Journal ArticleDOI
Synchronizing Rock Clocks of Earth History
Klaudia F. Kuiper,Klaudia F. Kuiper,Alan L. Deino,Frederik J Hilgen,Wout Krijgsman,Paul R. Renne,Paul R. Renne,Jan R. Wijbrans +7 more
TLDR
This calibration of tephras in marine deposits in Morocco to calibrate the age of Fish Canyon sanidine provides tight constraints for the astronomical tuning of pre-Neogene successions, resulting in a mutually consistent age of ∼65.95 Ma for the Cretaceous/Tertiary boundary.Abstract:
Calibration of the geological time scale is achieved by independent radioisotopic and astronomical dating, but these techniques yield discrepancies of ∼1.0% or more, limiting our ability to reconstruct Earth history. To overcome this fundamental setback, we compared astronomical and 40 Ar/ 39 Ar ages of tephras in marine deposits in Morocco to calibrate the age of Fish Canyon sanidine, the most widely used standard in 40 Ar/ 39 Ar geochronology. This calibration results in a more precise older age of 28.201 ± 0.046 million years ago (Ma) and reduces the 40 Ar/ 39 Ar method9s absolute uncertainty from ∼2.5 to 0.25%. In addition, this calibration provides tight constraints for the astronomical tuning of pre-Neogene successions, resulting in a mutually consistent age of ∼65.95 Ma for the Cretaceous/Tertiary boundary.read more
Citations
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Journal ArticleDOI
On The Geologic Time Scale
TL;DR: GTS2012 as mentioned in this paper summarizes the international divisions and ages in the Geologic Time Scale, published in 2012, since 2004, when GTS2004 was detailed, major developments have taken place that directly bear and have considerable impact on the intricate science of geologic time scaling.
Book ChapterDOI
The Neogene Period
TL;DR: An Astronomically Tuned Neogene Time Scale (ATNTS2012) is presented in this article, as an update of ATNTS2004 in GTS2004, and the numerical ages are identical or almost so.
Journal ArticleDOI
A chronology of Paleozoic sea-level changes.
Bilal U. Haq,Stephen R. Schutter +1 more
TL;DR: A history of sea-level fluctuations for the entire Paleozoic by using stratigraphic sections from pericratonic and cratonic basins is reconstructed, revealing a gradual rise through the Cambrian and a short-lived but prominent withdrawal in response to Hirnantian glaciation.
Journal ArticleDOI
The Placental Mammal Ancestor and the Post–K-Pg Radiation of Placentals
Maureen A. O'Leary,Maureen A. O'Leary,Jonathan I. Bloch,John J. Flynn,Timothy J. Gaudin,Andres Giallombardo,Norberto P. Giannini,Suzann L. Goldberg,Brian P. Kraatz,Brian P. Kraatz,Zhe-Xi Luo,Jin Meng,Xijun Ni,Michael J. Novacek,Fernando A. Perini,Zachary S. Randall,Guillermo W. Rougier,Eric J. Sargis,Mary T. Silcox,Nancy B. Simmons,Michelle Spaulding,Michelle Spaulding,Paúl M. Velazco,Marcelo Weksler,John R. Wible,Andrea L. Cirranello,Andrea L. Cirranello +26 more
TL;DR: A phylogenetic tree shows that crown clade Placentalia and placental orders originated after the K-Pg boundary, but phenomic signals overturn molecular signals to show Sundatheria (Dermoptera + Scandentia) as the sister taxon of Primates, a close link between Proboscidea and Sirenia (sea cows), and the monophyly of echolocating Chiroptera (bats).
Journal ArticleDOI
Joint determination of 40K decay constants and 40Ar∗/40K for the Fish Canyon sanidine standard, and improved accuracy for 40Ar/39Ar geochronology
Paul R. Renne,Paul R. Renne,Roland Mundil,Greg Balco,Greg Balco,Kyoungwon Min,Kenneth R. Ludwig +6 more
TL;DR: In this article, a statistical optimization approach was proposed for estimating the 40Ar/39Ar decay constants from 40K activity data, K-Ar isotopic data, and pairs of 238U-206Pb and 40Ar-39Ar data for rigorously selected rocks to estimate the partial decay constants (λe and λβ).
References
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Journal ArticleDOI
Subcommission on geochronology: Convention on the use of decay constants in geo- and cosmochronology
R.H. Steiger,E. Jäger +1 more
TL;DR: The IUGS Subcommission on Geochronology (FOOTNOTE 4) as discussed by the authors recommended the adoption of a standard set of decay constants and isotopic abundances in isotope geology.
Journal ArticleDOI
A long-term numerical solution for the insolation quantities of the Earth
Jacques Laskar,Philippe Robutel,F. Joutel,Mickael Gastineau,Alexandre C. M. Correia,Alexandre C. M. Correia,Benjamin Levrard +6 more
TL;DR: In this article, a new solution for the astronomical computation of the insolation quantities on Earth spanning from −250 m to 250 m was presented, where the most regular components of the orbital solution could still be used over a much longer time span, which is why they provided here the solution over 250 m.
BookDOI
A Geologic Time Scale 2004
TL;DR: Gradstein et al. as discussed by the authors proposed a chronostratigraphy approach for linking time and rock in the context of geologic time scales, including the geomagnetic polarity time scale and stable isotope geochronology.
Journal ArticleDOI
Intercalibration of standards, absolute ages and uncertainties in 40Ar/39Ar dating
Paul R. Renne,Paul R. Renne,Carl C. Swisher,Alan L. Deino,Daniel B. Karner,Thomas L. Owens,Donald J. DePaolo +6 more
TL;DR: McDougall et al. as mentioned in this paper derived intercalibration factors for McClure Mountain hornblende (MMhb-1), GHC-305 biotite, GA-1550, Taylor Creek sanidine (TCs), relative to Fish Canyon sanidine(ACs), were derived from 797 analyses involving 11 separate irradiations with well-constrained neutronfluence variations.
Related Papers (5)
Subcommission on geochronology: Convention on the use of decay constants in geo- and cosmochronology
R.H. Steiger,E. Jäger +1 more