Simultaneous presence of orbital inclination and eccentricity in proxy climate records from Ocean Drilling Program Site 806

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doi: 10.1130/0091-7613(1997)025<0003:SPOOIA>2.3.CO;2
Author(s): Muller, Richard A.; MacDonald, Gordon J.
Author Affiliation(s): Primary:
University of California at Berkeley, Department of Physics, Berkeley, CA, United States
International Institute for Applied Systems Analysis, Laxenburg, Austria
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 25(1), p.3-6. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. 16 refs.; illus.
Summary: Ocean Drilling Program Site 806 in the western Pacific shows evidence of a remarkably constant average sedimentation rate. This feature allows us to analyze ancient climate proxies without the need for "orbital tuning," a standard procedure in prior work, but one that can lead to biased results. Spectral analysis of stable oxygen isotope ratios at this site, a proxy for global ice volume, shows a single narrow peak with a period ∼100 k.y., a result that supports our model which links glacial cycles to variations in the inclination of the Earth's orbit. In contrast, spectral analysis of the coarse component fraction of the sediment (primarily foraminifera) shows a structure characteristic of standard Milankovitch theory, with a triplet of peaks with periods near those expected from the Earth's eccentricity: 95, 125, and 400 k.y. Bispectral analysis confirms these linkages but suggests that orbital inclination also plays some role in the coarse fraction. From the clear presence of both signals in different proxies at the same site, we conclude that although eccentricity affected the local climate, it is orbital inclination that drove the variations in the global ice volume for the past million years.
Year of Publication: 1997
Research Program: ODP Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; 24 Surficial Geology, Quaternary Geology; Cenozoic; Eccentricity; Equatorial Pacific; Foraminifera; Invertebrata; Leg 130; Marine sedimentation; Marine sediments; Microfossils; Milankovitch theory; ODP Site 806; Obliquity of the ecliptic; Ocean Drilling Program; Pacific Ocean; Paleoclimatology; Planktonic taxa; Protista; Quaternary; Sedimentation; Sedimentation rates; Sediments; Upper Quaternary; West Pacific
Coordinates: N001906 N001907 E1592142 E1592140
Record ID: 1997017063
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