Results 1 to 10 of about 7,282 (216)

Reaffirming the Consistency of the Original Stock of NBS 19 Limestone and Its Byproduct With Finer Grain Size for δ13C and δ18O Calibrations—Both Distributed Internationally [PDF]

Rapid Communications in Mass Spectrometry, Volume 40, Issue 18, 30 September 2026.
ABSTRACT Rationale Approximately 3–4 kg of NBS 19 limestone, prepared in 1982 by the U.S. Geological Survey (USGS), serves as a primary reference for the carbon isotope scales VPDB and VPDB‐LSVEC and the oxygen isotope scale VPDB. Its consensus values are +1.95‰ for δ13C and −2.2‰ for δ18O measurements.
Haiping Qi, Tyler B. Coplen, Lauren T. Reid, Stanley J. Mroczkowski   +3 more
wiley   +2 more sources

Carbonatite Melts and Electrical Conductivity in the Asthenosphere [PDF]

Science, 2008
Electrically conductive regions in Earth's mantle have been interpreted to reflect the presence of either silicate melt or water dissolved in olivine. On the basis of laboratory measurements, we show that molten carbonates have electrical conductivities that are three orders of magnitude higher than those of molten silicate and five orders of magnitude
Gaillard, Fabrice, Malki, Mohammed, Iacono-Marziano, Giada, Pichavant, Michel, Scaillet, Bruno   +4 more
openaire   +3 more sources

Geochemical studies and economic perspective of light rare earth element (LREE) enriched carbonatite from Khaderpet, Eastern Dharwar Craton

Discover Geoscience
An account of petrographic features, geochemical character, enriched light rare earth elements (LREEs), and stable isotope (C–O) concentrations in carbonatite occurring in association with lamprophyre clan rock (LCR) from Khaderpet is presented here. The
Pothuri Ramesh Chandra Phani, Prabir Sengupta   +1 more
doaj   +1 more source

Depositional History of the Namibian Mud Belt Reveals Late Holocene Weakening of the Benguela Coastal Current

Geochemistry, Geophysics, Geosystems, Volume 27, Issue 9, September 2026.
Abstract We investigate late Holocene changes in the northern Benguela Upwelling System using a multi‐proxy approach on shallow shelf deposits from the Namibian mud belt. Three sediment cores characterized by organic carbon‐rich, anoxic, and partly gas‐bearing sediments were retrieved along a sampling transect at 23°S in August 2019.
Michael Kossack, Chloe H. Anderson, Nikolas Römer‐Stange, Jürgen Titschack, Florian Scholz, Matthias Zabel   +5 more
wiley   +1 more source

MINERALOGY AND ZIRCON AGE OF CARBONATITES OF THE SREDNYAYA ZIMA COMPLEX (EASTERN SAYAN)

Геодинамика и тектонофизика
The Srednyaya Zima alkaline-ultramafic carbonatite complex is located in the Eastern Sayan and is a part of the area of manifestation of Neoproterozoic rare-metal alkaline-carbonatite magmatism along the southern and southeastern margins of the Siberian ...
I. R. Prokopyev, A. G. Doroshkevich, M. D. Varchenko, D. V. Semenova, I. A. Izbrodin, M. N. Kruk   +5 more
doaj   +1 more source

Kamafugite Magma Pathways and Lava‐Flow Paleotopography From Three‐Dimensional Audiomagnetotelluric Imaging Constrained by Borehole Data

Earth and Space Science, Volume 13, Issue 8, August 2026.
Abstract An audiomagnetotelluric (AMT) survey was conducted within the Alto Paranaíba Igneous Province, southeastern Brazil, to delineate shallow occurrences of kamafugite, a rare ultrapotassic volcanic rock worldwide. A dense grid of AMT stations was deployed, allowing the construction of a high‐resolution 3D electrical resistivity model ...
Lucca M. Franco, Emanuele F. La Terra, Liliane P. Panetto, Adevilson O. Alves, Miguel A. Tupinambá, Sergio L. Fontes, Emin U. Ulugergerli   +6 more
wiley   +1 more source

Carbonatites of India [PDF]

Journal of the Geological Society of India, 2019
ABSTRACT Based on the field relations, associated rock types and age, the carbonatite-alkaline rock complexes of India, that are spatially related to deep main faults, rifts and shear zones, have been classified in to two major groups, namely: 1. Middle – late Cretaceous, subvolcanic – volcanic complexes (Amba Dongar, Siriwasan, Swangkre,
openaire   +1 more source

U-Pb dating of niobium minerals from the pyrochlore group (Ilmeny-Vishnevogorsky carbonatite-miaskite complex, South Urals)

Литосфера, 2020
The article covers the U-Pb dating of minerals belonging to the pyrochlore group from the rare-metal ore deposits of Ilmeny-Vishnevogorsky carbonatite-miaskite complex (South Urals). Individual pyrochlore crystals were dated through a new technique of in-
I. L. Nedosekova, V. A. Koroteev, B. V. Belyatsky, V. V. Sharygin, Е. N. Lepechinа, S. V. Pribavkin   +5 more
doaj  

Does a carbonatite deposit influence its surrounding ecosystem?

FACETS, 2019
Carbonatites are unusual alkaline rocks with diverse compositions. Although previous work has characterized the effects these rocks have on soils and plants, little is known about their impacts on local ecosystems.
James M.C. Jones, Elizabeth A. Webb, Michael D.J. Lynch, Trevor C. Charles, Pedro M. Antunes, Frédérique C. Guinel   +5 more
doaj   +1 more source

A Graphical User Interface Application to Model Open‐System Melting in the Upper Mantle

Geochemistry, Geophysics, Geosystems, Volume 27, Issue 8, August 2026.
Abstract The mantle partial melting process is crucial for the physicochemical evolution of the Earth's upper mantle and the generation of mafic crust. The open‐system melting model incorporates continuous melt segregation, interaction with melts or fluids, and crystallization of trapped melt and therefore provides a comprehensive model for simulating ...
I. Nishio, N. Akizawa, K. Ozawa, K. Itano, P. Waterton   +4 more
wiley   +1 more source