigraphy in Switzerland and Southern Germany Thus, speleological and Quaternary research, both based on a regional scale data compilation, complement one another with respect to the timing of events and the landscape evolution during the Quaternary and Late Neogene

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Karsten Piepjohn

Papers

Structural evidence for sinistral displacement on the Wegener Fault in southern Nares Strait, Arctic Canada

Regional geology, northeast Ellesmere Island

Eurekan faults on northern Ellesmere Island, Arctic Canada: from Cenozoic strike-slip tectonics to recent seismicity

Comment on“The Keisarhjelmen detachment records Silurian–Devonian extensional collapse in Northern Svalbard”

The Erdmannshöhle near Hasel, SW Germany: karst environment and cave evolution