Abstract
Abstract. 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.
Subject
Paleontology,Stratigraphy,Global and Planetary Change
Reference56 articles.
1. Anati, D. A.: The hydrography of a hypersaline lake, in: The Dead Sea: The Lake and its Setting, edited by: Niemi, T. M., Ben-Avraham, Z., and Gat, Z. R., Oxford Monograph on Geology and Geophysics, 89–103, 1997.
2. Anderson, R. Y.: A long geoclimatic record from the Permian, J. Geophys. Res., 87, 7285–7294, 1982.
3. Anderson, R. Y., Dean Jr., W. E., Kirkland, D. W., and Snider, H. J.: Permian varved Castile evaporite sequence, west Texas and New Mexico, Geol. Soc. Am. Bull., 83, 59–86, 1972.
4. Berger, A. and Loutre, M. F.: Pre-Quaternary Milankovitch frequencies, Nature, 342, 133–134, 1989.
5. Berger, A., Loutre, M. F., and Mélice, J. L.: Equatorial insolation: from precession harmonics to eccentricity frequencies, Clim. Past, 2, 131–136, https://doi.org/10.5194/cp-2-131-2006, 2006.
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