Magnetic alteration of zero-age oceanic basalt

Citation:
Kent, DV, Gee J.  1996.  Magnetic alteration of zero-age oceanic basalt. Geology. 24:703-706.

Date Published:

Aug

Keywords:

de-fuca ridge, geomagnetic paleointensities, glass, grain-size, hysteresis, nonstoichiometry, oxidation, pillow basalts, submarine, titanomagnetites

Abstract:

The youngest sampled submarine lava flow, which erupted June 1993 on the Juan de Fuca Ridge, provides the basis for a tight constraint on the initial or zero-age magnetization state of MORE, Detailed profiles of magnetic hysteresis parameters, Curie temperatures, and unblocking temperatures of NRM with respect to the chilled margin of a pillow fragment show evidence of significant oxidation, which preferentially affected the finest grain-size fraction and principal remanence carrier of the titanomagnetite magnetic mineralogy. The oxidation must have occurred during or immediately after initial cooling, implying that MORE is already appreciably magnetically altered before aging. Nevertheless, successful results of Thellier paleointensity experiments on the basalt sample lend support to the idea that crustal magnetization represented by MORE preserves a record of geomagnetic intensity variations that may be reflected in small-scale magnetic anomalies.

Notes:

n/a

Website

DOI:

10.1130/0091-7613(1996)024<0703:maozao>2.3.co;2