Absolute dating radiocarbon dating. The development of accelerator mass spectrometry (AMS) dating, which allows a date to be obtained from a very small sample, has been very useful in this regard. Other radiometric dating techniques are available for earlier periods. One of the most widely used is potassium–argon dating (K–Ar dating). Potassium-40 is a radioactive isotope of potassium that decays into argon-40. The half-life of potassium-40 is 1.3 billion years, far longer than that of carbon-14, allowing much older samples to be dated. Potassium is common in rocks and minerals, allowing many samples of geochronological or archeological interest to be dated. Argon,
Ixcateopan (archaeological site) de productos derivados del algodón, materia prima que debió ser la principal fuente de abasto y de culto en la región. The archaeological zone consists of a series of overlays built on a natural elevation of the terrain, which occupies approximately 5 thousand square meters. Construction materials employed include: stone slabs, marble, limestone, boulders; and stucco and red paint used for finishing. Ceramic artifacts are a large and important group of samples found, generally mentioned in archaeological reports, serve to describe as well as chronological placement of sites, although seldom are investigation and study specific subjects The typical ceramics used