La Quemada: Decline and abandonment in two stages on the classic period northern frontier of Mesoamerica

Abstract

An integrated magnetic survey was carried out on key places within the La Quemada archaeological complex, built over a hill on the northern frontier of Classic period Mesoamerica. Samples were collected from the Plaza of Sacrifices and Hall of Columns in an attempt to precisely determine the age intervals corresponding to the decline and abandonment of the site, apparently due to the intentional firing as a closure ritual. Well-defined characteristic remanent magnetizations were retrieved from 23 of 32 samples. Moreover, twelve samples belonging to two areas yielded reliable determinations under criteria curtailed in this study. In any case, a primary remanent magnetization is carried by pseudo-single-domain Ti-poor titanomagnetite, as evidenced by hysteresis and continuous thermomagnetic curves. The archaeomagnetic dating was performed using full geomagnetic vector (directions and absolute intensity) using the last SHADIF14k model. The Plaza of Sacrifices seems to been burned between a time interval from 854 to 968 CE, while a late interval from 1018 to 1163 CE is assigned to the samples collected in the Hall of Columns, which suggest the gradual abandonment of the site. The first abandonment stage is almost synchronous to the same phenomena observed for other sites at the Bajío area (central and western Mesoamerica) region. Under these circumstances, it cannot be discarded that La Quemada was burned in its entirety during the first stage of abandonment, but the Hall of Columns was again burned later.