Results 61 to 70 of about 3,752 (234)

Petrogenesis of Erg Chech 002 Achondrite and Implications for an Altered Magma Ocean

The Astrophysical Journal
This study conducts mineralogical and chemical investigations on the oldest achondrite, Erg Chech 002 (∼4565 million yr old). This meteorite exhibits a disequilibrium igneous texture characterized by high-Mg-number (atomic Mg/(Mg + Fe ^2 ...
Ziliang Jin, Yishen Zhang, Maitrayee Bose, Sarah Glynn, Frédéric Couffignal   +4 more
doaj   +1 more source

Ruby Xenocrystals in Dacite from Central Mexico

Geofísica Internacional
The occurrence of 1-2 cm in diameter, anhedral xenocrystals of red corundum (ruby) in a dacitic lava- flow from central Mexico -in the state of Hidalgo- has been recorded. Geochemically, this dacite nearly resembles adakitic rock (SiO2=63.73 66.64 wt %), with low alumina contents (Al2O3=14.38 14.93 wt %), sodium (Na2O=3.29 3.57wt %) and titanium ...
Jose Cruz Escamilla Casas, Luis Enrique Ortiz Hernández   +1 more
openaire   +2 more sources

Emplacement Conditions and Alteration of Volcanic Deposits Inferred From Magnetic Properties of the ICDP Eger Drill Site S4 (Bažina Maar), Czechia

Journal of Geophysical Research: Solid Earth, Volume 131, Issue 8, August 2026.
Abstract Titanomagnetite in alkaline maar deposits exhibits variable syn‐ and post‐crystallization alteration linked to wet emplacement and groundwater fluctuations, which remain poorly documented. Magnetic and mineralogical analyses of lapilli, scoria, and basalt from ICDP Eger drill cores S4 and S4b (Bažina maar, western Eger Graben, Czechia) reveal ...
Johanna Berckhan, Agnes Kontny, Katarzyna Dudzisz, Jan Mrlina, Norbert Nowaczyk, Simo Spassov, Franziska D. H. Wilke   +6 more
wiley   +1 more source

Ancient Craton‐Wide Mid‐Lithosphere Discontinuity Controlled by Pargasite Channels

Geophysical Research Letters
The mechanisms governing a commonly observed seismic velocity drop in the cratonic lithosphere, referred to as the mid‐lithospheric discontinuity (MLD), have been widely debated. To identify the composition and seismic structure of MLDs, we have analyzed
Z. J. Sudholz, P. Zhang, C. M. Eakin, G. M. Yaxley, A. L. Jaques, C. Frigo, K. Czarnota   +6 more
doaj   +1 more source

MANTLE TERRANES OF THE SIBERIAN CRATON: THEIR INTERACTION WITH PLUME MELTS BASED ON THERMOBAROMETRY AND GEOCHEMISTRY OF MANTLE XENOCRYSTS

Геодинамика и тектонофизика, 2019
We have studied variations in the structure and composition of minerals from the pipes of the Yakutian kimberlite province (YKP) in different mantle terranes of the Siberian craton.
I. V. Ashchepkov, A. S. Ivanov, S. I. Kostrovitsky, M. A. Vavilov, S. A. Babushkina, N. V. Vladykin, N. S. Tychkov, N. S. Medvedev   +7 more
doaj   +1 more source

Carbonated Inheritance in the Eastern Tibetan Lithospheric Mantle: Petrological Evidences and Geodynamic Implications

Geochemistry, Geophysics, Geosystems, 2020
The timing and mechanism of formation of the Tibet Plateau remain elusive, and even the present‐day structure of the Tibetan lithosphere is hardly resolved, due to conflicting interpretations of the geophysical data.
Fanny Goussin, Nicolas Riel, Carole Cordier, Stéphane Guillot, Philippe Boulvais, Pierrick Roperch, Anne Replumaz, Karel Schulmann, Guillaume Dupont‐Nivet, Filipe Rosas, Zhaojie Guo   +10 more
doaj   +1 more source

Magma Mixing Processes in a Continental Collision Zone: Insights From Mineralogical and Geochemical Constraints

Geochemistry, Geophysics, Geosystems, Volume 27, Issue 7, July 2026.
Abstract Eocene magmatism in southern Tibet records deep geodynamic processes associated with the India‐Asia collision. The Quxu batholith, a representative segment of the Gangdese magmatic belt, hosts widespread mafic microgranular enclaves (MMEs) indicating magma mixing.
Yuanku Meng, Jinghao Zhou, Di Wang, Junling Pei, Qingling Wang, Yu Zhang   +5 more
wiley   +1 more source

Emplacement of Hybrid Continental‐Oceanic Arc Terranes Without Collision: The Devonian Calliope Arc (New England Orogen, Australia)

Tectonics, Volume 45, Issue 7, July 2026.
Abstract The accretion of allochthonous provinces, derived from oceanic plates, has traditionally been considered an important contributor to continental growth. However, increasing evidence shows that some oceanic terranes (e.g., island arcs) are not “exotic,” as suggested by the presence of continental‐derived sedimentary provenance.
Igor V. Gomes, Gideon Rosenbaum, Carlos A. Spier, Jack F. Ward, Luke A. Milan   +4 more
wiley   +1 more source

Coesite-bearing garnet xenocrysts from diatexite in the Nordøyane domain, Western Gneiss Region, Norway: Implications for eclogite-melt interaction at ultra-high pressure [PDF]

Ultra-high-pressure (UHP) metamorphic rocks in the Western Gneiss Region (WGR) of Norway formed in subducted Baltican crust during the Scandian phase of the Caledonian orogeny.
Myrer, Benjamin, Jamieson, Rebecca, Hilchie, Luke M   +2 more
core   +1 more source

Age and isotopic fingerprints of some plutonic rocks in the Wiborg rapakivi granite batholith with special reference to the dark wiborgite of the Ristisaari Island [PDF]

Bulletin of the Geological Society of Finland, 2014
The mid-Proterozoic, locus classicus Wiborg rapakivi granite batholith of southeastern Finland and adjacent Russia comprises a varying, bimodal (silicic-basic) sequence of plutonic, subvolcanic, and volcanic rocks. At the current level of erosion silicic
O.T. Rämö, V. Turkki, I. Mänttäri, A. Heinonen, K. Larjamo, Y. Lahaye   +5 more
doaj   +1 more source