Show simple item record

dc.contributor.authorTominaga, Masako
dc.contributor.authorSager, William W.
dc.date.accessioned2010-06-28T15:58:58Z
dc.date.available2010-06-28T15:58:58Z
dc.date.issued2010-05-12
dc.identifier.citationGeophysical Journal International 182 (2010): 203-232en_US
dc.identifier.urihttp://hdl.handle.net/1912/3699
dc.descriptionAuthor Posting. © The Authors, 2010. This article is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 182 (2010): 203-232, doi:10.1111/j.1365-246X.2010.04619.x.en_US
dc.description.abstractThe current M-anomaly geomagnetic polarity timescale (GPTS) is mainly based on the Hawaiian magnetic lineations in the Pacific Ocean. M-anomaly GPTS studies to date have relied on a small number of magnetic profiles, a situation that is not ideal because any one profile contains an uncertain amount of geologic 'noise' that perturbs the magnetic field signal. Compiling a polarity sequence from a larger array of magnetic profiles is desirable to provide greater consistency and repeatability. We present a new compilation of the M-anomaly GPTS constructed from polarity models derived from magnetic profiles crossing the three lineation sets (Hawaiian, Japanese and Phoenix) in the western Pacific. Polarity reversal boundary locations were estimated with a combination of inverse and forward modelling of the magnetic profiles. Separate GPTS were established for each of the three Pacific lineation sets, to allow examination of variability among the different lineation sets, and these were also combined to give a composite timescale. Owing to a paucity of reliable direct dates of the M-anomalies on ocean crust, the composite model was time calibrated with only two ages; one at each end of the sequence. These two dates are 125.0 Ma for the base of M0r and 155.7 Ma for the base of M26r. Relative polarity block widths from the three lineation sets are similar, indicating a consistent Pacific-wide spreading regime. The new GPTS model shows slightly different spacings of polarity blocks, as compared with previous GPTS, with less variation in block width. It appears that the greater polarity chron irregularity in older models is mostly an artifact of modelling a small number of magnetic profiles. The greater averaging of polarity chron boundaries in our model gives a GPTS that is statistically more robust than prior GPTS models and a superior foundation for Late Jurassic–Early Cretaceous geomagnetic and chronologic studies.en_US
dc.description.sponsorshipThis work was supported by the Jane & R. Ken Williams'45 Chair of Ocean Drilling Science and Technology.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherJohn Wiley & Sonsen_US
dc.relation.urihttp://dx.doi.org/10.1111/j.1365-246X.2010.04619.x
dc.subjectMagnetic anomalies: modelling and interpretationen_US
dc.subjectReversals: process, time scale, magnetostratigraphyen_US
dc.subjectMarine magnetics and palaeomagneticsen_US
dc.titleRevised Pacific M-anomaly geomagnetic polarity timescaleen_US
dc.typeArticleen_US
dc.identifier.doi10.1111/j.1365-246X.2010.04619.x


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record