ROLLAND , Y.

This article summarizes the geodynamic evolution of the Caucasus mountain belt from the Paleozoic to Present based on a review of works from Eastern Anatolia, Greater and Lesser Caucasus and Western Iran. The geological history of crystalline basements provides evidence for their derivation from Gondwana, for their drift at 450–350 Ma by...

The Mont-Blanc Massif was intensely deformed during the Alpine orogenesis: in a first stage of prograde underthrusting at c. 30 Ma and in a second stage of uplift and exhumation at 22-11 Ma. Mid-crustal shear zones of 1 mm–50 m size, neighbouring episyenites (quartz-dissolved altered granite) and alpine veins, have localised intense fluid flow,...

We present arguments for an innovative tectonic set-up just prior to the Northern Neotethys obduction event in the NE Anatolian and Lesser Caucasus area. Along the Northern Neotethyan suture (the Ankara–Erzincan–Amasia–Sevan–Akera suture zone), relicts of the northern branch of the Neotethys oceanic domain outcrop as preserved unmetamorphosed...

no abstract

The ophiolites of NE Anatolia and of the Lesser Caucasus (NALC) evidence an obduction over ∼200 km of oceanic lithosphere of Middle Jurassic age (c. 175–165 Ma) along an entire tectonic boundary (>1000 km) at around 90 Ma. The obduction process is characterized by four first order geological constraints:(1) Ophiolites represent remnants of a...

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The reason for obduction, or tectonic transport of oceanic lithosphere onto continents, is investigated by two-dimensional thermo-mechanical numerical modelling based on the geology of the Anatolia–Lesser Caucasus ophiolites. Heating of the oceanic domain and extension induced by far-field plate kinematics appear to be essential for the...

The lithological nature of major interplate boundaries is estimated by a field analysis of a well preserved exhumed subduction channel in the Caucasus Karabakh region. From this field example the subduction channel is a narrow geological object of about 500 m width formed at approximate depth of 10 km along an Andean-type subduction zone. It is...

The ophiolites of Amasia in the northwestern part of the Sevan-Akera suture zone (Lesser Caucasus, NW Armenia) correspond to a well-preserved example of a major obduction of oceanic lithosphere over the South Armenian continental block. Our mapping evidenced a series of (1) un-metamorphosed gabbroic oceanic crust, (2) serpentinites and a...

The ophiolites of Amasia in the northwestern part of the Sevan-Akera suture zone (Lesser Caucasus, NW Armenia) correspond to a well-preserved example of a major obduction of oceanic lithosphere over the South Armenian continental block. Our mapping evidenced a series of (1) un-metamorphosed gabbroic oceanic crust, (2) serpentinites and a...

Museum-grade mica megacrysts of the Phalaborwa phlogopite (ca. 2 Ga) and the Rubikon pegmatite (ca. 0.5 Ga) were screened for intra-grain compositional and chronological heterogeneities by electron probe microanalysis and 40Ar/39Ar dating, respectively. Both micas were known to have Rbsingle bondSr ages indistinguishable from Usingle bondPb...

The expression of pain is altered in people with dementia (PWD), increasing the risk of undertreatment in that population. The objective of this study was to determine whether dementia and the absence of pain assessment in the patients' medical chart reduced the probability of analgesic use in a large sample of nursing home (NH) residents. This...

Estimating the extent and age of the last glacial maxima as well as the chronology of glacial recessions in various environmental contexts is key to source-to-sink studies and paleoclimate reconstructions. The Argentera-Mercantour massif being located at the transition between the Alps and the Mediterranean Sea, its deglaciation chronology can...

The kinematics of the collision in Western Alps are investigated through five balanced cross sections of the whole external domain from the Oisans to the Mont Blanc massif. These cross sections were built using published data for the Jura and subalpine fold-and-thrust belts and new structural and field analysis for the External Crystalline...

Based on new structural and petrological investigations, we present two crustal-scale cross-sections of the Kyrgyz South Tien Shan, and correlations of main faults and units between Kyrgyzstan and China. The overall structure corresponds to a doubly-vergent mountain belt. The Kyrgyz and Chinese areas exhibit identical structural and metamorphic...