Magnetic characteristics and archeointensity determination on Mesoamerican Pre-Columbian Pottery from Quiahuiztlan, Veracruz, Mexico

Abstract

We report a detailed archeomagnetic investigation on pre-Columbian potteries from Quiahuiztlan, Veracruz, from ∼900 AD to 1521 AD. Archeological samples analyzed by modern magnetic techniques carry a stable univectorial thermoremanent magnetization under alternating field treatment. Continuous low-field susceptibility vs. temperature curves performed in air indicates Ti-poor titanomagnetites as magnetization carriers. Few samples, however, show two ferrimagnetic phases with Curie temperatures compatible with both Ti-poor and Ti-rich titanomagnetites. Hysteresis parameter ratios fall essentially in the pseudo-single-domain region, which may indicate a mixture of multi-domain and a significant amount of single domain grains. Early geomagnetic field intensity determinations using the Coe variant of Thellier method were performed on 90 selected samples. Cooling rate corrected intensity values range from 34.0 ± 1.2 to 62.2 ± 0.2 μT. Corresponding virtual axial dipole moments (VADM) range from 5.7 to 10.7 ×1022 Am2. Absolute intensity curves for Mesoamerica present limited spatial/temporal resolution. For tentative dating purposes, we used global archeointensity curves reduced to central and eastern Mexico that permit preliminary dating of Quiahuiztlan potteries. Comparison of our data against those reported in ArcheoInt database allow to identify two periods 900- 1000 and 1400-1600 AD as the most probable manufacturing ranges for the potteries studied.