Inspect the soil where the artifact was found. Soil forms distinct layers over time, so if you find an artifact in a deeper level of the soil, it is older than artifacts in higher strata. This process is known as stratigraphy, but it can only provide a relative date, not an absolute date. Some objects may also come from a site where the culture left a calendar: the Mayans and Aztecs kept meticulous calendrical records which can be converted to modern time and give a very precise date.
Examine the material and style of the artifact. As Pre-Columbian civilizations evolved, they used stronger materials, and the design of their artifacts became more complex. Thus, if you are trying to date a piece of Inca pottery, you can compare it to other types of Inca pottery and determine where your piece fits in the evolution of pottery in that area. This method, called seriation, will also only give you a relative date, unless some artifact in the series has already been dated by another method.
Send any organic materials to a lab to measure the statistical count of beta radiations given off by the artifact. This method, known as Carbon-14 dating, dates objects by calculating the beta radiations of Carbon-14 isotopes, which give off less radiations as they age. However, because of the high amount of naturally occurring radioactive particles in South American soils, this method is often inaccurate, and it can only provide a range of dates, with a margin of error as large as several hundred years. For artifacts from a civilization like the Inca, which only lasted a few hundred years, this method is relatively unhelpful. It also cannot accurately determine the age of recent objects or objects over 50,000 years old.
Heat any pottery to over 500 degrees Celsius and measure the intensity of the light released. All ceramic objects are heated in order to harden them for use. Afterwards, they begin to store light energy. Thus, the intensity of the light released by reheating will indicate how long it has been since the object was last heated.
Send any rocks to a lab to measure the ratio of potassium to argon. Because the rate of decay of the potassium isotope is constant, the lab can compare the ratio of these two elements This method is useful for any materials that are more than 50,000 years old. However, this method requires the presence of past volcanic activity. Some areas of Mexico, like the Valsequillo site, provide such conditions. Fission tracking, which measures the rate of tracks left by radioactive uranium, can be used to corroborate the potassium-argon method.