ODP Site 1063 (Bermuda Rise) revisited: Oxygen isotopes, excursions and paleointensity in the Brunhes Chron

• Main Authors: Channell, J. E. T., Hodell, D. A., Curtis, J. H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2012
• Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems; Iceland
• Online Access: http://eprints.esc.cam.ac.uk/2458/; http://eprints.esc.cam.ac.uk/2458/1/2011GC003897.pdf; http://www.agu.org/pubs/crossref/2012/2011GC003897.shtml

An age model for the Brunhes Chron of Ocean Drilling Program (ODP) Site 1063 (Bermuda Rise) is constructed by tandem correlation of oxygen isotope and relative paleointensity data to calibrated reference templates. Four intervals in the Brunhes Chron where paleomagnetic inclinations are negative for both u-channel samples and discrete samples are correlated to the following magnetic excursions with Site 1063 ages in brackets: Laschamp (41 ka), Blake (116 ka), Iceland Basin (190 ka), Pringle Falls (239 ka). These ages are consistent with current age estimates for three of these excursions, but not for “Pringle Falls” which has an apparent age older than a recently published estimate by ∼28 kyr. For each of these excursions (termed Category 1 excursions), virtual geomagnetic poles (VGPs) reach high southerly latitudes implying paired polarity reversals of the Earth's main dipole field, that apparently occurred in a brief time span (<2 kyr in each case), several times shorter than the apparent duration of regular polarity transitions. In addition, several intervals of low paleomagnetic inclination (low and negative in one case) are observed both in u-channel and discrete samples at ∼318 ka (MIS 9), ∼412 ka (MIS 11) and in the 500–600 ka interval (MIS 14–15). These “Category 2” excursions may constitute inadequately recorded (Category 1) excursions, or high amplitude secular variation.