Results 131 to 140 of about 77,736 (258)

Soil wetting and drying processes influence stone artefact distribution in clay‐rich soils: A case study from Middle Gidley Island in Murujuga, northwest Western Australia

Archaeometry, EarlyView.
Abstract Soils that contain swelling clay minerals (e.g., montmorillonite) expand and contract during wetting and drying, causing movement within the soil profile. This process, known as argilliturbation, can alter artefact distributions, destroy stratigraphy and complicate the interpretation of archaeological deposits.
Caroline Mather, Matthias Leopold, Kaitlin Sullivan, Kane Ditchfield, Tom Horrocks, Luke Gliganic, Emma Beckett, Diana Patalwala, Emielda Yusiharni, Michael Smirk, William Hiscock, Jo McDonald   +11 more
wiley   +1 more source

The Fiery Eyes of a Maenad: Origin Determination of Faceted Garnet Eye Inlays in a Roman Bronze Bust From Southern Tyrol

Archaeometry, EarlyView.
ABSTRACT In 1837, the Tyrolean State Museum Ferdinandeum in Innsbruck, Austria, purchased a Roman bronze statue of a maenad from the 2nd century ce with red garnets as facetted eye inlays found near Brixen, Southern Tyrol. These garnets were investigated using optical microscopy, a portable hand‐held and a stationary micro‐X‐ray fluorescence device, as
H. Albert Gilg, Simon Wagner, Anton Höck, Peter Tropper   +3 more
wiley   +1 more source

Peixe Zircon as a Quality Control Reference Material in U‐Pb Geochronology by LA‐ICP‐MS

Geostandards and Geoanalytical Research, EarlyView.
Key Points Peixe#0 zircon was characterised for U‐Pb geochronology using CA‐ID‐TIMS, SIMS and a long‐term LA‐ICP‐MS data set. The consistent results establish Peixe#0 as a reference material for U‐Pb quality control. Trace element heterogeneity requires careful, CL‐guided spot selection.
Margareth Sugano Navarro, Erica Martini Tonetto, Elson P. Oliveira, Mauricio Ibañez‐Mejia, Cristina Talavera, Neal J. McNaughton, Jacinta Enzweiler, Michael Wiedenbeck   +7 more
wiley   +1 more source

New Magnetite Reference Material for SIMS δ18O Measurements and a Study of Precision and Accuracy Due to Crystal Orientation Effects

Geostandards and Geoanalytical Research, EarlyView.
Key Points A new magnetite reference material (PF21mt) is available for δ18O measurements by SIMS. Reproducibility of measurement results in two laboratories suggest orientation bias of ±2‰ (2s) at 20 keV. Repeatability improves to ±1‰ (2s) when using a 13 keV protocol, suggesting reduced orientation bias. In situ isotope ratio measurements provide the
Michelle Ulrich, Daniela Rubatto, Maria Rosa Scicchitano, Benita Putlitz, Thomas Bovay   +4 more
wiley   +1 more source

Thermal Buffering, Heat Advection and Crustal Thinning in the Ryoke Metamorphic Complex, Yanai, Southwest Japan

Journal of Metamorphic Geology, EarlyView.
ABSTRACT The metamorphic zoning and geothermobarometry of the Ryoke metamorphic complex in the Yanai area, southwest Japan, show that its thermobaric structure was buffered by the dehydration melting of biotite. The temperatures over most of the area covered by the three high‐grade zones (8.5‐ to 19.0‐km depth) are consistent with those of the ...
Takeshi Ikeda, Kazuhiro Miyazaki, Yu Sugawara, Risa Hayashi   +3 more
wiley   +1 more source

Garnet–Clinopyroxene Double‐Layered Coronae in a Metagabbronorite From the High‐Grade Metamorphic Gföhl Unit, Moldanubian Zone

Journal of Metamorphic Geology, EarlyView.
ABSTRACT This study investigates garnet–clinopyroxene double‐layered coronae in a metagabbronorite from the high‐grade metamorphic Gföhl Unit (Bohemian Massif). The coronae formed at the interfaces between relic magmatic orthopyroxene, still preserved in the cores of the coronae, and the plagioclase‐rich rock matrix.
Rene Asenbaum, Tereza Nemeškalová, Martin Racek, Vojtěch Janoušek, Julian Portenkirchner, Rainer Abart   +5 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

Microspherules Formed by Lightning Strikes

Meteoritics &Planetary Science, EarlyView.
Abstract Natural microspherules are formed by high‐temperature processes and are present throughout the geologic record to the present day. We report the discovery of large numbers of microspherules recovered from a rock pavement in the Pilbara region, Western Australia.
M. R. Boyd, M. J. Genge, A. G. Tomkins
wiley   +1 more source

Confirmation of the impact origin of the Late Ordovician Tvären impact structure (southeast Sweden) and emplacement of impactites in a marine setting

Meteoritics &Planetary Science, EarlyView.
Abstract The Tvären structure in southeastern Sweden has been listed as a confirmed marine‐target impact structure for decades. However, to date, no measurements and/or indexed data of planar deformation features in quartz grains from the structure have been published or any other unequivocal evidence of impact.
Katarzyna J. Gajewska, Sanna Alwmark, Mikael Calner, Sylvain Richoz, Jens Ormö, Erik Sturkell, Carl Alwmark   +6 more
wiley   +1 more source

In situ single‐spot Rb/Sr cosmochronology of roedderite in the Ribbeck aubrite (asteroid 2024 BX1)

Meteoritics &Planetary Science, EarlyView.
Abstract The mineralogy and textures of several fragments from the Ribbeck aubrite were analyzed using a combination of scanning electron microscopy, electron microprobe analysis, μRaman spectroscopy, and laser ablation inductively coupled reaction cell mass spectrometry (LA‐ICP‐MS/MS).
Christopher J. Barnes, Aleksander Błasiak, Helge Vinje Birgerheim, Matthias Konrad‐Schmolke, Delia Rösel, Jarosław Majka, Thomas Zack   +6 more
wiley   +1 more source