Results 51 to 60 of about 87,697 (345)

Mesozoic-Cenozoic mafic magmatism in Sanandaj-Sirjan Zone, Zagros Orogen (Western Iran): geochemical and isotopic inferences from Middle Jurassic and Late Eocene gabbros [PDF]

open access: yes, 2017
One of the consequences of Neo-Tethys ocean subduction beneath the Central Iranian Micro-continent (CIMC) is the development of rare gabbroic intrusions in the Malayer-Boroujerd Plutonic Complex (MBPC) located in the Sanandaj-Sirjan Zone (SaSZ) of the ...
Deevsalar, Reza   +8 more
core   +1 more source

Exploring wave propagation behaviors in rock: A grain‐based perspective on mineral structures

open access: yesDeep Underground Science and Engineering, EarlyView.
This study investigates wave propagation in rock at the grain scale using a grain‐based model, revealing that mineral elastic modulus significantly influences wave attenuation while grain size and distribution have limited effects. A novel peak particle velocity attenuation prediction model is proposed and validated for grain‐scale wave propagation ...
Zhiyi Liao   +3 more
wiley   +1 more source

A History of Andesite Production via Magma Mixing and Mingling Revealed Microscopically at Ngauruhoe Volcano

open access: yesGeochemistry, Geophysics, Geosystems, 2022
Many andesites erupted at arc volcanoes are the products of magma mixing, and this process could be important in triggering their eruption. Throughout the life of Ngauruhoe volcano (∼2.5 ka), erupted andesites lack macroscopic enclaves or lithological ...
Kate Cocker   +4 more
doaj   +1 more source

Surface hydration‐induced damage in tight oil‐bearing sandy conglomerate reservoirs

open access: yesDeep Underground Science and Engineering, EarlyView.
A series of techniques such as X‐ray diffraction, scanning electron microscopy, energy‐dispersive spectroscopy, conductivity tests, and infrared thermal imaging were used. The key findings are the identification of a two‐stage surface hydration process and the elucidation of the effects of various minerals and elements on the hydration process ...
Anbang Zhao   +5 more
wiley   +1 more source

K-Ar geochronology for hydrothermal K-feldspar within plagioclase in a granitic pluton: constraints on timing and thermal condition for hydrothermal alteration

open access: yesHeliyon, 2021
This study presents the K-Ar geochronology for hydrothermal K-feldspar in plagioclase alteration, including methodology and application to the Toki granite, in central Japan.
Takashi Yuguchi   +3 more
doaj   +1 more source

Evidence for Miocene subduction beneath the Alboran Sea (Western Mediterranean) from 40Ar/39Ar age dating and the geochemistry of volcanic rocks from holes 977A and 978A [PDF]

open access: yes, 1999
Volcanic pebbles in gravels from Sites 977 and 978 in the Alboran Sea (western Mediterranean) were dated (using the 40Ar/ 39Ar single-crystal laser technique) and analyzed for their major- and trace-element compositions (determined by X-ray ...
Duggen, Svend   +4 more
core  

Ages of the Pliocene-Pleistocene Alexandra and Ngatutura Volcanics, western North Island, New Zealand, and some geological implications [PDF]

open access: yes, 1989
The Alexandra and Ngatutura Volcanics are the two southernmost of the Pliocene-Quaternary volcanic fields of western and northern North Island, New Zealand, northwest of Taupo Volcanic Zone TVZ.
Briggs, Roger M.   +3 more
core   +2 more sources

Numerical and experimental study on P‐wave propagation across a rock joint with different orientations

open access: yesDeep Underground Science and Engineering, EarlyView.
Joint orientation significantly affects P‐wave velocity, with the highest velocity at zero‐degree angles, decreasing to 30° as the angle increases. The velocity increases slightly from 30 to 45 degrees but sharply decreases from 45 to 90 degrees. Abstract Determination of the required parameters in different science contexts using the ultrasonic wave ...
Yaghoob Zarei   +4 more
wiley   +1 more source

A micro-analytical approach to partition coefficients in plagioclase and clinopyroxene of basaltic sills in Serra Geral Formation, Paraná Basin, Brazil

open access: yesBrazilian Journal of Geology
: In the present study, detailed micro-analytical data (major and trace elements) in minerals from sills of Serra Geral Formation represents the first attempt to evaluate the partition coefficient of Sc, Ti, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Mo ...
Leonardo Cardoso Renner   +4 more
doaj   +1 more source

Theoretical Models of Decompression-Induced Plagioclase Nucleation and Growth in Hydrated Silica-Rich Melts

open access: yesFrontiers in Earth Science, 2020
Magma ascending from the storage region toward the surface may crystallize small and rapidly-grown crystals, designated as microlites. Upon decompression, the rapid changes of the microlite textures, such as number density and crystal size, directly ...
Edith Mollard   +3 more
doaj   +1 more source

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