UNLABELLED The search for indisputable traces of life in Archean cherts is of prime importance. However, their great age and metamorphic history pose constraints on the study of molecular biomarkers. We propose a quantitative criterion to document the thermal maturity of organic matter in rocks in general, and Archean rocks in particular. This is definitively required to select the best candida...

The distribution of metamorphic rocks throughout the western European Alps indicates subduction-related metamorphism. However, processes by which high-grade exhume remain disputed. Here, we present two-dimensional petrological–thermomechanical numerical models to investigate facies evolution during orogenesis. We model closure an oceanic basin with exhumed mantle bounded passive margins. To ens...

Graphitization degrees and temperatures of the regional metamorphism in Central Eastern Rhododpes have been determined by values structural parameter d002 (Å) graphite graphite-bear¬ing marbles shists, from Vacha Madan-Erma Reka areas (Madan lithotectonic unit), Ardino–Nedelino area (Startsevo Chernichevo–Boturche (Byala unit). Equations different authors, formulated between 1951 2021, were use...

In central Victoria, inherited zircon in Devonian igneous rocks and detrital metasedimentary country an amphibolite-facies xenolith show that Mesoproterozoic parts of the underlying Selwyn Block cannot be source for all silicic magmas. Zircon inheritance S-type samples reveals significant thermal events at 525–425 Ma 1200–1100 Ma. Both S- I-type have prominent age peaks 420–410 Ma, which record...

Chemical and isotopic changes accompanying seawater-basalt interaction in axial midocean ridge hydrothermal systems are modeled with the aid of chemical equilibria and mass transfer computer programs, incorporating provision for addition and subtraction of a wide-range of reactant and product minerals, as well as cation and oxygen and hydrogen isotopic exchange equilibria. The models involve st...

The research at Mendoke Mountains, Southeast Sulawesi Province, particularly for the study of gold deposits, becomes a new challenge because there is no previous detailed study. This aims to analyze characteristics orogenic which include type and texture quartz veins, alteration hydrothermal mineralization with hosted metamorphic rocks. methods used fieldwork laboratory analysis. veins were ide...

Ophiolites of the Alpine belt derive from closure Mesozoic Tethys Ocean that was interposed between palaeo-Europe and palaeo-Adria continental plates. The orogeny has intensely reworked oceanic rocks into metaophiolites with various metamorphic imprints. In Western Alps, continental-derived units are distributed within two paired bands: An inner band where subduction-related high-pressure (HP) ...

The solubility of uranium (U) in hydrothermal fluid is thought to be controlled by oxidation. In general, mainly transported as U(VI) oxidized fluid, but precipitated U(IV) reduced fluid. However, many geological observations indicate that metamorphic fluids, which are buffered rocks with protoliths such pelite or altered marine basalt, not enriched U. To explore the reason low U we simulated h...