Evidence for a new geomagnetic reversal from Lava flows in Idaho: Discussion of short polarity reversals in the Brunhes and late Matuyama polarity chrons

摘要: K-Ar ages and paleomagnetic data for basalt samples from a new core hole (site E) at the Idaho National Engineering Laboratory (INEL) indicate that age of reversed polarity event recorded in Snake River Plain lavas is older than 465±50 ka (1000 years before present) reported previously by Champion et al. (1981). Nine flows, eight with normal one polarity, were recognized site E hole. The flows above below flow have 491±80 580±93 ka, respectively. inclination field direction agrees elsewhere INEL which an 565±14 ka. These thought to be correlative Emperor event. We suggest this we name Big Lost Reversed Polarity Subchronozone Subchron. A review documenting short reversal records volcanic sedimentary rocks shows there evidence subchrons Brunhes two besides Jaramillo late Matuyama. 10 begin many events Cox (1968) hypothesized must exist if interval lengths Poisson distribution. are true subchrons, not excursions, may or low associated paleointensities, although strengths might explain why process aborts. mean sustained length since Matuyama Chron time 90,000 years. similarity number 105-year period Earth's orbital eccentricity suggests anew linkage between geomagnetic, paleoclimatic, possible underlying Earth parameters should evaluated.