Results 91 to 100 of about 96,687 (276)

U‐Pb Geochronology of Paleosol Carbonate Cements by LA‐ICP‐MS: A Proof of Concept and Strategy for Dating the Terrestrial Record

open access: yesGeochemistry, Geophysics, Geosystems
This study investigates the potential of laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) U‐Pb dating for carbonate nodules in the Late Triassic Ischigualasto Formation of northwestern Argentina.
L. E. Aguirre Palafox   +5 more
doaj   +1 more source

Investigating relationships among strontium, barium, and seasonality in wild baboons

open access: yesArchaeometry, EarlyView.
Abstract Geochemical profiles of Australopithecus africanus and baboon teeth show fluctuating trace elements, possibly reflecting seasonal diets. Here we use laser ablation–inductively coupled plasma–mass spectrometric measurements of calcium‐normalized strontium and barium ratios (Sr/Ca and Ba/Ca) and ion microprobe analyses of oxygen isotopes (δ18O ...
Maya Bharatiya   +12 more
wiley   +1 more source

Impact and Correction of Analytical Positioning on Accuracy of Zircon U-Pb Dating by SIMS

open access: yesFrontiers in Chemistry, 2020
Secondary ion mass spectrometry (SIMS) is one of the most important analytical tools for geochronology, especially for zircon U-Pb dating. Due to its advantages in spatial resolution and analytical precision, SIMS is the preferred option for multi-spot ...
Yu Liu   +13 more
doaj   +1 more source

Electron Microprobe Chemical Dating of Uraninite as a Reconnaissance Tool for Leucogranite Geochronology [PDF]

open access: yes, 2007
We suggest that electron microprobe techniques may be employed to date Tertiary samples of uraninite (UO~2~), which can contain very high concentrations of radiogenic Pb after only a few million of years of U and Th decay. Although uraninite is regarded
Jahandar Ramezani   +4 more
core   +1 more source

Zircon U-Pb dating of Mesozoic volcanic and tectonic events in northwest Palmer Land and southwest Graham Land, Antarctica [PDF]

open access: yes, 2009
New whole rock Rb-Sr and zircon U-Pb geochronological data and Sm-Nd isotopic data are presented from the central magmatic arc domain of the Antarctic Peninsula in the area of northwest Palmer Land and southwest Graham Land, Rb-Sr isochrons indicate an ...
Flowerdew, Michael   +5 more
core   +1 more source

Trace Element Patterns in Juvenile Wild Chimpanzee Dentitions

open access: yesArchaeometry, EarlyView.
ABSTRACT Trace elements are used to infer mammalian early‐life diets, environmental toxins, dispersal patterns, stress histories, and weaning ages. Here, we employ laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) to reveal elemental patterns in our closest living relatives, chimpanzees.
Tanya M. Smith   +5 more
wiley   +1 more source

Detrital zircon and apatite (U‐Th)/He geochronology of intercalated baked sediments: a new approach to dating young basalt flows [PDF]

open access: yes, 2011
Simple numerical models suggest that many basaltic lava flows should sufficiently heat the sediments beneath them to reset (U‐Th)/He systematics in detrital zircon and apatite.
Aciego   +32 more
core   +2 more sources

Alpha-recoil in U?Pb geochronology: effective sample size matters

open access: yesContributions to Mineralogy and Petrology, 2003
Displacement of the daughter isotope by α-recoil results in an open system on the nanoscale. For a heterogeneous distribution of U and Th, this redistribution of intermediate and stable daughter isotopes results in subvolumes with a deficit of Pb and others with an excess of Pb.
openaire   +3 more sources

Untangling nutrient co‐regulation of ombrotrophic peatland development

open access: yesBoreas, EarlyView.
Multi‐method (FTIR, FT‐NIR and TGA) approaches characterizing the organic peat constituents at Holcroft Moss reveal a record of switches that reflect broadly hydroclimate variability governing the decomposition patterns. There are periods, however, where hydroclimate does not fully explain the variability observed and instead changes appear linked to ...
Richard C. Chiverrell   +6 more
wiley   +1 more source

The Lomagundi-Jatuli carbon isotopic event recorded in the marble of the Tandilia System basement, Río de la Plata Craton, Argentina [PDF]

open access: yes, 2019
The “Lomagundi-Jatuli event” corresponds to the most important δ13C positive anomaly (≥5‰) globally reported in Palaeoproterozoic marine carbonates (between ∼2.30 and 2.06 Ga).
Ballivian Justiniano, Carlos Alberto   +6 more
core   +1 more source

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