Results 51 to 60 of about 2,944 (200)

Investigation of Archean gamma-ray fingerprint: Methodology and tectonic application in central Brazil

Journal of the Geological Survey of Brazil
Gamma-ray spectrometric responses of Archean rocks were studied in order to define a characteristic signature for these rocks. As the half-life of the most frequent Thorium isotope (232Th – half life of 14.05 Ga) is more than 3 times longer relative to ...
Marcus Flavio Nogueira Chiarini, Loiane Gomes de Moraes, Elton Luiz Dantas, Reinhardt Adolfo Fuck, Elias Prado, Raphael Teixeira Corrêa, Jaime Scandolara, Antônio Frasca, Joseneusa Rodrigues, Andre Menezes Saboia   +9 more
doaj   +1 more source

Archean phosphorus liberation induced by iron redox geochemistry

Nature Communications, 2018
Phosphorus is presumed to have been a limiting nutrient in the Archean ocean due to binding to iron oxides. Here, the authors show the heating of iron with phosphate results in the reduction of phosphate to the ion phosphite, which is solubilized and ...
Barry Herschy, Sae Jung Chang, Ruth Blake, Aivo Lepland, Heather Abbott-Lyon, Jacqueline Sampson, Zachary Atlas, Terence P. Kee, Matthew A. Pasek   +8 more
doaj   +1 more source

Hf-Nd Isotopes in Archean Marine Chemical Sediments: Implications for the Geodynamical History of Early Earth and Its Impact on Earliest Marine Habitats

Geosciences, 2018
The Hf-Nd isotope systems are coupled in magmatic systems, but incongruent Hf weathering (‘zircon effect’) of the continental crust leads to a decoupling of the Hf-Nd isotope systems in low-temperature environments during weathering and erosion processes.
Sebastian Viehmann
doaj   +1 more source

Archean geochemistry

Eos, Transactions American Geophysical Union, 1984
A cross section of the Archean crust provided the focus of the 1983 Archean Geochemistry and Early Crustal Genesis Workshop that convened in Ottawa on August 10, 1983. Forty‐six geoscientists registered: 24 from the United States, 16 from Canada, three from Australia, and one each from West Germany, the Peoples' Republic of China, and Zimbabwe.
openaire   +1 more source

Effect of Laboratory Reagents for Cleaning Modern Contamination on the δ15N Integrity of Nitrogen‐Poor Samples

Rapid Communications in Mass Spectrometry, Volume 40, Issue 19, 15 October 2026.
ABSTRACT Rationale Nitrogen isotope values have been widely used for tracing ancient biogeochemical processes, but contaminant‐sensitive materials, such as Precambrian sedimentary rocks, meteorites, or returned extraterrestrial samples, often have low nitrogen levels and are thus vulnerable to modern organic contamination.
Kunmanee Bubphamanee, Andrew Schauer, Roger Buick   +2 more
wiley   +1 more source

Composition and Provenance of Victoria Group Sandstones in Southern North Victoria Land, Antarctica

New Zealand Journal of Geology and Geophysics, Volume 69, Issue 3, September 2026.
Three distinct source areas contributed to sandstones of the Victoria Group within the Transantarctic Basin in southern North Victoria Land. During the Permian, quartzose sandstones were derived from erosion of the local Ross Orogen, likely from an uplifted swell in the area of today's Ross Sea, the Ross High.
Martin Elsner, Robert Schöner, Reinhard Gaupp, Andreas Kronz, Benjamin Bomfleur, Joerg W. Schneider, Lothar G. Viereck   +6 more
wiley   +1 more source

Integrated Multi‐Physics Characterisation of the Northern Kiruna Mining District With Machine‐Learning‐Assisted Interpretation

Geophysical Prospecting, Volume 74, Issue 7, September 2026.
ABSTRACT Integrated earth modelling aims to combine all available geoscientific information to derive one common earth model. However, combining multiple parameters in a meaningful way remains challenging. In this study, we aim to improve mineral exploration workflows through the integration of new magnetotelluric data with other geophysical and ...
Oskar Rydman, Ervin Veress, Maxim Yu. Smirnov, Tobias E. Bauer, Thorkild M. Rasmussen, Niklas Juhojuntti   +5 more
wiley   +1 more source

Geological and isotopic characteristics of granites from the Western Pernambuco-Alagoas Domain: implications for the crustal evolution of the Neoproterozoic Borborema Province

Brazilian Journal of Geology
The Western Pernambuco-Alagoas Domain is a complex tectonic domain of the Southern part of the Neoproterozoic Borborema Province. It borders the Northern margin of São Francisco Craton. U-Pb and Sm-Nd data discussed in this work show that, in the Western
Rodrigo Fabiano da Cruz, Márcio Martins Pimentel, Ana Cláudia de Aguiar Accioly, Joseneusa Brilhante Rodrigues   +3 more
doaj   +1 more source

Development of CCMb: A Low‐Mg Calcite Reference Material for In Situ Measurement of δ18O, δ13C and Selected Trace Elements

Geostandards and Geoanalytical Research, Volume 50, Issue 3, Page 677-700, September 2026.
Key Points Low‐Mg calcite RM developed for in situ microanalysis applications in palaeoclimatology (δ18O, δ13C; Mg, Sr m/m). New data for calcite CRM IAEA‐603 (δ18O, δ13C by SIMS and GS‐IRMS; Mg m/m). No detectable IMF effect of Mg on SIMS δ18O determinations for mass fractions < 3650 μg g‐1.
Andreas T. Hertwig, Maciej G. Śliwiński, Irene Cantarero, Richard A. Stern, Carles Fàbrega, Jakub T. Śliwiński, Thomas Ludwig, František Majs, William Nachlas, John H. Fournelle, Xavier Llovet, Rachelle B. Turnier, David Parcerisa, Anna Travé   +13 more
wiley   +1 more source

Potassium Isotope Evidence for Origin of Archean TTG Rocks From Seawater‐Hydrothermally Altered Oceanic Crust

Geochemistry, Geophysics, Geosystems
Tonalite‐trondhjemite‐granodiorite (TTG) rocks constitute a crucial part of the Archean continental crust, yet their origins remain contentious. It is critical to decipher their source nature and hydration mechanism.
D.‐Y. Xiong, X.‐L. Wang, W. Li, Y.‐F. Zheng, C. R. Anhaeusser, A. Hofmann, D. Wang, J.‐Y. Li   +7 more
doaj   +1 more source