Spiro Mounds Archeological Park, Spiro, Oklahoma

Spiro Mounds Archeological Park along the banks of the Arkansas River in Eastern Oklahoma represents one of the four most important archeological sites east of the Rockies.  It was here that a great city, with over 10,000 citizens stood between 800-1400 AD during the time period known as the Mississippian Period.

Turtle Shell Art Showing Shamans Controlling the Rains

If those dates sound familiar, that is because it also coincides with the period of maximum population and development of the Puebloan cultures of the Desert Southwest. But, Spiro was not one of those. Instead, it's cultural affinities were directed east. Spiro was the site of a major trade route along the Arkansas River and between the Ozarks and Ouachitas that connected tribes of the Great Plains, Rocky Mountains, and Mexico to those of the Mississippi Valley and the Southeast. As such, this site had both access to almost every conceivable trade item and great power in controlling what went where.

Copper ceremonial items found in Spiro Mounds

The cultural influences were immense as well. These artifacts, including native copper from the Great lakes, looks more like what you'd expect from the Maya or Aztecs, than what you see from Puebloan cultures.

So, why did Spiro get so large and so important and then get abandoned around 1450?

A re-creation of a typical house of the Spiro period

The period between 800-1200 AD was a time of almost perfect weather conditions in the southern half of the continent. The winters were mild and the rains regular. It rained frequently, but not heavily. These conditions allowed tribes from Arizona to the Carolinas to grow massive quanities of corn, squash, and beans. There were so many surpluses, that they could start to focus on other aspects of culture, such as building religious structures and elaborate ceremonies. They could afford to trade for ceremonial or luxury items such as conch shells from Florida, obsidian from Oregon, copper from Michigan, and even macaw feathers from South America.

Some of the Mounds

A political elite began to form around the religious/ceremonial class. They essentially convinced the populus that the weather was good and the food surpluses existed because of their influence on the sun, earth, and rain. And, for 300+ years, it sure seemed that way. An occassional bad year could easily be explained away by other means.

This line cut in the grass is the angle the sun sets on the summer soltice.
It is hard to see in the image, but several of the mounds were aligned on this axis.

Then, around 1200 AD things began to change. The weather patterns shifted. Rather than regular light rains, they'd get bursts of torrential rain followed by months of drought. It wasn't that the average rainfall changed significantly, just the pattern. As such, torrential downpours would come in the spring washing away seeds and sprouts. Then what survived would die as an extended drought would begin.

Hilina learning how to grind corn into flour

This created political instability as people began to turn toward their religious/political elite. This in-turn caused them elites to consolidate and strenghten their hold on power through ever increasing harsh measures. Eventually, as these conditions continued for several decades, the entire social structure began to break down. Rather than adapting to the new conditions, people simply began to disperse into other areas, and by 1450 AD the site was abandoned.

Some "turtle" art

So, how did we find out all of this information? Well, due to state budget cuts, they have laid off all of the workers at the site, except for the site director. He is now the guy at the desk greeting people. He also happens to be an Archeologist who got his PhD working at the Spiro site in the 1970-80's while at the University of Oklahoma. Not only was he a fountain of knowledge, but he was very interested in sharing that information with us.