| one publication added to basket [295895] | The Cretaceous-Paleogene boundary and its 405-kyr eccentricity cycle phase: a new constraint on radiometric dating and astrochronology
Hennebert, M. (2014). The Cretaceous-Paleogene boundary and its 405-kyr eccentricity cycle phase: a new constraint on radiometric dating and astrochronology. Carnets de Géologie = Notebooks on Geology 14(8-9): 173-189. https://dx.doi.org/10.4267/2042/53981
In: Carnets de Géologie = Notebooks on Geology. Carnets de Géologie: Brest. e-ISSN 1634-0744, more
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| Author keywords |
Cretaceous-Paleogene boundary; astrochronology; eccentricity; time scale |
| Abstract |
Radiometric dating and astrochronologic dating still suffer discrepancies without knowing which one gives the most reliable results. A new tool is proposed to constrain both the approaches. The phase of the 405-kyr signal with respect to the Cretaceous - Paleogene boundary event has been determined in the Ain Settara section (Kalaat Senan, central Tunisia). We use this phase value (Option 2), as well as an average of phase values obtained from the literature (Option 1), to examine the relationship linking both the radiometric (absolute) age assigned to the K-Pg boundary and the Cenozoic average-value of the similar to 405-kyr eccentricity period. A new useful constraint emerges: to any absolute age assumed for the K-Pg boundary corresponds a value of the mean Cenozoic 405-kyr period, and vice versa. Supposing a K-Pg boundary radiometric age in the vicinity of 66.0 Ma, then the number of entire cycles (comprised between two minima of the 405-kyr eccentricity signal) within the Cenozoic Period could only be equal to 163. When adding to this figure the parts of the cycles preceding and following these 163 entire cycles the total duration of the Cenozoic Era becomes equal to 163.168 cycles (Option 1) or 163.081 cycles (Option 2). We propose to grant a special interest to the determination of the 405-kyr cycle phase at stratigraphically well documented levels, particularly those that correspond to world-wide, sudden and catastrophic events, that are well located in time by reliable radiometric dates. |
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