Analysis of the age and paleomagnetic orientation of the Broadwell Mesa Basalt, Bristol Mountains, CA

Geoffrey Phelps; John Hillhouse; Robert J. Fleck; David M. Miller; David C. Buesch; Andrew J. Cyr; Kevin M. Schmidt

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USGS · 70196903

Analysis of the age and paleomagnetic orientation of the Broadwell Mesa Basalt, Bristol Mountains, CA

Geoffrey Phelps·John Hillhouse·Robert J. Fleck·David M. Miller·David C. Buesch·Andrew J. Cyr·Kevin M. Schmidt

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Abstract

To add to the regional paleomagnetic data documenting block rotation in eastern California, we determined the age and paleomagnetic rotation of the Broadwell Mesa basalt, a basalt in the Bristol Mountains, CA as part of an effort to constrain the timing and rotation of blocks adjacent to the fault. The east-striking sinistral Broadwell Mesa fault cuts and separates the basalt into two outcrops. An 40Ar/39Ar date from the northern outcrop yields an age of 5.46 ± 0.04 Ma. Two sites consisting of 40 paleomagnetic cores from the basalt indicate the basalt is reversely magnetized and that there has been no significant rotation (< 11º) between the two basalt outcrops.

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Source-reported bounding extent: 35.04798673426734° to 44.88895839978044° latitude; -116.27243041992188° to -109.94293212890625° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Geoffrey Phelps, John Hillhouse, Robert J. Fleck, David M. Miller, David C. Buesch, Andrew J. Cyr, Kevin M. Schmidt. 2017. Analysis of the age and paleomagnetic orientation of the Broadwell Mesa Basalt, Bristol Mountains, CA. https://pubs.usgs.gov/publication/70196903

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