Results 21 to 30 of about 3,014 (216)
TO THE ONTOGENESIS OF AESCHYNITE IN FELDSPAR VEIN NO. 31 OF THE VISHNEVYE GORY, SOUTH URALS [PDF]
Минералогия, 2022 Small grains of accessory aeschynite in feldspar vein no. 31 of Vishnevye Mountains (South Urals) co-crystallize with late growth zones of feldspar crystals, as well as with ilmenite, titanomagnetite, muscovite, zircon, monazite, thorite, rutile ...
V.A. Popov, I.A. Blinov, V.I. Popova
doaj +1 more source
Reconciling Magma-Ocean Crystallization Models with the present-day Structure of the Earth's mantle [PDF]
Geochemistry Geophysics Geosystems (2017), 18, 7, 2785-2806, 2018 Terrestrial planets are thought to experience episode(s) of large-scale melting early in their history. Fractionation during magma-ocean freezing leads to unstable stratification within the related cumulate layers due to progressive iron enrichment upward, but the effects of incremental cumulate overturns during MO crystallization remain to be explored.
arxiv +1 more source
Metasomatic Replacement of Albite in Nature and Experiments [PDF]
Minerals, 2018 Replacement of albite by sodium-rich, secondary phases is a common phenomenon, observed in different geological settings and commonly attributed to alkaline metasomatism. We investigated growth of nepheline and sodalite on albite in time series experiments between two and 14 days.
Drüppel, Kirsten, Wirth, Richard
openaire +5 more sources
Geochemistry, Geophysics, Geosystems, 2023 Meter‐ to hectometer‐size horizons of carbonate‐bearing talcschists are found along or near the contacts between the different Liguro‐Piemont subduction slices.
Clément Herviou, Guillaume Bonnet
doaj +1 more source
Garnet pyroxenites explain high electrical conductivity in the East African deep lithosphere [PDF]
arXiv, 2021 A large contrast in electrical conductivity has been observed within the lithospheric mantle between the Tanzanian craton and the Mozambique belt at depths > 70 km. Such contrasts are typically attributed to changes in volatiles and/or melt content, with changes in mineralogy deemed insufficient to impact conductivity.
arxiv
Potassium Isotope Compositions of Carbonaceous and Ordinary Chondrites: Implications on the Origin of Volatile Depletion in the Early Solar System [PDF]
, 2020 Solar system materials are variably depleted in moderately volatile elements (MVEs) relative to the proto-solar composition. To address the origin of this MVE depletion, we conducted a systematic study of high-precision K isotopic composition on 16 carbonaceous chondrites (CCs) of types CM1-2, CO3, CV3, CR2, CK4-5 and CH3 and 28 ordinary chondrites ...
arxiv +1 more source
Mineralogical evolution of the northern Bossoroca ophiolite, São Gabriel terrane
Brazilian Journal of Geology, 2020 Mineralogical evolution of ophiolites is significant to understand paleo-oceanic crust and mantle requiring multi-proxy techniques to identify steps in the processes. We studied the Bossoroca ophiolite from the southern Brasiliano Orogen, a prime example
Amanda Juliano Massuda +5 more
doaj +1 more source
Geochemistry, Geophysics, Geosystems, 2023 Talc‐rich rocks are common in exhumed subduction zone terranes and may explain geophysical observations of the subduction zone interface, particularly beneath Guerrero, Mexico, where the Cocos plate subducts horizontally beneath North America and ...
P. C. Lindquist +4 more
doaj +1 more source
Microtextures in the Chelyabinsk impact breccia reveal the history of Phosphorus-Olivine-Assemblages in chondrites [PDF]
, 2020 The geochemistry and textural associations of chondritic phosphate minerals can provide insights into the geological histories of parental asteroids, but the processes governing their formation and deformation remain poorly constrained. Here, we present a quantitative assessment of phosphorus-bearing mineral textures in the three variously-shocked ...
arxiv +1 more source
Volatiles beneath mid-ocean ridges: deep melting, channelised transport, focusing, and metasomatism [PDF]
, 2016 Deep-Earth volatile cycles couple the mantle with near-surface reservoirs. Volatiles are emitted by volcanism and, in particular, from mid-ocean ridges, which are the most prolific source of basaltic volcanism. Estimates of volatile extraction from the asthenosphere beneath ridges typically rely on measurements of undegassed lavas combined with simple ...
arxiv +1 more source