Results 81 to 90 of about 49,779 (247)

Minerals in Afghanistan : rare-metal deposits [PDF]

, 2007
In Afghanistan rare metals (lithium, caesium, tantalum and niobium) occur in three main deposit types: pegmatites, mineralised springs and playa-lake sediments (Figure 1).
Benham, Antony John, Coats, Stan
core  

Reservoir theory for studying the geochemical evolution of soils [PDF]

, 2010
[1] Linking mineral weathering rates measured in the laboratory to those measured at the landscape scale is problematic. In laboratory studies, collections of minerals are exposed to the same weathering environment over a fixed amount of time. In natural
Almond, Amundson, Anderson, Anderson, Anderson, Baldwin, Birkeland, Blum, Brantley, Brantley, Brown, Burke, Butler, Carson, Chadwick, Dietrich, Dietrich, Dixon, Eriksson, Fernandes, Ferrier, Furbish, Gabet, Gabet, Gabet, Heimsath, Heimsath, Hren, Jenny, Johnson, Johnson, Kaste, Kirkby, Kyungsoo Yoo, Lebedeva, Montgomery, Mudd, Mudd, Mudd, Nikiforoff, Porder, Porder, Prosser, Riebe, Riebe, Rodhe, Roering, Roering, Simon Marius Mudd, Small, Trumbore, Waldbauer, Walker, West, White, Yoo, Yoo, Yoo, Yoo   +58 more
core   +2 more sources

Coesite Discovery in Eclogites Confirms UHP Metamorphism in the Orlica‐Śnieżnik Dome (SW Poland)

Journal of Metamorphic Geology, EarlyView.
ABSTRACT Eclogite lenses are exposed within the orthogneiss‐dominated core of the Orlica‐Śnieżnik Dome in the Sudetes, which forms the northeastern margin of the Bohemian Massif (Variscan Belt of Central Europe). The presence of coesite inclusions in garnet and omphacite confirms that these eclogites underwent ultrahigh‐pressure metamorphism.
Małgorzata Nowak, Lucie Tajčmanová, Marcin Dąbrowski, Iris Buisman, Jacek Szczepański   +4 more
wiley   +1 more source

Decoding Metamorphic Nanodiamonds Formation Through Their Internal Structures

Journal of Metamorphic Geology, EarlyView.
ABSTRACT Metamorphic diamonds offer insights into Earth's evolution, modulating the global carbon cycle through subduction into the mantle and exhumation. However, the formation and internal structure of minute diamonds remain poorly understood. Here, we study the internal structures of diamond‐bearing inclusions from the Eastern Alps using state‐of ...
Tim Sotelšek, Marian Janák, Sašo Šturm, Sorour Semsari Parapari, Nik Gračanin, Kristian Radan, Mehmet Ali Gülgün, Stanislava Milovská, Mirijam Vrabec   +8 more
wiley   +1 more source

Vertical profiling of shock attenuation at the Rochechouart impact structure, France

Meteoritics &Planetary Science, EarlyView.
Abstract Rochechouart, south‐west France, is a complex impact structure. Here, we present the first report of shock barometry of quartz from what are likely parautochthonous basement units at depth, based on samples from the 2017 C.I.R.I.R drilling campaign. The crystallographic orientations of 725 sets of PDFs in 512 quartz grains in samples from four
P. Struzynska, S. Alwmark, C. Alwmark, M. H. Poelchau, P. Lambert   +4 more
wiley   +1 more source

X‐ray computed tomography study of terrestrial analog cores in preparation for Mars sample return

Meteoritics &Planetary Science, EarlyView.
Abstract Mars Sample Return (MSR) is expected to transform planetary science by providing unprecedented access to pristine Martian material. Initial characterization in the sample receiving facility (SRF) will rely on nondestructive techniques such as X‐ray computed tomography (XCT) to document the condition, distribution, and internal features of ...
Sophie Benaroya, Christopher D. K. Herd, David T. Flannery, Nicolas Randazzo   +3 more
wiley   +1 more source

Combining universal‐stage, backscatter electron imaging and electron backscatter diffraction for improved indexing of planar microstructures in quartz and plagioclase

Meteoritics &Planetary Science, EarlyView.
Abstract Quartz and feldspar commonly develop planar microstructures due to shock metamorphism. These are generally investigated and indexed (identifying the crystallographic orientation along which they developed) using a universal stage (U‐stage) on a petrographic microscope.
Lidia Pittarello, Thomas Griffiths, Gerlinde Habler   +2 more
wiley   +1 more source

Near‐Synchronous Cambrian Evolution of the Transbrasiliano‐Kandi‐4°50′ Shear Zone in South America and Africa

Terra Nova, EarlyView.
ABSTRACT The Transbrasiliano‐Kandi‐4°50′ (TK4) shear zone in western Gondwana crosscuts South America and NW Africa for at least 6000 km. Despite its impressive size, the timing of the main episode of dextral ductile shearing is uncertain. We present detailed in situ multi‐mineral geochronology of mylonites from both Brazil and Algeria supporting that ...
F. A. Caxito, B. V. Ribeiro, F. Alkmim, A. Deramchi, C. L. Kirkland   +4 more
wiley   +1 more source

Dating C/S Structures in Syntectonic Granites by In Situ Rb‐Sr Analyses on Muscovite

Terra Nova, EarlyView.
ABSTRACT The interplay of crystallisation, deformation and fluid–rock interactions makes deciphering geochronological information complex in syntectonic granites. In this study, we apply in situ Rb‐Sr analyses to selected samples from the Questembert Variscan syntectonic granite in Western France, which was emplaced along the South Armorican Shear Zone
Philippe Boulvais, Romain Tartèse
wiley   +1 more source

Subcritical Cracking Associated With Subgrain Rotation Recrystallisation in Quartz Inferred From Cathodoluminescence Study

Terra Nova, EarlyView.
ABSTRACT We employed cathodoluminescence (CL) to study deformed quartz phenocrysts from the Cretaceous granite porphyry in SW Japan and observed fracture‐like planar structures appearing as CL‐dark bands. These CL‐dark bands were aligned with low‐angle grain boundaries formed by subgrain rotation recrystallisation.
Takuro Yoshioka, Takamoto Okudaira, Hideo Takagi   +2 more
wiley   +1 more source