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.

/pdf/cenozoic-geodynamic-evolution-of-the-aegean-2w6i0upj7j.pdf

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.

/pdf/arc-magmas-sourced-from-melange-diapirs-in-subduction-zones-3l20i6ie3n.pdf

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

Geology, Magmatism and Structural Evolution of the Yelverton Bay Area, Northern Ellesmere Island, Arctic Canada

The Pearya Shear Zone in the Canadian High Arctic: kinematics and significance [Die Pearya-Scherzone in der kanadischen Hocharktis: Kinematik und Signifikanz]

Between the fjords Dicksonfjorden and Billefjorden in central Spitsbergen, Svalbard’s youngest deposits (Early Givetian to Famennian in age) of the Old Red Sandstone—the Mimerdalen Subgroup—are exposed. They form a narrow outcrop area parallel to the Billefjorden Fault Zone and overlie unconformably the multicoloured sandstones of the Lower Devonian Wood Bay Formation. Stratigraphic rank and subdivision of the succession were changed repeatedly since its first mention in 1910. Based on student work in 1996, as well as regional mapping by the authors in 1993 and 2003, the present work formalizes the stratigraphic framework of the succession. This framework has already been applied in recent geological maps. At the same time it is a continuation of the lithostratigraphic standardization carried out by the Committee on the Stratigraphy of Svalbard (1999), where only post-Devonian rocks were considered. Except for some small-pebble conglomerate layers in the Wood Bay Formation, the upper part of the Mimerdalen Subgroup contains the first coarse-grained deposits in Svalbard’s Old Red since the lowermost Devonian Red Bay Group. Faulting between its formations as well as conglomerate pebbles derived from the Lower Devonian Wood Bay Formation indicate the onset of the Svalbardian Event after the tectonic stability during the deposition of the Wood Bay Formation. The Mimerdalen Subgroup is probably the detrital fill of a small foreland basin derived from erosion during the uplift of the Ny-Friesland Block to the east of the Billefjorden Fault Zone. It was later affected by compressional tectonic movements during the Svalbardian Event. Keywords : Svalbard; geology; stratigraphy; Mimerdalen Subgroup; Devonian; Old Red. To access the supplementary material for this article, please see supplementary files under Article Tools online. (Published: 30 October 2014) Citation: Polar Research 2014, 33 , 19998, http://dx.doi.org/10.3402/polar.v33.19998

https://www.tandfonline.com/doi/pdf/10.3402/polar.v33.19998

Stratigraphy of the uppermost Old Red Sandstone of Svalbard (Mimerdalen Subgroup)

In North Greenland, early Paleozoic metamorphic successions of the north Greenland fold belt are carried along the Kap Cannon Thrust Zone northward over the Late Cretaceous Kap Washington Group and Permo-Carboniferous strata. Ellesmerian deformations and metamorphism occurred prior to ductile deformation in the Kap Cannon mylonites, which developed from shear zones in the hanging wall metamorphics. Heterogeneous shearing affects the Ellesmerian structures, with shear sense indicators suggesting top-to-north displacements in the mylonites. Late Cretaceous mafic dikes and sills record intense ductile deformation in the mylonites and incipient shearing within distinct zones of the hanging wall metamorphics. In the footwall of the mylonite zone, approximately NW directed thrusting with the formation of imbricates in Permo-Carboniferous strata on Lockwood O is related to an oblique ramping beneath and in front of the Kap Cannon Thrust Zone. Since the Kap Washington volcanics are mostly affected by brittle deformation, the onset of thrusting occurred in a deeper crustal level. Condensed ductile deformation within the mylonites, shear zones, and an additional oblique to lateral ramp suggest that shear/strain heating contributed to a local rise in temperature. Continuing displacement led to uplift of the thrust zone bounded block of metamorphic rocks with a final emplacement over the northern volcanics under brittle conditions. According to the age of the magmatic rocks in the footwall, the evolution of the Kap Cannon Thrust Zone probably took place during early Tertiary (Eurekan) times. The regional implications are briefly discussed.

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/1999TC900035

Evolution of the Kap Cannon Thrust Zone (north Greenland)

The tectonic evolution in the Piper Pass area in northern Ellesmere Island (Canadian Arctic) is characterized by the superimposition of two major deformational events: the Paleozoic Ellesmerian Oro...

Karsten Piepjohn

Papers

Geology, Magmatism and Structural Evolution of the Yelverton Bay Area, Northern Ellesmere Island, Arctic Canada

The Pearya Shear Zone in the Canadian High Arctic: kinematics and significance [Die Pearya-Scherzone in der kanadischen Hocharktis: Kinematik und Signifikanz]

Stratigraphy of the uppermost Old Red Sandstone of Svalbard (Mimerdalen Subgroup)

Evolution of the Kap Cannon Thrust Zone (north Greenland)

Deciphering superimposed Ellesmerian and Eurekan deformation, Piper Pass area, northern Ellesmere Island (Nunavut)