ISSN:
1420-9136
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Summary Thirty eight cores from five Miocene lavas and their underlying baked zones from South Eastern Oregon have provided a test for the Alternating Field method of determining geomagnetic paleointensities, by allowing external consistency tests as well as internal consistency tests. All specimens were run regardless of the reliability tests results. The susceptibility change reliability test is useful as some of the specimens which failed it nevertheless gave misleadingly plausible results, but is shown to be unsufficient, as some specimens which were retained on that test failed to yield valid results. Different specimens from the same core behaved differently during the various experiments, proving that two specimens from a same core cannot reliably be assumed to be identical. A relation between the oxidation state and a change of susceptibility upon heating is seen. The paleofield intensities varied from 0.17±0.04 Oe and 0.31±0.08 Oe, corresponding to Virtual Dipole Moments of 1.23×1025 to 2.15×1025 Oe cm3. These low values are not accompanied by Virtual Geomagnetic Pole instability, but suggest an instability of the strength of the main dipole.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00876179
