Results 21 to 30 of about 113 (110)

Raman spectroscopic geobarometer applicable to mantle xenolith

Japanese Magazine of Mineralogical and Petrological Sciences, 2005
Fluid inclusions in mantle-derived minerals can serve as a messenger from the deep Earth. If CO2 is a dominant phase of the fluid, the relationship between intensity ratio and frequency separation of the Fermi diad bands in the Raman spectra of CO2 can be used for determination of density of the inclusions.
YAMAMOTO, Junji, ISHIBASHI, Hidemi, KAWAKAMI, Yoko, KAGI, Hiroyuki   +3 more
openaire   +2 more sources

Origin of Silicic Magmas at Kibblewhite Volcano: Implications for Bimodal Volcanism in the Kermadec Arc

Island Arc, Volume 35, Issue 1, January/December 2026.
ABSTRACT This study investigates the origin of silicic magmas at the Kibblewhite Volcano in the Kermadec arc. Two alternative differentiation pathways are evaluated: fractional crystallization of primary basaltic magmas producing low‐Mg andesites, and fractional crystallization of primary andesitic magmas represented by magnesian andesites.
Yasuhiro Hirai, Yoshihiko Tamura
wiley   +1 more source

Geochemical and structural characterization of the Cruzeiro do Sul Granodiorite: neoproterozoic post-collisional shoshonitic magmatism within transcurrent shear zone, Quitéria region, Southernmost Brazil [PDF]

Geologia USP. Série Científica, 2012
The Cruzeiro do Sul Granodiorite is located in the Eastern portion of the Sul-rio-grandense shield. It forms one ENE-WSW elongate body of approximately 4 km² within a sinistral strike slip shear zone.
Daniel Knijnik, Maria de Fátima Bitencourt, Lauro V. S. Nardi, Viter Magalhães Pinto, Eduardo Fontana   +4 more
doaj  

The Buoyancy of Cratonic Lithospheric Mantle

Geophysical Research Letters, Volume 52, Issue 24, 28 December 2025.
Abstract Cratons are generally thought to be characterized by stable, long‐lived mantle roots. However, recent studies have suggested that the lithospheric mantle may be prone to removal, implying that it may be denser than the asthenosphere. To address these suggestions, we use a global data set of mantle xenoliths to estimate the density structure of
Z. J. Sudholz, A. Copley, K. Priestley
wiley   +1 more source

Calculation and application of clinopyroxene-garnet-plagioclase-quartz geobarometers [PDF]

Contributions to Mineralogy and Petrology, 1988
Recently published thermodynamic and experimental data in a variety of chemical systems have been evaluated to derive Gibbs free energies for hedenbergite and pyrope. These were used to calculate the geobarometric equilibria Hedenbergite+Anorthite=Grossular+Almandine +Quartz: “HD barometer”, Diopside+Anorthite=Grossular+Pyrope+Quartz: “DI barometer ...
Essene, E. J., Moecher, D. P., Anovitz, L. M.   +2 more
openaire   +2 more sources

Fast and Spatially Heterogeneous Cooling Rates at Amphibolite‐Facies Conditions in the Lepontine Alps (Switzerland)

Geochemistry, Geophysics, Geosystems, Volume 26, Issue 11, November 2025.
Abstract The Lepontine dome (European Central Alps) is constituted by basement nappes under Alpine regional Barrovian metamorphism, yet the duration and pattern of its post‐peak amphibolite‐facies cooling remain uncertain. We examine garnet‐rim compositional re‐adjustment and employ inverse multicomponent diffusion modeling to estimate apparent cooling
A. Tagliaferri, E. Moulas, S. M. Schmalholz, F. L. Schenker   +3 more
wiley   +1 more source

Coupling Phase Equilibrium Modelling and Apatite‐in‐Garnet Elastic Barometry to Unravel the P–T Path of the Micaschist Unit From the Zicavo Metamorphic Complex (Corsica, France)

Journal of Metamorphic Geology, Volume 43, Issue 7, Page 681-705, September 2025.
ABSTRACT To gain insights into the pressure–temperature evolution of a scarcely studied portion of the Variscan basement of Corsica in southern Europe, we combined phase equilibrium modelling, Zr‐in‐rutile thermometry and apatite‐in‐garnet elastic barometry. We investigated Grt‐St micaschist rocks containing garnet grains of several millimetres in size
Lorenzo Dulcetta, Xin Zhong, Gabriele Cruciani, Johannes Vrijmoed, Jan Pleuger, Marcello Franceschelli, Timm John   +6 more
wiley   +1 more source

Depth of Ancient Seismicity Along the Woodroffe Thrust (Central Australia): Constraints From Pseudotachylytes in Peraluminous Gneisses

Tectonics, Volume 44, Issue 8, August 2025.
Abstract The Woodroffe Thrust (WT) is a regional‐scale mylonitic shear zone that developed during the Petermann Orogeny (630–520 Ma) in lower to mid‐crustal rocks of the Musgrave Ranges, central Australia. In the upper part the WT hosts the largest volume worldwide of tectonic pseudotachylytes (coseismic quenched frictional melts). The pseudotachylytes
G. Toffol, A. Camacho, N. Mancktelow, G. Pennacchioni   +3 more
wiley   +1 more source

Efficacy of Assessing Magmatic Storage Depth Using Natural Samples, Experiments and Thermodynamic Models: A Case Study From Valles Caldera, NM (USA)

Geochemistry, Geophysics, Geosystems, Volume 26, Issue 7, July 2025.
Abstract Estimates of magmatic storage are typically made using mineral assemblages in natural samples, experiments and thermodynamic models (e.g., MELTS), where each method has limitations. Here, we compare each of these methods to assess their utility in estimating storage conditions for post‐collapse, two‐feldspar high‐silica rhyolites (HSRs ...
Magdalen A. Grismer, Laura E. Waters, Gordon M. Moore, Gabriela A. Farfan   +3 more
wiley   +1 more source

Geobarometers clarify crustal doubling

Eos, Transactions American Geophysical Union, 1981
Two University of Chicago geochemists report what they believe is confirming evidence for the crustal‐doubling theory. The theory, which could explain the great height of the Himalayas, says that parts of several continents were once buried to a depth of 35 km, the entire thickness of the earth's crust.Robert C. Newton, professor of geology, and Dexter
openaire   +1 more source