Ages of the Fish Canyon Sanidine Standard and the K–Pg Boundary
Uncertainties in the ages of the K–Pg boundary and the Fish Canyon sanidine (FCs) Ar–Ar sanidine dating standard, and in the number and tuning of 405-kyr eccentricity-related cycles, hamper the construction of a reliable tuned time scale for the Palaeogene, a critical time period marked by the occurrence of hyperthermals and the onset of ice-house conditions. Here, we present new results from integrated stratigraphic studies, including U–Pb, Ar–Ar, and astronomical intercalibration. These studies were conducted largely within the framework of the Marie Curie ITN GTSnext in an attempt to solve the discrepancies. Our results are overall consistent with an age of ~28.20 Ma for the FCs, the presence of 25 \(\times\) 405-kyr cycles in the Palaeocene, and an age of ~65.95 Ma for the K–Pg boundary.
KeywordsGeological time scale U–Pb dating Ar–Ar dating Astronomical dating K–Pg boundary FCs
- Renne, P. R., Greg Balco, G., Ludwig, K. R., Mundil, R., Min, K., et al. (2011). Response to the comment by W.H. Schwarz on “Joint determination of 40K decay constants and 40Ar*/40K for the Fish Canyon sanidine standard, and improved accuracy for 40Ar/39Ar geochronology” by P.R. Renne et al. (2010). Geochimica et Cosmochimica Acta,75, 5097–5100.CrossRefGoogle Scholar
- Vandenberghe, N., Hilgen, F. J., & Speijer, R. P. (2012). The Paleogene period. In F. Gradstein, J. Ogg, M. Schmitz, & G. Ogg (Eds.), The geological time scale 2012 (pp. 855–921). Amsterdam: Elsevier.Google Scholar