Backyard Geology Adventures: Special Archaeology Edition Part 3

Life has been pretty crazy lately and new things are coming up constantly, but it’s about time I finished this thing off, so… enjoy!

If you missed my two original posts on this topic you can go here:

Part 1

Part 2

All right, now that we’re all caught up, let’s continue.  Where was I? Ahh, yes, I had just finished talking about growing agave and later remembered I had not mentioned what the prehistoric people actually used the agave for.

Well, they used it for a couple things.  What they did was take something (like a stick) and use it as a lever-type device to pry the agave plant out at its root.  The bottom of an agave is sort of like an artichoke, and the prehistoric people would cook it in a roasting pit.  Evidence of a prehistoric roasting pit is something called slag.  In geology, slag means the stuff that comes out of an iron furnace.  In archaeology, as I found out, it also means burnt soil from a roasting pit.  It looks like this:

Which reminds me, there’s other burnt old stuff, that provides evidence for an archaeological site.  This is burnt daub.

It’s adobe from a stone structure that burned down and collapsed.  Cool, huh?

Anyway, back to the agave.  The leaves were also useful.  Their insides are made of fibers that could be used for making cloth and baskets and other stuff you use fibers for.  That’s about it for the agave.  I have one more thing to talk about.

Trade

Prehistoric trade became very complexto the point where products were being manufactured and traded by specialists. Trade products included:

Pottery

Pottery appears to be coming from several different areas as part of a sophisticated trade economy.  The many different types of pottery are seen most commonly today as “sherds” or little pieces of broken pottery.  Here’s some of the coolest ones I found.

This one is sitting on top of a piece of tuff, which often indicates a doorway in a prehistoric structure. Like a doorstep.

The best ceramics were made in the earliest times and became more simple and coarse as time went on.  This concept can be compared to similar changes in modern manufacturing with changes in the economy.

Luxury Items

Shells from the Pacific Coast of California, near LA, were easy to manipulate into jewelry and transport to make a large profit.

Turquoise, another luxury item, was rare and transported long distances.

Other Products

Other products brought to trade were heavy rock baskets made out of igneous rock; axes made of green diorite (mass produced); products made of obsidian, hematite, chert and quartz; baskets; finished clothing; etc.

Oh, and one more thing…

Pretty much all these artifacts can be found not only at the living sites themselves, but also in prehistoric garbage dumps called trash mounds. Yep, the prehistoric people had landfills too!

That’s about all I’ve got.  Hope you enjoyed it.  I ruined a perfectly good pair of jeans trying to get all this information.

But I had a lot of fun and saw some really cool stuff.  I went to the art museum,

picnicked in the park,

and stayed at a pretty amazing hotel.

Fun times.  Just another day in the life of a soil scientist.

Stay tuned for my next adventure in the wilderness!

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!

Backyard Geology Adventures: Special Archaeology Edition

Well, this is an odd weekend.  The good news is, Matt got a job! (yay!), the bad news… we now have completely opposite work schedules (boo!).  So now I get to do things that I normally would not do when he is around, like things I used to do six months ago when I was single.  Including: spending hours at the mall (check) and playing on the internet whenever I feel like it without having someone complaining about how I am obsessed with facebook (also check).  Since I have this multitude of time on my hands, I thought I’d regale you with tales of my archaeological adventures in the wilderness.  Because it is an awesome story, and you WILL like it.

I was in Arizona for a total of two weeks taking this course.  For some of the time, we were sitting in a classroom learning about the history of prehistoric people in the southwest (in particular the general area that makes up the Tonto National Forest in Arizona).  The best classroom day was when we got to look at artifacts and then try to figure out what they were. The rest of the time, we were out in the field, either learning about stuff or doing archaeological surveys.

An archaeological survey is kind of fun to do but I can see how it could get somewhat repetitive and tedious after a while.  Basically, it involves walking up and down transects of your study area while looking down at the ground for any type of historic or prehistoric artifacts and structures that might be there.  In some places there may be absolutely nothing (which is good if you want to use the site for some sort of project, but not very exciting).  In other places, like where we were, there is tons of stuff.

This is some of what we found:

Housing

Types of architecture went through several different phases.  Early prehistoric people known as the Hohokam started out building pithouses around 1000 AD.  Pit houses were simple structures that were dug out and covered with mud for the walls, which were held up by wooden posts.

cross section of a pithouse

It’s really hard to find pithouses today because they’re made of dirt, and they collapsed a long time ago.  The only way to identify a potential pithouse site is to find an artifact scatter including items corresponding to the time period during which pithouses were built.  We may have found a couple of these sites, but like I said, it’s hard to tell.  One in particular was a pretty crazy site.  The first thing we noticed were a bunch of broken CD’s all over the place.  Some people were looking at them, trying to figure out what kinds of CD’s they were when we started stumbling across artifacts.  Lots of them.  Pottery sherds and lithics all over the place.  One lady in class picked up a giant agave knife and gave it to the teacher without even knowing what it was.  But the best find of the day was this:

arrowhead/projectile point

None of us could believe it.  We were standing around listening to our teacher talk about some stuff when one of the guys behind me noticed it on the ground.  It was really cool, and I was totally jealous I hadn’t found it myself.  If only I’d been standing back a little further…

Although, as it turns out, I’m not exactly the best at spotting things.  On a different day, my surveying partner Stella and I tripped right over another type of housing made a little later by the Hohokam.  This type of structure was made out of rock and we actually ended up finding quite a few of them over the course of the week, once we knew what we were looking for.  At this point, all you can really see is the outline of the walls, which may or may not be clear.  Ideally this is what it would look like, in map layout fashion:

Cross section of a rock structure, not to scale. Those black things are supposed to be rocks. Do not mock my mad artistic skills.

In reality, it looks more like this:

But sometimes you get lucky and can see good walls that are still standing, like this:

Or obviously collapsed walls, like this:

notice the alignment of the rocks here (going sideways across the picture)

There’s quite a bit more to say but now that I’ve written all of this, I’m pretty tired of it for today and will save the rest of the story for later.

Somehow we’ll make it, ’cause that’s what we do

I suppose I should update this thing, since some stuff has happened, as is bound to occur from time to time.  And also because I now have the hookup…the internet hookup, that is.  I also have a whole 5 tv channels!  Yes!  Now all I need is some furniture, which is coming early–next weekend as a matter of fact! 

Now that I have the internet at home, I suppose I’ll be spending less time at The Flying Star, which is probably a good thing.  Except that when I was there the other night, some guy came up to me and wanted me to help him figure out how to get on a website.  And then he paid me for helping him.  Isn’t that weird?  Oh well, if people are willing to give me money, I’m most definitely willing to take it.

But Maureen, you may ask, what about the job?  Ahh, yes, the job.  The reason I came here in the first place.  Well… it’s a job.  I have to get a paycheck before I can actually do anything worth doing, so most of the time I just sit around reading things my boss gave me about soil, plants, climate and archaeology.  The archaeology stuff is actually pretty interesting.  It’s got me wondering about how societies develop.  Why is it that European society developed one way and Native American society developed another way?  Does it have to do with environment, a difference in intelligence level, or necessity?  I have noo idea. 

I could say more but I’m getting lazy and I have to get up early for work tomorrow so that will be it for now.  More later.