Carson Geomorphology Field Notes – Day 4

Carson Day 4

7/16/09

C9 – 12

These cores were all placed on top of mound D – I decided I wanted to explore the surface of mound D a bit more and look around for some burned or buried floors. Turns out that I didn’t find any kind of structures through these cores – they all appeared similar to the upper layers of C8. None of these were excavated beyond 1.5 meters below surface and were not characterized. Kelsey on Friday will conduct down – hole magnetics on this surface to look for anthropogenic (living surfaces) layers in the first 1.5 meters. I believe placing these bore holes all over the top of the mound was a good idea, although a more systematic approach will be needed if I’m ever to find any buried structures. Also, another mound building stage is farther down below and we would do well to find it by coring deeper through the top of Mound D.

C13

Md A wstrn flank

This core was placed on the flank of mound A – we excavated this one approximately 4.5 meters below surface. first terrace overlooking channel 11It is about 4.4 meters from the first terrace overlooking the old channel 11 – the bank for this channel is about 14.4 meters away.

About 79 cmbs we hit a thick midden full of daub and charcoal – above this is a relatively ubiquitous light tan layer of what appears to be basket loading. In my notes I stipulate that this might indicate they were building the mound up over an older midden layer. Most likely, the first meter of this core suggests basket loading and then below is a premound midden which looks to be situated on an older natural levee.

core 13b ash lens

There is a distinct ash lens about 1.5 meters down, suggesting possibly the area was clear cut and burned before mound building occurred. It appears that perhaps an old natural levee was present and then the Indians burned down the natural shrubbery, etc, to make a habitable surface.

Click here to view large image of core 13

At the time of Mound A’s construction, channel 11 was most likely an oxbow or relict channel. At the bottom of the core we recovered a clay plug, possibly indicating ridge and swale topography or that a backswamp was present in the area.

C14

Excavated underneath an old pecan tree on the east side of Mound A – the first 60-70 cm all look like midden fill, which are full of daub and charcoal, then underneath this we found sandy levee soils. These levee soils were situated on top of a silted in, clayey landscape, suggesting again the older ridge and swail topography we can see on the landscape farther to the east.Core 14

C15 and C16

We excavated just one core length from this location, which is very close to the easement area where John Connaway and Ole Miss are working – we find again very similar materials to core 14. C16 is similar as well.

C17

This core was excavated in the pecan grove, south of Mound A.  It was also similar to c14 as we recovered heavy amounts of daub and clay in the first 60cm of soil – this area appears to be similar to the front side/middle area of a natural levee.

S7300484

Looking south from Mound A into the pecan grove.

C18 and C19 – both excavated in the pecan grove.

The former was unpenetrable and the latter we only excavated to about 1 meter before modern disturbances stopped us. We then continued C19 by using a hand auger to excavate the rest of the core. In this manner we were able to penetrate to about 3 meters down – I don’t have these data yet. Oddly enough, we found intact prehistoric soils underneath the modern layer above. Perhaps the modern soils were an intrusive layer from when the pool was constructed – we also recovered some small sherds from this core – Type Avenue Polychrome var. unspecified.

While walking around in the pecan grove,  we noticed a small, discrete ridge running along an east-west line with the same alignment as the embankment drawn on William Henry Holmes’ map. This was my first thorough walk-through of this area and was surprised to see how much this surface undulated.  Ed Henry and John Cappleman have done some geophysics out in the grove and I’m curious to see what their data reveal.

Advertisements

Leave a comment

Filed under Academic Ramblings

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s