1967 Excavation of the Two Creeks Interglacial Soil Horizon
Much has been written about the Two Creeks interglacial soil horizon in northern Wisconsin. This article will not attempt to repeat any of the geological information.
Instead, this shows a few photographs that I took in August of 1967 at the site that is now the Two Creeks Buried Forest State Natural Area . Dr. Robert Black of the University of Wisconsin-Madison (UW) and Dr. Thomas Hendrix of Indiana University (IU) were co-principal investigators for a research project to expose a small part of the buried soil horizon. A primary purpose of the project was to make a film to show some of the techniques that soil scientists and geologists use in the field. Joining the two faculty members were five students, three from UW and two from IU, one of whom was me. Also, UW provided audio-video equipment and technicians. Unfortunately, with the passing of 50 years, I have forgotten the names of the student participants and the film crew.
The images below were scanned from my old photographs. The camera was a Kodak Instamatic, and the prints were faded. The scans were brightened up with the color restore feature of the scanning software.
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Most of the field party camped at the Point Beach State Park. The field site was just a few miles north of the state park. |
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As mentioned in the introduction, an objective of the project was to film field operations. A small bench was dug into the face in which the buried horizon is exposed. You get a hint of the soil horizon in this photo. It is the black spots in the face that begin near the lower right corner of the image. A platform was built on the bench so that the caster-equipped tripod that carried the camera and audio equipment could be easily moved. The fellow in the foreground is my classmate from IU. The other three are the UW students. In the background, you can see the shoreline trend eastward toward Point Beach south of the site. This is, obviously, a morning shot. After midday, the face is shaded, and photographs of the soil horizon in the cliff are not as striking. |
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The bench in the image above was dug by hand with shovels. The initial actual geological work was to scrape the face of the cliff to remove recent slumpage in order to expose undisturbed layers. The A-horizon of the Two Creeks soil is clearly seen here as the black stripe. |
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Once the cliff face was clean, the soil scientists collected vertical columns through the soil and the other layers using a tray sampler. In this picture, you can see how a vertical rectangle has been outlined with a small tool, like a trowel. The metal sample tray would be inserted into the carved rectangle. Then, the sample would be freed and captured into the tray using the spade, the blade of which is visible in the upper right corner of the image. The tray and sample were subsequently delivered to the lab at UW for detailed study. |
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We worked on the face for a few days. We “staged” a few scenes for the film crew, but the scenes were really amateurish. Then, the serious work began. A backhoe was brought in to remove most of the overburden above the buried soil. We had studied the soil and the layers of till above and below it in the vertical “plane”. Next, we wanted to see the soil and the other horizons in the third dimension, i.e., more or less, the horizontal direction. The backhoe removed a lot of the overburden, but we were back to using shovels to remove the last foot or two of material above our targets. |
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As we got close to the horizons of interest, the shovels gave way to trowels. Here, Professor Hendrix is exposing a branch using a common mason's trowel. As the soil horizon was exposed, it looked just like a modern forest floor with branches, stumps, needles, cones, and even some snail shells. The linear shadows on the ground are from the framing in the roof of the shelter that was being built over the excavation. |
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Here is another view of a root or a branch or maybe even a fallen trunk. The vertical dark thing in the upper left corner is a pole. As mentioned in the caption above, we were in the process of building a shelter over the excavation so that the site would be protected from the elements and remain available for viewing by other scientists. |
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This is a stump that extends out of the soil, the black stuff, and was surrounded by the clay and silt that covered the ancient forest. The bright circular object is probably a nickel or a quarter and gives you a sense of the size of the stump. Though approximately 12,000 years old, this stump looked like one in a modern forest. |
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As our three week field session drew to a close, Professors Black (with the saw) and Hendrix (in the blue hat) treated us to watermelon. While many of the geologists carried a pocket knife, no one had a knife big enough to cut a watermelon. As mentioned above, we were building a pole barn-style of shelter, the framing for which you can see in the background. The hand saw was readily available and seemed to be quite satisfactory for preparing the watermelon. |
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That is me sitting in front of the sign and eating a slice of watermelon. By this time in the project, most of our energy was going into completing the shelter. |
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This is what the shelter looked like when we were done. It looked pretty nice for the work of amateur carpenters. I heard that a storm blew it down a year or two later. I believe that the shelter was open to the lake side of the structure. |
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6-14-2017