The concentration of yttrium in pelitic garnets as a function of metamorphic grade has been examined in relation to the distribution of xenotime (YPO4) in samples from New England and British Columbia. Samples with xenotime present only as inclusions in garnet generally possess high-Y cores and concentrations that drop off discontinuously along zoning shoulders of variable width to low-Y outboa...

Bangladesh’s heavy minerals deposits in river systems remain largely unexplored with past research restricted to beach placer along the south-eastern coastline of country. In this study, 64 samples were collected from stable sand bars northern Brahmaputra River. The average total (THM) all sample sites was 10.73 wt%, THM concentrations generally highest at outermost edges and lowest within mid-...

The Sør Rondane Mountains, East Antarctica have been thought to be situated in the collision zone between and West Gondwana during final stage of amalgamation supercontinent. They are therefore recognized as a key region for understanding geological phenomena collisions testing proposed tectonic models. We identified metamorphic rocks with different pressure–temperature–time paths that bounded ...

The metapelitic rocks of the Sikkim Himalayas show an inverted metamorphic sequence (IMS) of the complete Barrovian zones from chlorite to sillimanite + K-feldspar, with the higher grade rocks appearing at progressively higher structural levels. Within the IMS, four groups of major planar structures, S1, S2 and S3 were recognised. The S2 structures are pervasive throughout the Barrovian sequenc...

Ten road cut samples collected from five lithological sections of Lokoja sandstone formation in the Middle Niger basin were investigated using integrated granulometric, petrographic and geochemical analyses. Results of grain size analysis; standard deviation and skewness which ranges from 0.08 to -0.05 and 0.59 to -0.07 respectively suggest very well sorted to moderately well sorted sediments. ...

Abstract As one of the widest terranes exposed in icy Antarctica, Larsemann Hills Prydz Bay belt preserves diverse rock types with a complex metamorphic history and thus is critical to tectono-metamorphic evolution East Antarctica. Garnet-sillimanite-spinel-cordierite-bearing garnet-orthopyroxene-bearing granulites are typical rocks region. Phase equilibrium modelling mineral thermometry based ...

Isotopic data were collected on lower crustal xenoliths to constrain the Mexican lower crust as source material for the mid-Tertiary Sierra Madre Occidental, which is one of the largest silicic volcanic piles known. The xenoliths are predominantly pelitic gneisses and marie orthogneisses that were brought to the surface on the eastern edge of the Sierra Madre Occidental by recent alkalic basalt...

High-grade, migmatitic paragneisses (820°C, 8 kbar peak conditions) of the Valhalla metamorphic core complex experienced the retrograde net transfer reaction (ReNTR): garnet + melt + K-feldspar = sillimanite + biotite + plagioclase during cooling and crystallization of the melt, resulting in an increase in the Fe/(Fe + Mg) of both garnet and biotite at their margins. Diffusion profiles generate...

Muscovite granite (13.8% muscovite, 4.8% normafive corundum) was reacted, with varying percentages of H20, in cold-seal vessels at 2 kbar and in piston-cylinder apparatus between 10 and 35 kbar. The diagrams illustrating melting/crystallization relationships are: P-T sections with both excess H20 and with no H:O added (0.66% H20 in rock); T-X•2o sections at 15 kbar and 25 kbar showing H:O-under...