Results 51 to 60 of about 910 (212)

The Transition From Melt Accumulation to Eruption Initiation Recorded by Orthopyroxene Fe‐Mg Diffusion Timescales in Late Holocene Rhyolites, South Sister Volcano, Oregon Cascade Range

Geochemistry, Geophysics, Geosystems, Volume 26, Issue 12, December 2025.
Abstract South Sister volcano, Oregon Cascade Range, USA, has repeatedly erupted rhyolite since ca. 40 ka. The youngest such eruptions are the ca. 2 ka Rock Mesa and Devils Chain rhyolites, erupted several hundred years apart from two multi‐vent complexes separated by 3–6 km. Fe‐Mg interdiffusion models of orthopyroxene rims from both rhyolites produce
Nathan L. Andersen, Annika E. Dechert, Dawn C. S. Ruth, May (Mai) Sas, Julie Chouinard, Josef Dufek   +5 more
wiley   +1 more source

Composition of the Sub‐Cratonic Mantle of the Guiana Shield Inferred From Diamond‐Hosted Inclusions

Geochemistry, Geophysics, Geosystems, 2021
The composition of diamond‐hosted inclusions provides insight into the character of the sub‐cratonic lithosphere of the Guiana Shield. Guyana's Paleoproterozoic diamonds preserve an inclusion suite comprised of forsterite (Fo ∼89.3–91.8), enstatite ...
R. Bassoo, K. S. Befus
doaj   +1 more source

Micro-XANES determination of ferric iron and its application in thermobarometry

Lithos, 2003
Micro-X-ray absorption near-edge structure (XANES) analysis was employed to determine the content of ferric iron in minerals formed in ultrahigh-pressure (UHP) eclogites. It is observed that omphacite and phengite contain significant amounts of Fe3+/Fetot (0.2–0.6), whereas only very low contents are present in garnet (Fe3+/Fetot=0.0–0.03), the latter ...
Schmid, R., Wilke, M., Oberhänsli, R., Janssens, K., Falkenberg, G., Franz, L., Gaab, A.   +6 more
openaire   +5 more sources

Reconstruction of the Talkeetna intraoceanic arc of Alaska through thermobarometry [PDF]

Journal of Geophysical Research: Solid Earth, 2008
The Talkeetna arc is one of two intraoceanic arcs where much of the section from the upper mantle through the volcanic carapace is well exposed. We reconstruct the vertical section of the Talkeetna arc by determining the (re)crystallization pressures at various structural levels. The thermobarometry shows that the tonalites and quartz diorites intruded
Hacker, Bradley R., Mehl, Luc, Kelemen, Peter B., Rioux, Matthew, Behn, Mark D., Luffi, Peter   +5 more
openaire   +2 more sources

3D Petro‐Structural Evolution of the High Pressure‐Low Temperature Phyllite‐Quartzite Nappe Pile in Southern Peloponnese, Greece

Tectonics, Volume 44, Issue 12, December 2025.
Abstract Tectonic underplating of high‐pressure/low‐temperature (HP‐LT) tectonic slices is a key mechanism in crustal growth at convergent margins. Yet, the processes controlling the geometry, depth and sequence of underplating events remain poorly constrained.
Maïlys Bouhot, Armel Menant, Clément Ganino, Samuel Angiboust, Onno Oncken, Laurent Jolivet, Damien Deldicque, Nikolaos Skarpelis, François Orange   +8 more
wiley   +1 more source

A record of magmatic differentiation in plutonic xenoliths from Santorini (Greece)

Volcanica
Plutonic xenoliths from volcanic arcs provide unique insights into transcrustal magmatic systems in subduction zone settings. At Santorini volcano in the Central Aegean Volcanic Arc (Greece), plutonic xenoliths occur throughout a sequence of lavas and ...
Sean Whitley, Ralf Halama, Ralf Gertisser, Thor H. Hansteen, Matthias Frische, Torsten Vennemann   +5 more
doaj   +1 more source

Confronting Episodic vs. Continuous Heat Sources in Long‐Lived Hot Orogens: Insights From Petrochronological Studies in the Nova Venecia Complex, Araçuaí Orogen (SE Brazil)

Journal of Metamorphic Geology, Volume 43, Issue 9, Page 863-890, December 2025.
ABSTRACT Orogenic belts that sustain elevated temperatures at intermediate crustal depths for tens of millions of years are known as hot orogens. The evolution of these hot orogens is largely influenced by thermal maturation, primarily driven by the distribution of heat‐producing elements (HPEs), such as K, Th and U in the overthickened crust.
Lucas R. Schiavetti, Vinicius T. Meira, Sean Mulcahy, Jeffrey D. Vervoort, Peter L. Baker, George L. Luvizotto, Ricardo I. F. Trindade   +6 more
wiley   +1 more source

Review of geothermochronological and thermobarometric techniques for the construction of cooling and exhumation curves or paths for intrusive igneous rocks

Boletín Geológico, 2020
The present study reviews radiometric and thermobarometric techniques used to construct cooling curves or paths to characterize intrusive bodies and to calculate cooling and exhumation rates. To construct these curves or paths, the temperature, time and
Lina María Cetina, Julián Andrés López-Isaza, Mario Andrés Cuéllar-Cárdenas, Anny Julieth Forero-Ortega   +3 more
doaj   +1 more source

P–T CONDITIONS, U/Pb AND 40Ar/39Ar ISOTOPIC AGES OF UHT GRANULITES FROM CAPE KALTYGEI, WESTERN BAIKAL REGION

Геодинамика и тектонофизика, 2021
The study is focused on metapelitic granulites of Cape Kaltygei (Western Baikal region) that contain a diagnostic mineral assemblage of ultrahigh temperature (UHT) metamorphic rocks (orthopyroxene+sillimanite+quartz).
N. I. Volkova, E. I. Mikheev, A. V. Travin, A. G. Vladimirov, A. S. Mekhonoshin, V. V. Khlestov   +5 more
doaj   +1 more source

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