Backyard Geology Adventures: Special Archaeology Edition Part 2

Jen over at Sprite’s Keeper hosts a fun little thing every week called The Spin Cycle.  This week was a free-for-all, so I decided, what the hey?  I’ll try it!

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This is a continuation of my previous post about archaeology in the southwest, and what kinds of things I found and learned about in the Arizona desert.

Agriculture

Agricultural tradition in the Southwestern U.S. originally came from Mexico.  In 3000 BC, people were growing corn, beans and squash, and other plants were added over the years.  Irrigation was used to adapt the southwest to farming conditions of the wetter Mexican crops.

Archaeologists recognize prehistoric agricultural sites in the field by the presence of agricultural terraces, like those in the picture shown below.  We found quite a few of these as well, and this one was the most obvious.

prehistoric agricultural terraces, humans for scale

They will often be found in a cleared area with little to no artifacts and tend to have less vegetation than the surrounding areas, due to extended use of the soil and depletion of nutrients.

FUN FACT!  Growing too much corn in one spot over a long period of time takes all the iron out of the soil and causes anemia in people who eat it.  Image from here.

One of the later plants used by the prehistoric people was the agave, which grew as both a native and a cultivated plant.  Agave prefer to grow in rocky, well drained soil, like in the picture shown here.

Prehistoric people planted agave in rock piles, which can still be seen today, without the agave.

Image from here

Some species of agave, like Murphy’s Agave, were developed specifically for cultivation.  Murphy’s Agave doesn’t flower like most other agave species do, but instead sprouts little agaves that can be picked off and planted somewhere else.

(I couldn’t find a picture of this.  boo! …  Our teacher just told us about it.  I really would like to see what it looks like.)

Well, I think that’s enough for today.  I have one more topic to write about in my little archaeology series, but you will just have to wait for the final edition until a later date!