Detection and Reliability of Model Signatures in Paleomagnetic Time Series
Abstract
We model the geomagnetic field as a transient phenomenon, and therefore relative paleomagnetic intensity as a set of growths and decays, punctuated by occasional steady states. Our model originates from theory and experimental observations of rotating parametric instabilities that are possible in Earth's fluid outer core due to tidal and precessional strains. Since evaluation of this model using paleomagnetic time series depends on errors in both paleointensity and chronology, our analysis includes both sources of error. Accordingly, we have constructed an algorithm that recovers growth and decay rates from paleomagnetic time series. Our algorithm has been applied to both simulated data and relative paleointensity from ODP983 and NAPIS- 75. Analysis of simulated data returns estimates that agree with expected rates to within the calculated error. For real data from single records, recovered rates are consistent with earlier results using less objective methods, but can have errors as large as the rates themselves. Thus reliable rates and uncertainties of growth and decay rates need to be found from multiple time series and correlated to identifiable events.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMGP51B0765A
- Keywords:
-
- 1507 Core processes (1213;
- 8115);
- 1510 Dynamo: theories and simulations;
- 1521 Paleointensity