July 31, 2006 - We get a rainbow |
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July 31, 2006 - We get a rainbow |
Maggie_Kane |
Jul 31 2006, 08:44 PM
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Advanced Member Group: TREC Team Posts: 51 Joined: 12-April 06 Member No.: 27 |
Do you like to collect rocks? Seaglass? Shells? Well, today I collected a few really interesting shells from the Linne Valley. I had been walking over them for days and had heard the interesting story about how these shells (Hiatella arctica) got so far from the sea. Do you remember an entry about 2 weeks ago about raised marine terraces along the sides of the valley? Well, those terraces are old beaches, and the sea used to extend into the valley thousands of years ago. The shells that we see now are remnants from that sea. Last year, Mike Retelle and others dated the shells to be about 10,000 years old.
Shells - Hiatella arctica Most of the soils in the valley get moved in a kind of very slow boiling motion. This is a response to freezing and thawing of the active layer of the ground, where rocks come to the surface and get sorted out by gravity as the center domes upward in the spring. Some rocks get broken by freezing and thawing, leaving strange and beautiful patterns of jagged rocks across the landscape. These are all over the valley and this process may have helped some of these shells come to the surface. The patterns take many forms; sometimes the center of a pattern is very soft and jiggly, and sometimes it is made of small to medium sized blocky rocks. Generally, the larger rocks have been moved out to the edges defining the circle, and if they are white, they make stunning shapes. Heidi Enjoying the Patterned Ground The patterns links together to form whole fields, like swarms of misshapen circles. They are really beautiful, and always a pleasure to see in the field. There are several types of rocks in Linne Valley, and the sorted polygons look different where different rocks outcrop. More Patterns Today was a bit wet, with drizzle and fog and we were blessed with a beautiful rainbow on our return hike from the lake. The light came through the clouds after being heavily obscured all day, and sent the colors into a tailspin! Rainbow Over Linnevatnet The students are working hard to get a good hold on their projects and will be able to start presenting some ideas to the group starting tomorrow. They spend a lot of time working with their data, reading research papers, manipulating images and graphs and talking to each other about their work. Sometimes they get sick of me taking pictures of them and ham it up! Studying! This magical place is different every day. We are so incredibly lucky to be here, to see it and walk through it each day and discover new things. We also are enjoying being together, and get playful no matter the weather. The time is just flying by and we are drinking in the experience as best we can. It's Fun No Matter the Weather! |
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