Deep-tow magnetic anomaly study of the Pacific Jurassic Quiet Zone and implications for the geomagnetic polarity reversal timescale and geomagnetic field behavior


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dc.contributor.author Tominaga, Masako
dc.contributor.author Sager, William W.
dc.contributor.author Tivey, Maurice A.
dc.contributor.author Lee, Sang-Mook
dc.date.accessioned 2010-07-13T14:03:52Z
dc.date.available 2010-07-13T14:03:52Z
dc.date.issued 2008-07-26
dc.identifier.citation Journal of Geophysical Research 113 (2008): B07110 en_US
dc.identifier.uri http://hdl.handle.net/1912/3744
dc.description Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): B07110, doi:10.1029/2007JB005527. en_US
dc.description.abstract The Jurassic Quiet Zone (JQZ) is a region of low-amplitude magnetic anomalies whose distinctive character may be related to geomagnetic field behavior. We collected deep-tow magnetic profiles in Pigafetta Basin (western Pacific) where previous deep-tow data partially covered the JQZ sequence. Our goals were to extend the survey through the JQZ, examine anomaly correlations, and refine a preliminary geomagnetic polarity timescale (GPTS) model. We collected a series of closely spaced profiles over anomaly M34 and Ocean Drilling Program Hole 801C to examine anomaly correlation in detail, one profile in between previous profiles, and two long profiles extending the survey deeper into the JQZ. Anomaly features can be readily correlated except in a region of low-amplitude, short-wavelength anomalies in the middle of the survey area (“low-amplitude zone” or LAZ). The small multiprofile surveys demonstrate anomaly linearity, implying that surrounding anomalies are also linear and likely result from crustal recording of geomagnetic field changes. We constructed a GPTS model assuming that most anomalies result from polarity reversals. The polarity timescale is similar to the polarity sequences from previous studies, but its global significance is uncertain because of problems correlating anomalies in the LAZ and the ambiguous nature of the small JQZ anomalies. Overall anomaly amplitude decreases with age into the LAZ and then increases again, implying low geomagnetic field strength, perhaps related to a rapidly reversing field. Other factors that may contribute to the LAZ are interference of anomalies over narrow, crustal polarity zones and poorly understood local tectonic complexities. en_US
dc.description.sponsorship This research was supported by the National Science Foundation grants OCE-0099161 and OCE-0099237. Tominaga was partly supported by funds from the Jane and R. Ken Williams ’45 Chair in Ocean Drilling Science, Education, and Technology. en_US
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dc.language.iso en_US en_US
dc.publisher American Geophysical Union en_US
dc.relation.uri http://dx.doi.org/10.1029/2007JB005527
dc.subject Magnetic anomalies en_US
dc.subject Pacific Jurassic Quiet Zone en_US
dc.subject Geomagnetic polarity en_US
dc.subject Timescales en_US
dc.title Deep-tow magnetic anomaly study of the Pacific Jurassic Quiet Zone and implications for the geomagnetic polarity reversal timescale and geomagnetic field behavior en_US
dc.type Article en_US
dc.identifier.doi 10.1029/2007JB005527

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