Mayan limekilns as geomagnetic field recorders

Abstract

We report new results from frontier research that relates the methodology and knowledge of geophysics (geomagnetism) with archeology and the data will represent a valuable contribution to both disciplines. A detailed magnetic survey was performed on limekilns from the northern Yucatan peninsula. We used Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopy to determine the temperature of calcination in order to select limekiln samples that were heated above the Curie temperature for common magnetic minerals. Using rock-magnetism, we identified the main carrier of remanent magnetization to be multi-domain or large pseudo-single domain low titanium titanomagnetite. Alternating magnetic field demagnetizations delivered reliable archaeomagnetic directions. Our summary of 12 limekiln ages shows a large span from 707 to 1900 yr AD. Such a wide time range signifies that Maya used limekilns in the Yucatan peninsula area in the Late Classic period (600 AD), and that some of these limekilns were reused in the Colonial period. From a geophysical point of view, information can be used about the behavior of the Earth's magnetic field in the recent historical past in Mesoamerica. In this context, the hundreds of Mayan limekilns which are distributed in large areas, open great opportunities to contribute to both archeology and geomagnetic field fluctuations during the past two millennia.