TERRAPUB Earth, Planets and Space

Earth Planets Space, Vol. 57 (No. 5), pp. 465-470, 2005


Geomagnetic paleointensity over 1.2 Ma from deep-tow vector magnetic data across the East Pacific Rise

Michiko Yamamoto1, Nobukazu Seama2, and Nobuhiro Isezaki3

1Earth and Atmospheric Sciences, Cornell University, Snee Hall, Ithaca, NY 14853, U.S.A.
2Research Center for Inland Seas, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
3Department of Earth Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan

(Received November 8, 2004; Revised March 31, 2005; Accepted April 6, 2005)

Abstract: Deep-tow vector magnetic data have been acquired across the fast-spreading southern East Pacific Rise 18S and inverted to magnetization intensity variations. Vector magnetic data are used to determine continuous magnetic intensity within intervals of constant polarity over the Matuyama and Brunhes periods up to the Cobb Mountain event at 1.19 Ma. A comparison of our deep-tow vector data and a sediment core-derived geomagnetic paleointensity timescale suggests that the short-wavelength magnetic anomaly signal is indeed of geomagnetic origin and can be used to date the seafloor with a high resolution. The crustal age determined from our date reveals a highly asymmetric spreading rate for the recent period (since 0.3 Ma).
Key words: Paleointensity variation, vector magnetic anomaly data, deep-tow survey, East Pacific Rise.

Corresponding author E-mail: michiko@geology.geo.cornell.edu

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