The work begins

July 29th, 2016

1 Wangs Corner 072916Rochester, Minnesota — Today we started collecting specimens and data for the Team Minnesota student Independent Study projects. We began with a long drive south to Decorah, Iowa, to measure a thick section of our Upper Ordovician target units at the Decorah-Bruening Quarry (N 43.29036°, W 91.76558°), but a patch of persistent and heavy rain lingered over the area all morning. We gave up and headed back north to the Rochester, Minnesota, region, where it was dry and sunny. Our first stop was at Wangs Corner (N 44.41047°, W 92.98338°) to collect fossils from the Decorah Formation for a taxonomic and paleoecological assessment. Rachel Wetzel and Nikki Bell are the Team Paleontologists for this work.

Wangs signWangs is a little crossroads in this part of the Minnesota prairie. (Photo by Nick Wiesenberg.)

2 Dean on WangsDean Thomas has a role at this outcrop as well. He will be doing a conodont biostratigraphy and paleoenvironmental study of the Decorah and units above and below. At Wang’s Corner he found a thin biosparite bed in the midst of the calcareous shale that he can use to help stratigraphically position this section of the Decorah, which has no visible upper or lower contacts.

3 Wangs carbonate bedThis bed is a beautiful nearly pure, coarse, well-cemented biosparite/grainstone in contrast to the argillaceous beds above and below. The orange patches in the top of the rock are burrows (likely Thalassinoides) filled with sediment from above. The traditional interpretation of these units is that they were formed by storms. Why they are so clay-poor is a mystery.

4 Turkey Run 072916Our last stop was the Turkey Run locality (N 44.38441°, W 92.91199°). Here the Decorah Formation is just barely exposed through the weeds. The students gamely collected fossils as the bright sun made us forget the disappointing morning rain.

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