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Age calibrated relative paleointensity for the last 1.5 Myr at IODP Site U1308 (North Atlantic)

Age calibrated relative paleointensity for the last 1.5 Myr at IODP Site U1308 (North Atlantic)
Age calibrated relative paleointensity for the last 1.5 Myr at IODP Site U1308 (North Atlantic)
Integrated Ocean Drilling Program (IODP) Site U1308 (central North Atlantic) records paleomagnetic directional and relative paleointensity (RPI) variations for the last 1.5 Myr, in 110 m of the sediment sequence at a mean sedimentation rate of 7.3 cm/kyr. A detailed benthic oxygen isotope record was combined with RPI to produce an integrated, high-resolution magneto-isotopic stratigraphy for Site U1308. Apart from the well-known polarity reversals in this interval, the Punaruu excursion is recorded at 1092 ka and the Cobb Mountain Subchron in the 1182–1208 ka interval. The paleointensity proxies are determined as slopes of NRM versus ARM and NRM versus ARMAQ (ARM acquisition) with linear correlation coefficients to monitor the quality of the linear fit. The RPI record for Site U1308 is compared with the three other paleointensity records (one from the Western Equatorial Pacific and two from the North Atlantic) that cover the same time interval and have accompanying oxygen isotope records. The Match protocol of Lisiecki and Lisiecki (2002) is used to optimize the correlation of paleointensity records. Beginning with the original (published) age models for each record, the Match routine is used to optimize the RPI correlations to Site U1308, with checks to ensure compatibility with oxygen isotope records. Squared wavelet coherence (WTC) indicates significant improvement in RPI (and oxygen isotope) correlations after matching each RPI record to Site U1308, particularly for periods > 10 kyr. The level of coherence for the Atlantic RPI records and the lower resolution Pacific record implies synchronous global variability (at scales > 10 kyr) that can be attributed to the axial dipole geomagnetic field.

geomagnetic paleointensity, oxygen isotope stratigraphy, quaternary, signal correlation
0012-821X
59-71
Channell, J.E.T.
f37676da-640c-4bdc-8f9f-e2ffa43fe449
Hodell, D.A.
9f55a984-300c-40b9-8f10-ed47d62b46c6
Xuan, C.
3f3cad12-b17b-46ae-957a-b362def5b837
Mazaud, A.
3127d8d6-5892-477b-ad1f-7147bc7b84ca
Stoner, J.S.
7470dbc1-c6ff-4c08-b98c-3be4d1d43c2a
Channell, J.E.T.
f37676da-640c-4bdc-8f9f-e2ffa43fe449
Hodell, D.A.
9f55a984-300c-40b9-8f10-ed47d62b46c6
Xuan, C.
3f3cad12-b17b-46ae-957a-b362def5b837
Mazaud, A.
3127d8d6-5892-477b-ad1f-7147bc7b84ca
Stoner, J.S.
7470dbc1-c6ff-4c08-b98c-3be4d1d43c2a

Channell, J.E.T., Hodell, D.A., Xuan, C., Mazaud, A. and Stoner, J.S. (2008) Age calibrated relative paleointensity for the last 1.5 Myr at IODP Site U1308 (North Atlantic). Earth and Planetary Science Letters, 274 (1-2), 59-71. (doi:10.1016/j.epsl.2008.07.005).

Record type: Article

Abstract

Integrated Ocean Drilling Program (IODP) Site U1308 (central North Atlantic) records paleomagnetic directional and relative paleointensity (RPI) variations for the last 1.5 Myr, in 110 m of the sediment sequence at a mean sedimentation rate of 7.3 cm/kyr. A detailed benthic oxygen isotope record was combined with RPI to produce an integrated, high-resolution magneto-isotopic stratigraphy for Site U1308. Apart from the well-known polarity reversals in this interval, the Punaruu excursion is recorded at 1092 ka and the Cobb Mountain Subchron in the 1182–1208 ka interval. The paleointensity proxies are determined as slopes of NRM versus ARM and NRM versus ARMAQ (ARM acquisition) with linear correlation coefficients to monitor the quality of the linear fit. The RPI record for Site U1308 is compared with the three other paleointensity records (one from the Western Equatorial Pacific and two from the North Atlantic) that cover the same time interval and have accompanying oxygen isotope records. The Match protocol of Lisiecki and Lisiecki (2002) is used to optimize the correlation of paleointensity records. Beginning with the original (published) age models for each record, the Match routine is used to optimize the RPI correlations to Site U1308, with checks to ensure compatibility with oxygen isotope records. Squared wavelet coherence (WTC) indicates significant improvement in RPI (and oxygen isotope) correlations after matching each RPI record to Site U1308, particularly for periods > 10 kyr. The level of coherence for the Atlantic RPI records and the lower resolution Pacific record implies synchronous global variability (at scales > 10 kyr) that can be attributed to the axial dipole geomagnetic field.

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More information

Published date: 30 September 2008
Keywords: geomagnetic paleointensity, oxygen isotope stratigraphy, quaternary, signal correlation
Organisations: Ocean and Earth Science

Identifiers

Local EPrints ID: 351199
URI: https://eprints.soton.ac.uk/id/eprint/351199
ISSN: 0012-821X
PURE UUID: 77d27e22-6bc5-4336-a562-d762b1058755
ORCID for C. Xuan: ORCID iD orcid.org/0000-0003-4043-3073

Catalogue record

Date deposited: 16 Apr 2013 10:26
Last modified: 06 Jun 2018 12:24

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Contributors

Author: J.E.T. Channell
Author: D.A. Hodell
Author: C. Xuan ORCID iD
Author: A. Mazaud
Author: J.S. Stoner

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