Jackson Peak section: Another gnatty adventure

This morning the Wooster Geologists visited the westernmost exposure of the lower Carmel Formation at Nielson’s (1990) Jackson Peak section. Nick and Vicky are shown above on the road towards the conical Jackson Peak in the background. The site was as buggy as any other on this trip, with not a breath of wind to relieve us.

Nick took this image of our team hiking up a wadi in search of a good place to make a stratigraphic column. Jackson Peak looms in the background.

We established the base of the section in a wadi at N 37.327356°, W 113.858144°. Because of the rough terrain, the gnats, and the mostly-covered nature of the stratigraphy here, we decided to use Nielson’s (1990) original measurements and then sample along his column. Note that burned trees give very little shade.

Another image by Nick of Wooster Geologists at work. In the background is Square Top Mountain, which is most notable as the site of a B-52G crash in 1983.

This is the highest in-place outcropping of the typical lower Carmel Formation stromatolitic micrite beds. You can see the fine microbial layering on the weathered surfaces of the rock. Sampled as JP-1.

Like an old friend, the distinctive sandstone we saw in the Manganese Wash section showed up here at Jackson Peak. It has the same weathering appearance and, at the handlens level, the same lithological composition. Sampled as JP-2.

Unlike at the Manganese Wash section, the sandstone at Jackson Peak has an ooid shoal biosparite/grainstone directly above it, our sample JP-3.

This ooid shoal deposit as the same low-angle cross-bedding and current ripple marks as we’ve seen in all our Carmel Formation sections.

At the top of the ridge we were studying, Lucie and Vicky came across our second rattlesnake of the trip. It buzzed immediately, so Lucie and Vicky moved away quickly. Nick got this great image.

On our way back from the Jackson Peak section we met two Bureau of Land Management officers on horseback. Now there’s a cool job. (Photo by Nick.)

As is our tradition on these southwestern Utah expeditions, after we finished our work at Jackson Peak, we visited the 1857 Mountain Meadows Massacre site a few miles to the north.

This is the cairn marking the mass grave of 34 of the victims buried on the massacre site. It is a sad and enraging story we encourage you to read at the link above.

About Mark Wilson

Mark Wilson is a Professor of Geology at The College of Wooster. He specializes in invertebrate paleontology, carbonate sedimentology, and stratigraphy. He also is an expert on pseudoscience, especially creationism.
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