Author
Blair Schoene
Other affiliations: Massachusetts Institute of Technology, University of Geneva
Bio: Blair Schoene is an academic researcher from Princeton University. The author has contributed to research in topics: Zircon & Geochronology. The author has an hindex of 43, co-authored 101 publications receiving 9291 citations. Previous affiliations of Blair Schoene include Massachusetts Institute of Technology & University of Geneva.
Topics: Zircon, Geochronology, Geology, Silicic, Pluton
Papers published on a yearly basis
Papers
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Academy of Sciences of the Czech Republic1, Charles University in Prague2, University of Bergen3, University of Nottingham4, Boise State University5, Goethe University Frankfurt6, Memorial University of Newfoundland7, Stockholm University8, University of Vienna9, University of Geneva10, Swedish Museum of Natural History11
TL;DR: The Plesovice zircon as discussed by the authors has a concordant U-Pb age with a weighted mean Pb-206/U-238 date of 337.13 +/- 0.37 Ma (ID-TIMS, 95% confidence limits, including tracer calibration uncertainty).
3,694 citations
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British Geological Survey1, University of Bergen2, University of Arizona3, Geological Survey of Canada4, University of Kansas5, University of Copenhagen6, Macquarie University7, Geoscience Australia8, Texas Tech University9, University College London10, College of Charleston11, Princeton University12
TL;DR: The LA-ICP-MS U-(Th-)Pb geochronology international community has defined new standards for the determination of U-(th)-Pb ages as discussed by the authors.
Abstract: The LA-ICP-MS U-(Th-)Pb geochronology international community has defined new standards for the determination of U-(Th-)Pb ages. A new workflow defines the appropriate propagation of uncertainties for these data, identifying random and systematic components. Only data with uncertainties relating to random error should be used in weighted mean calculations of population ages; uncertainty components for systematic errors are propagated after this stage, preventing their erroneous reduction. Following this improved uncertainty propagation protocol, data can be compared at different uncertainty levels to better resolve age differences. New reference values for commonly used zircon, monazite and titanite reference materials are defined (based on ID-TIMS) after removing corrections for common lead and the effects of excess 230Th. These values more accurately reflect the material sampled during the determination of calibration factors by LA-ICP-MS analysis. Recommendations are made to graphically represent data only with uncertainty ellipses at 2s and to submit or cite validation data with sample data when submitting data for publication. New data-reporting standards are defined to help improve the peer-review process. With these improvements, LA-ICP-MS U-(Th-)Pb data can be considered more robust, accurate, better documented and quantified, directly contributing to their improved scientific interpretation.
526 citations
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TL;DR: In this article, a comprehensive treatment of the derivation of U-Pb isotope ratios and their corresponding uncertainties from isotope dilution thermal ionization mass spectrometric measurements is presented.
Abstract: A comprehensive treatment of the derivation of U-Pb isotope ratios and their corresponding uncertainties from isotope dilution thermal ionization mass spectrometric measurements is presented. Standard parametric statistical methods of error propagation are utilized to convolve uncertainties associated with instrumental mass fractionation, tracer subtraction, blank Pb and U subtraction, and initial common Pb correction. Derivations include errors and error correlations for total sample U/Pb and Pb isotope ratios (including radiogenic and initial common Pb) for two- and three-dimensional isochron calculations, radiogenic U/Pb and Pb isotope ratios for concordia and radiogenic model age calculations, and the propagation of model age errors from radiogenic isotope ratios.
420 citations
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TL;DR: In this paper, the U-Pb systematics of zircon and xenotime on the single-to sub-grain scale by high-precision ID-TIMS geochronology on 11 rock samples ranging from 0.1 to 3.3 Ga.
418 citations
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TL;DR: In this paper, high-precision U/Pb geochronology from volcanic ashes was used to show that the Triassic-Juras-sic boundary and end-Triassic biological crisis from two independent marine stratigraphic sections correlate with the onset of terrestrial fl ood volcanism in the Central Atlantic Magmatic Province to <150 ka.
Abstract: New high-precision U/Pb geochronology from volcanic ashes shows that the Triassic-Juras- sic boundary and end-Triassic biological crisis from two independent marine stratigraphic sections correlate with the onset of terrestrial fl ood volcanism in the Central Atlantic Mag- matic Province to <150 ka. This narrows the correlation between volcanism and mass extinc- tion by an order of magnitude for any such catastrophe in Earth history. We also show that a concomitant drop and rise in sea level and negative δ 13 C spike in the very latest Triassic occurred locally in <290 ka. Such rapid sea-level fl uctuations on a global scale require that global cooling and glaciation were closely associated with the end-Triassic extinction and potentially driven by Central Atlantic Magmatic Province volcanism.
377 citations
Cited by
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University of Bergen1, Charles University in Prague2, Academy of Sciences of the Czech Republic3, University of Nottingham4, Boise State University5, Goethe University Frankfurt6, Memorial University of Newfoundland7, Stockholm University8, University of Vienna9, University of Geneva10, Swedish Museum of Natural History11
TL;DR: The Plesovice zircon as discussed by the authors has a concordant U-Pb age with a weighted mean Pb-206/U-238 date of 337.13 +/- 0.37 Ma (ID-TIMS, 95% confidence limits, including tracer calibration uncertainty).
3,694 citations
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01 Jan 2012
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.
Abstract: An Astronomically Tuned Neogene Time Scale (ATNTS2012) is presented, as an update of ATNTS2004 in GTS2004. The new scale is not fundamentally different from its predecessor and the numerical ages are identical or almost so. Astronomical tuning has in principle the potential of generating a stable Neogene time scale as a function of the accuracy of the La2004 astronomical solution used for both scales. Minor problems remain in the tuning of the Lower Miocene. In GTS2012 we will summarize what has been modified or added since the publication of ATNTS2004 for incorporation in its successor, ATNTS2012. Mammal biostratigraphy and its chronology are elaborated, and the regional Neogene stages of the Paratethys and New Zealand are briefy discussed. To keep changes to ATNTS2004 transparent we maintain its subdivision into headings as much as possible.
1,479 citations
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TL;DR: The basic principles of radiometric geochronology as implemented in a new software package called IsoplotR, which was designed to be free, flexible and future-proof, are reviewed.
Abstract: This paper reviews the basic principles of radiometric geochronology as implemented in a new software package called IsoplotR, which was designed to be free, flexible and future-proof. IsoplotR is free because it is written in non-proprietary languages (R, Javascript and HTML) and is released under the GPL license. The program is flexible because its graphical user interface (GUI) is separated from the command line functionality, and because its code is completely open for inspection and modification. To increase future-proofness, the software is built on free and platform-independent foundations that adhere to international standards, have existed for several decades, and continue to grow in popularity. IsoplotR currently includes functions for U-Pb, Pb-Pb, 40 Ar/ 39 Ar, Rb-Sr, Sm-Nd, Lu-Hf, Re-Os, U-Th-He, fission track and U-series disequilibrium dating. It implements isochron regression in two and three dimensions, visualises multi-aliquot datasets as cumulative age distributions, kernel density estimates and radial plots, and calculates weighted mean ages using a modified Chauvenet outlier detection criterion that accounts for the analytical uncertainties in heteroscedastic datasets. Overdispersion of geochronological data with respect to these analytical uncertainties can be attributed to either a proportional underestimation of the analytical uncertainties, or to an additive geological scatter term. IsoplotR keeps track of error correlations of the isotopic ratio measurements within aliquots of the same samples. It uses a statistical framework that will allow it to handle error correlations between aliquots in the future. Other ongoing developments include the implementation of alternative user interfaces and the integration of IsoplotR with other data reduction software.
1,320 citations
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TL;DR: 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.
1,261 citations
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TL;DR: Amber from northern Myanmar has been commercially exploited for millennia, and it also preserves the most diverse palaeobiota among the worlds' seven major deposits of Cretaceous amber.
1,139 citations