A rock-magnetic and paleointensity study of some Mexican volcanic lava flows during the Latest Pleistocene to the Holocene

摘要: Eleven Late Quaternary lava flows were sampled in the Chichinautzin volcanic field of central Mexico to determine their magnetic characteristics and absolute paleointensity. The samples studied cover a geological time interval approximately 0.39 My 2000 years. Several rock-magnetic experiments carried out order identify carriers obtain information about paleomagnetic stability. Continuous susceptibility measurements with temperature most cases yield reasonably reversible curves Curie points close that almost pure magnetite, which is compatible low-Ti titanomagnetite resulting from oxi-exsolution. Judging ratios hysteresis parameters, it seems all fall within pseudo-single domain grain size region, probably indicating mixture multidomain significant amount single grains. Forty-two belonging six independent cooling units yielded acceptable paleointensity estimates. NRM fractions used for determination range 0.34 0.97 quality factors varies between 4.5 97.8, being normally greater than 5. obtained virtual dipole moment values are higher those recently reported past 5 present day geomagnetic strength. Individual around BP substantially intensity, broad agreement worldwide archeomagnetic results.