New Ar-Ar muscovite and Rb-Sr biotite age data in combination with structural analyses from the Apuseni Mountains provide new constraints on the timing and kinematics of deformation during the Cretaceous. Time-temperature paths from the structurally highest basement nappe of the Apuseni Mountains in combination with sedimentary data indicate exhumation and a position close to the surface after ...

Chromitites associated with strongly altered peridotite from six distinct localities in the Santa Elena ultramafic nappe (Costa Rica) have been investigated for the first time. Santa Elena chromitites commonly display a compositional variation from extremely chromiferous (Cr/(Cr+Al)=0.81) to intermediate and aluminous (Cr/(Cr+Al)=0.54). This composition varies along a continuous trend, correspo...

The Bi’r Umq-Nakasib suture zone, 5-65 km wide and over 600 km long, consists of highly deformed ophiolite nappes and metavolcanic, metasedimentary, and intrusive rocks contained in one of the longest ophiolite-decorated shear zones in the Arabian-Nubian Shield. The rocks originated in a variety of juvenile oceanic environments and include assemblages formed in mid-ocean-ridge, subduction-zone,...

A structural and petrological study of the Late Proterozoic rocks in the Wadi Kid area, Sinai, Egypt indicates the presence of an extensional metamorphic core complex in the northern Arabian–Nubian Shield. Gneissic domes throughout the Arabian–Nubian Shield resemble the core complex of the Wadi Kid area and as a result, they are interpreted as extensional metamorphic core complexes. The presenc...

High levels of hexavalent chromium (Cr(VI)) in groundwater are typically attributed to anthropogenic sources. However, scientific reports over the last decade have demonstrated that relatively high levels of Cr(VI) in groundwater may also be due to natural processes. Cr(VI) is among the most significant groundwater contaminants, since it is a potential carcinogenic compound that is commonly fou...

This study presents the first geochemical, mineralogical and petrological data on mafic ultramafic rocks of Texenna (Lesser Kabylia, north-eastern Algeria) with aim constraining their tectonic setting in context Maghrebide belt. The magmatic-sedimentary complex comprises serpentinite, metabasites (metagabbro, metadolerite metabasalt pillow-lava structures), oceanic metasediments (radiolarite ca...

Microorganisms have been found to etch volcanic glass within volcaniclastic deposits from the Ontong Java Plateau, creating micron-sized tunnels and pits. The fossil record of such bioalteration textures is interpreted to extend back ∼3.5 billion years to include meta-volcanic glass from ophiolites and Precambrian greenstone belts. Bioalteration features within glass clasts from Leg 192 of the ...