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Cooper’s Ferry in the News and A New Feature

Posted by: | July 26, 2010 | 3 Comments |

The OSU Cooper’s Ferry Archaeology Field School was featured in two local newspapers recently. Here are the links to these articles:

Idaho County Free Press

Cottonwood Chronicle

We were excited to be visited this week by Idaho’s State Archaeologist Ken Reid from the Idaho Historical Society. We hope all visitors have enjoyed their tours thus far.

The students revealed an interesting and exciting archaeological feature earlier this week. A feature is an arrangement of items or materials that in their shared spatial association, represent a cultural activity. Features can include things like pits, house foundations, organic stains in a site’s sediments, or dense piles of animal bone. Because these features represent particular activities, they are very important to the archaeologist. The feature discovered this week (known as Feature 3) appears as reddened sediments, caused by a chemical alteration (oxidation) of an ancient surface. We suspect that the creation of a large fire hearth, or a collection of smaller hearths, worked to alter the sediments, imparting the deep red color.

After the feature was discovered, students carefully worked to uncover the reddened sediments’ original surface and outlined the feature’s boundaries. Feature 3 is circular in shape and seems to have a slight depression at its center. Only a portion of Feature 3 lies within the excavated units, so it has an appearance of a half circle. The total station was used to capture spatial information about the feature’s surface by collecting readings in a grid pattern at 20 cm intervals.

Each flag marks a spot that was recorded by the total station. Notice the shape of Feature 3 as shown by the flags.

Once the spatial readings were collected, Loren Davis began recording the geochemical composition of each flagged spot using a portable x-ray fluorescence (XRF) meter, which is used to measure the chemical elements present within the site’s sediments. The data collected from the XRF meter can be used to compare the geochemistry of the reddened sediment within Feature 3 with the unaltered brown sediment outside of the feature, in order to make interpretations about the feature’s origins.

The XRF meter safely reads the geochemical composition of Feature 3

After the geochemical composition has been recorded for a particular part of the feature (marked by one of 185 different flags), students take a bulk sediment sample of that spot. The sample will be taken back to Oregon State University were a number of tests will be performed to determine its material composition.

A student takes a sample of Feature 3 sediment

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  1. By: Celeste Henrickson on July 27, 2010 at 6:38 pm      

    What an amazing feature! The pics are great. Thanks for the update.

  2. By: pansters on September 9, 2013 at 4:21 am      

    Do you use moisture meters to have more acurate results with xrf-handheld? I’ve seen that the results in dry and moisture ground are present.

  3. By: Loren Davis on February 12, 2014 at 11:19 am      

    Hello Luc,

    In response to your message posted last year, yes we do. We use a soil moisture meter made by Decagon.

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