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| Titel |
Enhanced climate variability in the tropics: a 200 000 yr annual record of monsoon variability from Pangea's equator |
| VerfasserIn |
R. Y. Anderson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 7, no. 3 ; Nr. 7, no. 3 (2011-07-19), S.757-770 |
| Datensatznummer |
250004609
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| Publikation (Nr.) |
 copernicus.org/cp-7-757-2011.pdf |
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| Zusammenfassung |
| A continuous series of 209 000 evaporite varves from the equator of arid
western Pangea (age = −255 ma), as a proxy for surface temperature, has a
complete suite of Milankovitch cycles and harmonics as expected for a
rectified reaction to precession-modulated insolation at the equator.
Included are modes of precession (23.4 kyr, 18.2 kyr), semi-precession
(11.7 kyr, 9.4 kyr), and harmonics at ~7 kyr and 5.4 kyr. An oscillation of
~100 kyr, with 35 % of total variance, originates as an amplitude
modulation of precession cycles. An exceptionally strong 2.3 kyr
quasi-bi-millennial oscillation (QBMO) appears to have had its own source of
forcing, possibly solar, with its amplitude enhanced at Milankovitch
frequencies. Seasonal information in varves traces the rectifying process to
asymmetrical distribution of Pangea relative to the equator, and its effect
on monsoonal circulation and heat flow near the equator during summer
solstices in the hemispheres. |
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