Magnetostratigraphy and Polarity Transition Studies in the Wai'anae Volcano: From the Gilbert-Gauss to the Upper Kaena Reversals

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9706997 Herrero-Bervera The PI proposes a study of geomagnetic polarity transitions recorded by lava flows of Wai'anae volcano. The PI has located and studied in detail two geomagnetic polarity transition boundaries in sections of the Wai'anae Volcano. Preliminary dating and measurements of the polarity of the transitions are consistent with the Gilbert-Gauss (R-N), Lower (N-R) and Upper Mammoth, Lower and Upper Kaena transitions. Samples will be dated further using K-Ar and Ar/Ar techniques to confirm this correlation. Progressive alternating-field demagnetization has been completed on preliminary samples drilled at widely-spaced vertical intervals in both sections to remove major lightning-induced and viscous secondary components efficiently, revealing well-grouped flow means. The PI will sample five transitional sections in detail and will complete a study of the magnetostratigraphy and polarity of the transitional fields. This work should help constrain the geometry of the geomagnetic field during polarity transitions. ***