Refining the Early Devonian time scale using Milankovitch cyclicity in Lochkovian–Pragian sediments (Prague Synform, Czech Republic)

0464292 - GLÚ 2017 RIV NL eng J - Journal Article
da Silva, A.C. - Hladil, Jindřich - Chadimová, Leona - Slavík, Ladislav - Hilgen, F. J. - Bábek, O. - Dekkers, M. J.
Refining the Early Devonian time scale using Milankovitch cyclicity in Lochkovian–Pragian sediments (Prague Synform, Czech Republic).
Earth and Planetary Science Letters. Roč. 455, 1 December (2016), s. 125-139. ISSN 0012-821X. E-ISSN 1385-013X
R&D Projects: GA ČR GA14-18183S
Institutional support: RVO:67985831
Keywords : orbital time scale * spectral analysis * Devonian * magnetic susceptibility * gamma ray spectrometry * limestone * Early Devonian * Lochkovian * Pragian * Emsian * Barrandian * peri-Gondwanan basins
Subject RIV: DB - Geology ; Mineralogy
Impact factor: 4.409, year: 2016

Based on detailed magnetic susceptibility and also gamma-ray spectrometric data series, the structure of Milankovitch cyclicity record has been computed using the latest achievements of Meyers's Astrochron Program Package. The reliability of analysis of multiple spectral features has further been increased using the techniques of Continuous Wavelet Transform, Evolutive Harmonic Analysis, Multi-taper Method and Average Spectral Misfit, all with the effort to make the study more secure against phenomena of gapped andor significantly varying nature of the records, and to reach an optimal astronomical interpretation. The age model in this study results in durations as follows 7.7 ±2.8 Myr for the Lochkovian Stage (7.7 ±2.6 Myr for the Lochkov Formation in the stratotype area) and 1.7 ±0.7 Myr for the Pragian Stage that is trimmed due to extremely low, current position of the GSSP base of the Emsian stage (5.7 ±0.6 Myr for the Praha Fm. which continues into Lower Emsian where is capped by basal Zlichovian rocks). Besides the 18 kyr and other relatively short-period cycles (often with heterodyne-features), the 100 and 405 kyr eccentricity signals seem to be considerably strong, and even 1 and ~2.0-2.5 Myr long-period cycles are well manifested. It means the revision of the chronostratigraphic-stage durations, reducing also the uncertainty in the related part of the Time Scale.
Permanent Link: http://hdl.handle.net/11104/0263229