The Trincheras Culture

With the arrival of agriculture, and centered in the region of the Altar River, a culture we know as the Trincheras developed (We can see a diagram of it on the right. Click on it to see it larger)

It has received that name because their most important manifestation were hills covered with walls and terraces formed with rocks, without mortar. This name comes fom the Spanish name for trenches. In the accompanying diagram we can see their location in time.

It was thought, until recently, that those hills of trincheras were defensive in nature, however, recent research has modified that interpretation.

This culture has been also divided into several stages. (Click on the diagran on the left, to see it larger) The first stage, Archaic, is characterized by the lack of ceramics, and corresponds essentially to a collecting and hunting style of life.

Then, the Atil phase follows, which apparently began around 200 AD, and ended, also possibly, around 800 AD, although it might have finished even later. It is characterized by the appearance of ceramics made with the coil and anvil technique, that is to make vessels with a roll of clay, which then is hit with a flat instrument to flatten it, to form the walls of the vessel.

The analysis of the ceramic styles of these first phases of the Trincheras culture, suggests affinities between it and the rest of the coastal traditions of the Pacific Coast of Mexico: the Seris, Guaymas and the Huatabampo culture.

Their habitants, during this stage, lived in small hamlets of semi subterranean houses, disseminated along the margins of rivers and creeks, which suggests they practiced agriculture.

Then, the Altar phase follows, which starts around 800 AD, and ends between 1100 to 1300 AD. It is characterized by a dramatic increase in the number, size and variety of cultural manifestations. During this phase the hills of trincheras began to be built, which in this phase weren´t accompanied by constructions, like homes, and some of them were located far from the creeks and other sources of food and water. This suggests a ceremonial use for them.

Besides this, in the floodplain were built larger sized hamlets than in the previous stage, some of whom had nearby hills of trincheras. Also, during this stage the large scale trade of seashell started with other regions. They collected the seashells in the coast, and at the same site they gave them the first stages of finishing. Then, they took them to their inland hamlets, where the last stages of the process of transforming them into jewelry were made. After finishing them, they were traded with other regions locater further inland.

To this, the Realito phase will follow, ending possibly around 1450 AD. It is characterized by a decrement of inhabited sites, although those constructed then are larger in size, which suggests a greater concentration of population. Besides this, the hamlets moved from the floodplain to the nearby mesa tops.

During this phase, the construction of hills of trincheras decreased in size, while apparently those that remained from the previous stage were abandoned.

However, during this phase the famous hill of trincheras that gave the culture it´s name was built. It is located just outside of the Trincheras town (You can click on the image at the left, to see a larger sized image). Also, you can also have and aerial view of the site, here.

During this phase, the seashell trade continued, while the ceramic technique of construction of ceramics was changed, from the traditional of coil and anvil, to another named paddle and anvil, in which the potter holds a supporting tool, the anvil, on the inside of the vessel, while striking the outside with a paddle. This innovation in the technique is the same one used among the Hohokm and all the other cultures of the region. All of these changes suggest a profound cultural modification during this stage for the Trincheras culture.

The Santa Teresa phase follows, and ends with the arrival of the Jesuit missionaries in 1690. During this phase, there was a dramatic decrease in the population of the region, accompanied by the abandonement of many of the cultural patterns that characterized it, and will correspond to the generalized cultural decline that starts around 1250 AD. Also, during this stage the construction of hills of trincheras decreased enormously.

The style of life of this stage corresponds essentially to that found by the Spaniards when they arrived at the Pimeria Alta. It is thought that the Tohono O´odham of historic times are descendants from this two latest stages of the Trincheras culture.