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Millennial-scale climate changes manifest Milankovitch combination tones and Hallstatt solar cycles in the Devonian greenhouse world
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SYSNO ASEP 0503957 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Millennial-scale climate changes manifest Milankovitch combination tones and Hallstatt solar cycles in the Devonian greenhouse world Author(s) da Silva, A.C. (BE)
Dekkers, M. J. (NL)
De Vleeschouwer, D. (NL)
Hladil, Jindřich (GLU-S) RID, SAI
Chadimová, Leona (GLU-S) RID, SAI
Slavík, Ladislav (GLU-S) RID, SAI, ORCID
Hilgen, F. J. (NL)Source Title Geology. - : Geological Society of America - ISSN 0091-7613
Roč. 47, č. 1 (2019), s. 19-22Number of pages 4 s. Publication form Print - P Language eng - English Country US - United States Keywords origin ; record ; variability ; cyclicity ; band Subject RIV DB - Geology ; Mineralogy OECD category Geology Method of publishing Limited access Institutional support GLU-S - RVO:67985831 UT WOS 000454902700007 EID SCOPUS 85062867597 DOI 10.1130/G45511.1 Annotation Sub-Milankovitch rhythmic features in sedimentary records have been reported from throughout geological time. However, their origin remains enigmatic, in particular during so-called greenhouse periods in Earth's history. To better understand such short-term climatic changes, we sampled two 3-m-thick intervals of early Devonian hemipelagic carbonate at 1 cm resolution in the Pod Barrandovem section (Czech Republic). Greenhouse conditions prevailed during early Devonian times, and the chosen resolution enables the detection of millennial-scale climate change as recorded by elemental abundances. We used a previously published astrochronology for the section to transform the studied series from the stratigraphic into the time domain. Spectral analysis of the time-calibrated log-transformed Ti records reveal obliquity and precession cycles, confirming the applied astrochronology. Additional spectral peaks with periods of 2.3-2.7, 6-8, and 10-12 k.y. appear in both records. Furthermore, a 1.5 k.y. periodicity, close to the Pleistocene Dansgaard-Oeschger oscillation, is also identified, but only in the record with higher accumulation rate (similar to 3.5 cm/k.y.). Bi-coherence spectra reveal that the 6-8 and 10-12 k.y. periodic components are combination tones of Milankovitch cycles. We infer the shorter similar to 2.5 k.y. periodicity to be the result of solar forcing, related to the Hallstatt cycle. These new observations strengthen the case for an external origin of millennial-scale features. Workplace Institute of Geology Contact Jana Popelková, popelkova@gli.cas.cz, Sabina Janíčková, Tel.: 233 087 272 Year of Publishing 2020 Electronic address https://pubs.geoscienceworld.org/gsa/geology/article/47/1/19/567354/Millennialscale-climate-changes-manifest
Number of the records: 1