Integration of volcanic and sedimentary records of paleointensity: Constraints imposed by irregular eruption rates

The reading of absolute paleointensity by lava flows has been simulated by sampling the field intensities from dipole (extracted from sedimentary pale ointensities) and non dipole (similar to the present field) components. Res ults show that specific features in the geomagnetic intensity cannot be rep roduced unless a minimum of 10 flows per 100 ky have been emitted. However, this criteria does not guaranty the high quality of the record, which depe nds also on the temporal control. For cases where the volcanic activity is episodic, a minimum of 4 dated flows per 100 ky is suggested. The construct ion of a composite curve from volcanic paleointensity, intended as a type-c urve of field intensity changes, requires a very large number of data in or der to overcome the effects of non-dipole components, errors in ages, and v ariable sampling. The present volcanic database is far from having this res olution to perform this analysis for the last 800 ky.