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Intercalibration of standards, absolute ages and uncertainties in 40Ar/39Ar dating
Synchronizing Rock Clocks of Earth History
- K. Kuiper, A. Deino, F. Hilgen, W. Krijgsman, P. Renne, J. Wijbrans
- Geology, PhysicsScience
- 25 April 2008
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.
Joint determination of 40K decay constants and 40Ar∗/40K for the Fish Canyon sanidine standard, and improved accuracy for 40Ar/39Ar geochronology
A test for systematic errors in 40Ar/39Ar geochronology through comparison with U/Pb analysis of a 1.1-Ga rhyolite
Response to the comment by W.H. Schwarz et al. on Joint determination of 40K decay constants and 40
2.5-million-year-old stone tools from Gona, Ethiopia
The artefacts show surprisingly sophisticated control of stone fracture mechanics, equivalent to much younger Oldowan assemblages of Early Pleistocene age, which indicates an unexpectedly long period of technological stasis in the Oldowan.
On the ages of flood basalt events
2.6-Million-year-old stone tools and associated bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia.
Age and Timing of the Permian Mass Extinctions: U/Pb Dating of Closed-System Zircons
Zircons from nine ash beds within the Shangsi and Meishan sections (China), pretreated by annealing followed by partial attack with hydrofluoric acid, result in suites of consistent and concordant uranium/lead (U/Pb) ages, eliminating the effects of lead loss.
Environment and behavior of 2.5-million-year-old Bouri hominids.
The combined evidence suggests that behavioral changes associated with lithic technology and enhanced carnivory may have been coincident with the emergence of the Homo clade from Australopithecus afarensis in eastern Africa.