Team Jurassic Utah endures polar conditions

March 13th, 2019

Hurricane, Utah — Well, maybe not fully polar, but it was very cold and windy in southern Utah today. Our glove-less fingers were numb, and the bitter gusts penetrated our pitiful parkas. We collected some samples but put off measuring columns (which inevitably requires working fingers) for a warmer day.

Our mission, as before, was to find ooid-rich units for Anna and mollusk fossils for Evan. We were at the “Water Tank” locality (C/W-751) of last year. It is our least attractive site, having a blue water tower and all.

The bivalves here are numerous and diverse, but only in a narrow horizon (so far). They are certainly more species-rich than at yesterday’s Eagle Mountain Ranch site.Anna found a cross-bedded ooid-rich limestone along the road to the water tank. We will be back to measure and sample this section in detail.For lunch we went to nearby Snow Canyon State Park, where we hoped it would be a tad warmer. (It was — barely.) The sun was out and the colors vivid. This is the Petrified Dunes walk. All you see here is the glorious Navajo Sandstone (Jurassic — beneath the Temple Cap and Carmel Formations).I was entranced by the Moqui Marbles, a kind of iron oxide concretion that weathers out of the Navajo Sandstone. They accumulate in large numbers on the flat surfaces here.

Nick with Moqui Marbles eroded out of the Navajo.Here are Moqui Marbles in place in cross-beds of the Navajo. (Guess whose legs are the scale.) These concretions are diagenetic, forming in the sandstone long after deposition. You can read the latest ideas on their formation in this Moqui Marbles article.

The cold, cold group in Snow Canyon. Image by Shelley.

One Response to “Team Jurassic Utah endures polar conditions”

  1. Alex Crawfordon 26 Mar 2019 at 4:51 pm

    The average temperature in Hurricane in March is apparently a high of 66°F and a low of 38°F. So how far off of that were you? Those Moqui Marbles are super cool, by the way. I’ve seen them in the Navajo before, but I’ve never seen such a big accumulation as that group Nick posed with.

Trackback URI | Comments RSS

Leave a Reply