Paleomagnetic and rock magnetic data show that 36-24 Ma ignimbrite outflow sheets in the Mogollon-Datil volcanid field carry thermoremanent magnetizations (TRMs) that provide useful, reliable correlation criteria. Over 90% of 404 ignimbrite sites exhibit well-grouped (α95500 m) intracaldera ignimbrite sequences agree in polarity with associated outflow sheets but show less consistent TRM directions, probably reflecting syncooling secular variation and discrepancies between eutaxitic foliations and the syncooling paleohorizontal.

Mean virtual geomagnetic pole positions (VGPs) of normal and reverse polarity ignimbrites are nearly antipodal (175.6¿ apart), showing no evidence of long term differences in the zonal harmonics of the normal and reverse polarity states. Less antipodal mean VGPs (161.2¿ apart) from normal and reverse polarity lavas are interpreted as defects in the data set, probably including incompletely removed normal polarity viscous overprints. The mean paleomagnetic pole position for Mogollon-Datil ignimbrites (n=68 independent unit-mean VGPs) is located at (78.8¿N, 166.6¿E, K=19.8, A95=4.0, &sgr;=18.2¿). ¿1991 American Geophysical Union