New eclogite localities and new Ar/Ar ages within the Western Gneiss Region of Norway define three discrete ultrahigh-pressure (UHP) domains that are separated by distinctly lower pressure, eclogite facies rocks. The sizes of the UHP domains range from c. 2500 to 100 km; if the UHP culminations are part of a continuous sheet at depth, the Western Gneiss Region UHP terrane has minimum dimensions...

Iron is an important constituent of kornerupine, (M,Mg,Fe)(Al,Mg,Fe)9(Si,Al,B)5O21(OH,F). We obtained Mössbauer spectra at 300 K on twelve samples with SFe 5 0.30–1.30 atoms per formula unit (apfu) and Fe31/SFe 5 0–0.31; several samples were also run at 77 and 430 K. Models allowing unequivocal refinement of the spectra and determination of site occupancies were developed only when single-cryst...

Common naturally occurring orthosilicates can be grouped into those in which the major non-tetrahedral cations are (1) FeII and/or Mg, plus or minus Al (olivine, pyralspite garnets, staurolite); (2) Al (Al2SiO5 polymorphs), or (3) Zr. Feand Mg-bearing orthosilicates have the weakest bonds between non-tetrahedral cations and structural oxygen (M-O bonds), and zircon the strongest, with Al-O bond...

This study combines field observations, mineral and whole-rock geochemistry, phase equilibrium modeling, U-Pb sensitive high-resolution ion microprobe (SHRIMP) zircon geochronology to investigate sillimanite-bearing felsic migmatites exposed on Ledge Mountain in the central Adirondack Highlands (New York, USA), part of an extensive belt mid-crustal rocks comprising hinterland Mesoproterozoic Gr...

Spiral garnet porphyroblasts are known to record lengthy periods of deformation and metamorphism by preserving single or multiple FIAs (Foliation Intersection Axis) formed normal tectonic shortening directions. Thanks technological advances in X-ray computed micro-tomography (XCMT), can now be readily determined relatively large samples contrast previous methods that require the preparation a s...

This paper investigates the monazite grains from Dibrova rare-earth-thorium-uranium (U-Th-REE) mineral deposit within Azov Megablock of Ukrainian Shield. U-Th-REE mineralization is associated with K-feldspar-quartz metasandstones and metagritstones (hereafter quartzites) pegmatoids. The latter possibly represent products ultrametamorphism/granitization initially sedimentary clastic rocks during...

Heavy minerals have become an essential commodity in modern-day technology. The objective of this study is to examine the current status heavy mineral industry Sri Lanka. present also examines economic viability potential placer deposits, based on geochemical data. Field investigations suggested occurrence as beach-placers, and inland/raised beach deposits along coastline Geochemical results sh...