Oligocene-Miocene relative (geomagnetic) paleointensity correlated from the Equatorial Pacific (IODP Site U1334 and ODP Site 1218) to the South Atlantic (ODP Site 1090)

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doi: 10.1016/j.epsl.2013.11.028
Author(s): Channell, J. E. T.; Lanci, L.
Author Affiliation(s): Primary:
University of Florida, Department of Geological Sciences, Gainesville, FL, United States
Other:
University of Urbino, Italy
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, Vol.387, p.77-88. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. 46 refs.; illus., incl. sketch map
Summary: Late Oligocene to early Miocene relative paleointensity (RPI) proxies can be correlated from the equatorial Pacific (IODP Site U1334 and ODP Site 1218) to the South Atlantic (ODP Site 1090). Age models are constrained by magnetic polarity stratigraphy through correlation to a common geomagnetic polarity timescale. The RPI records do not contain significant power at specific (orbital) frequencies, and hence there is no significant coherency between RPI proxies and the normalizers used to construct the proxies, although orbital power is present in some normalizers. There is no obvious control on RPI proxies from mean sedimentation rate within polarity chrons, magnetic grain size proxies or magnetic concentration parameters. The salient test is whether the equatorial Pacific records can be correlated one to another, and to the records from the South Atlantic. All records are dominated by RPI minima at polarity reversals, as expected, although the comparison within polarity chrons is compelling enough to conclude that the intensity of the Earth's axial dipole is being recorded. This is supported by the fit of RPI data from Sites U1334 and 1218 after correlation of the two sites using diverse core-scanning data, rather than polarity reversals alone. We do not see a consistent relationship between polarity-chron duration and mean RPI, and no consistent skewness ("saw-tooth" pattern) for RPI within polarity chrons. Stacks of RPI records for 17.5-26.5 Ma include long-term changes in RPI on Myr timescales that are superimposed on RPI minima associated with polarity reversals, and shorter-term variations in RPI with an apparent pacing of ∼50 kyr. The equatorial Pacific to South Atlantic correlations indicate that RPI can be used as a (global) stratigraphic tool in pre-Quaternary sediments with typical pelagic sedimentation rates of a few cm/kyr. Abstract Copyright (2014) Elsevier, B.V.
Year of Publication: 2014
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Anhysteretic remanent magnetization; Atlantic Ocean; Cenozoic; Correlation; East Pacific; Equatorial Pacific; Expedition 320; Expeditions 320/321; Grain size; IODP Site U1334; Integrated Ocean Drilling Program; Isothermal remanent magnetization; Leg 177; Leg 199; Magnetic susceptibility; Magnetization; Miocene; Natural remanent magnetization; Neogene; North Pacific; Northeast Pacific; ODP Site 1090; ODP Site 1218; Ocean Drilling Program; Oligocene; Pacific Ocean; Paleogene; Paleomagnetism; Remanent magnetization; Reversals; Sedimentation rates; South Atlantic; Tertiary
Coordinates: N080000 N080000 W1315824 W1315824
N085300 N085300 W1352200 W1352200
S425449 S425449 E0085359 E0085359
Record ID: 2014038739
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands