By Korzhinsky and Schrienemakers, methods, phase relations of Mn-Al-Ca-silicates and other minerals in highly oxidized quartzites and schists of blueschist type metamorphism have been discussed. Because, such rocks were extensively studied in central Shikoku of Japan and in Andros and Evvia islands of Greece, they have been considered as thermodynamic system for discussion. The system contains ...

In the Penninic nappe stack of Western Alps, high- to ultrahigh-pressure metamorphic ophiolites Zermatt-Saas Zone are associated with slivers continental crust. one these slivers, Monte Emilius, overprinting pre-Alpine granulite-facies rocks by subduction-related, Alpine eclogite-facies metamorphism can be studied. Mafic granulites were initially transformed into blueschists. a second step, she...

Deep Slow Slip and Tremors (SSTs) are a combination of transient clusters tectonic tremors slow slip associated with extremely elevated fluid pressures. SSTs thought to reflect transition from viscous brittle plate interface rheology likely exert first-order control on megathrust seismicity. Nevertheless, the deformation mechanisms governing source remain elusive. We herein document occurrence ...

Detailed geological mapping of the Urtier Valley in Western Alps allowed to realize a new map 1:10.000 scale. In mapped area, complete nappe stack axial part Alpine belt crops out. The study focused on two units derived from Piemonte-Ligurian oceanic domain, Broillot and Bardonney units, for which, addition classic petrographic structural considerations, lithostratigraphic approach was applied....

Abstract. Modern-style plate tectonics is characterised by the global operation of cold and deep subduction involving blueschist facies ultrahigh-pressure metamorphism. This has been a common process since Neoproterozoic, but couple studies indicate similar processes were active in Paleoproterozoic, at least on local scale. Particularly conspicuous are extreme conditions ∼ 7 GPa thermal gradien...

We find that in young and warm subducting plates, earthquakes occur just below the Moho. In older plates, earthquakes occur throughout the subducting oceanic crust, as well as the subducting mantle. We document this behavior in several subduction zones where there are independent constraints on earthquake locations and slab structure, specifically for northern and southern Japan, Alaska, and te...

Abstract We report the first occurrence of high-pressure metamorphic aragonite in Precambrian carbonates Jabal Akhdar Dome Oman Mountains (northern Oman). propose a model for both its formation at blueschist facies conditions and subsequent preservation to surface within tectonic framework Late Cretaceous obduction Semail Ophiolite. Aragonite formed temperature ~350 °C pressure ≥0.9 GPa is pres...

High- and ultrahigh-pressure rocks occur in the Austroalpine Nappes a ~400 km long belt from Texel Complex west to Sieggraben Unit east. Garnet growth during pressure increase was dated using Lu-Hf chronometry. The results range between c. 100 90 Ma, indicating short-lived period of subduction. Combined with already published data, our estimates metamorphic conditions indicate field gradient in...

Exhumed fossil subduction zones are archives of the deformation conditions and mechanisms from depths not directly accessible. Microstructural analysis samples exhumed therefrom offers insights into micromechanics processes associated with such as earthquakes, slow aseismic creep. Subducted continental metasediments Tuscan Metamorphic Units Italian Northern Apennines contain a mylonitic foliati...