Introduction: The Rochechouart impact structure is a deeply eroded, late Triassic impact site located in south-central France [1,2]. Rochechouart impactites comprise five main lithological units from the base of the structure upwards, originally described as follows: unit 1) shocked autochthonous basement rock; unit 2) finely crystalline melt rock; unit 3) red 'welded' breccia/suevite; unit 4) ...

Analogue and computational models principally provide our present understanding of the mechanisms of prograde metamorphism and orogenesis, yet, due to the difficulty of linking prograde age information with the pressure–temperature (P–T) evolution of a rock, these models for the most part remain untested. Here, we describe an approach that allows multiple prograde pressure–temperature–time (P–T...

The variation of permeability with depth can be probed indirectly by various means, including hydrologic models that use geothermal data as constraints and the progress of metamorphic reactions driven by fluid flow. Geothermal and metamorphic data combine to indicate that mean permeability (k) of tectonically active continental crust decreases with depth (z) according to log k ! )14–3.2 log z, ...

We carried out geochemical and mineralogical analyses on fault-zone rocks from the Anko section of the Median Tectonic Line in Nagano Prefecture, Japan, to investigate coseismic physicochemical processes in the fault zone. The latest fault zone in the Anko section contains cataclasite, fault breccia, and fault gouge of granitic composition, and brecciated basic schist. Protoliths of the graniti...

Samples of fault gouge from the San Andreas Fault drill hole (SAFOD), a shale from the North Sea sedimentary basin and schists from metamorphic rocks in the Alps have been analyzed with high energy synchrotron X-rays to determine preferred orientation of mica and clay minerals. The method relies on obtaining 2D diffraction images which are then processed with the crystallographic Rietveld metho...

The Görcsöny Ridge is part of the complicated Variscan metamorphic basement of the SW Tisza plate. It was penetrated by several wells, one of which (Baksa-2) has 1200 m of well core available for petrological examination. Amphibolite samples of this core are of two different sorts: the fi rst group contains biot ite, rutile, and garnet, while the second group contains ilmenite and is free of ga...

Project Description: Theoretical modeling of coupled fluid flow and chemical reactions, involving kinetics, has been employed to understand the differences between equilibrium, steady-state, and non-steady-state behavior of the chemical evolution of open fluid-rock systems. The numerical codes developed in this project treat multi-component, finite-rate reactions combined with advective and dis...

Integrated metamorphic and geochronological data place new constraints on the metamorphic evolution of a Neoproterozoic orogen in east Antarctica. Granulite-facies rocks from a 150 km stretch of the Kemp Land coast reflect peak conditions involving T 870^9908C at P 7 4^10 kbar, with pressure increasing westward towards an Archaean craton. Electron microprobe-derived (ThþU)^Pb monazite ages from...