Results 181 to 190 of about 156,667 (215)
Some of the next articles are maybe not open access.
Zircon U-Pb ages for the Early Cambrian time-scale
Journal of the Geological Society, 1992Single zircons from two Early Cambrian volcanic horizons have been analysed using the SHRIMP ion microprobe. Full details of the analytical procedures and data reduction are given. Zircons from tuff within the Lie de Vin Formation, near Tiout, Morocco, show little spread in U-Pb age and have a mean value of 521 ± 7 Ma (2σ).
Compston, W. +4 more
openaire +2 more sources
A minimum UPb age for Siberian flood-basalt volcanism
Geochimica et Cosmochimica Acta, 1996Abstract Establishing an accurate and precise age for Siberian flood-basalt volcanism is of great importance in evaluating causes for the unequaled mass extinction of flora and fauna at the Permian-Triassic boundary. We report a new, minimum UPb age obtained from zircon and baddeleyite from the mineralized Noril'sk I intrusion that cuts the lower ...
S.L. Kamo, G.K. Czamanske, T.E. Krogh
openaire +1 more source
A U–Pb age for mineralized Nipissing diabase, Gowganda, Ontario
Canadian Journal of Earth Sciences, 1986Concordant baddeleyite and rutile analyses from mineralized Nipissing diabase at Gowganda's Castle mine yield a U–Pb age of [Formula: see text]. Baddeleyite is a primary phase of the diabase; therefore the age dates the magmatic emplacement. The genesis of rutile is less certain: rutile could have formed during an episode of alteration, veining, and ...
F. Corfu, A. J. Andrews
openaire +1 more source
Decay constant errors in U–Pb concordia-intercept ages
Chemical Geology, 2000Abstract Although almost universally ignored, the effect of errors in the uranium decay-constants on U–Pb concordia-intercept ages (and Pb–Pb ages) are significant, and not equivalent to those of simple U–Pb ages. Equations are derived for concordia-intercept age-errors that take decay-constant errors into account.
openaire +1 more source
U-Pb age constraints on dinosaur rise from south Brazil
Gondwana Research, 2018Abstract Triassic dinosaurs from South Brazil are considered as some of the oldest known worldwide, but their precise correlation to other early dinosaur occurrences have proven difficult. The problem of such long-distance faunal correlations has been exacerbated by reliance on an equivocal tetrapod biostratigraphy and the lack of palynomorphs and ...
Max C. Langer +2 more
openaire +1 more source
U–Pb zircon ages for the Rice Lake area, southeastern Manitoba
Canadian Journal of Earth Sciences, 1989The Archean Rice Lake greenstone belt in southeastern Manitoba is made up of mafic to felsic volcanic rocks and associated intrusive and metasedimentary rocks. The belt is flanked to the north by the Wanipigow River granitic complex and to the south by the Manigotagan gneissic belt.
A. Turek +3 more
openaire +1 more source
Precambrian U-Pb zircon ages from Western Galicia(NW Spain)
Earth-Science Reviews, 1980Abstract Zircon and monazite U-Pb ages are reported from two orthogneiss samples and one paragneiss from western Galicia. The three investigated suites of zircons reveal upper intercept ages of 2.2–2.5 Ga and lower intercept ages of about 470 Ma. The discordia pattern of the paragneiss is interpreted as resulting from lead loss of a detrital zircon ...
openaire +1 more source
U-PB EMPLACEMENT AGES OF KANSAS LAMPROITES AND KIMBERLITES
Geological Society of America Abstracts with Programs, 2023Isabella Lupini +3 more
openaire +1 more source
UNMIXING DETRITAL ZIRCON U-PB AGE DISTRIBUTIONS
Geological Society of America Abstracts with Programs, 2017Kurt E. Sundell, Joel E. Saylor
openaire +1 more source
Integrative oncology: Addressing the global challenges of cancer prevention and treatment
Ca-A Cancer Journal for Clinicians, 2022Jun J Mao,, Msce +2 more
exaly