Ripple marks

… And here are some ripple marks from a block of the same sandstone in the previous image.

Nice! Hope everyone is doing well. Lots of good geological experiences to report on, buy it’s hard to write a substantive blog post from phone… You’ll have to wait until I’m back at a computer!

Mudcracks

Here’s a package of mudcracks from a block of riprap on the waterfront of Burlington, Vermont:

Oh yeah….

Gros Ventre landslide, Wyoming

Yesterday’s field work took us to this classic mass wasting site:

Grand Teton

It’s late afternoon in Jackson Hole, with the sun dipping down behind the Tetons. I’m waiting for some students to finish up their hike in Cascade Canyon and ferry back across Jenny Lake. Here’s a snapshot of the moment:

Stack of field notebooks

Dashboard decor…

Van flag

The students had placed this flag on te van antenna when I came out this morning… The other side says “it’s too gneiss!”

Folded Archean gneiss

Here’s a nice sample of folded gneissic banding in basement complex of the Gallatin Range, Montana. According to Dave Mogk of Montana State University (who I met in person for the first time on Saturday), these high grade metamorphic rocks are as old as 3.2 Ga (billion years old). They experienced temperatures as high as 750 degrees C, and pressures equivalent to 25 kilometers of depth in the crust. The lovely folds were what caught my eye, however:

Happy Tuesday!

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