Another guest Friday fold… this one from my colleague Tiffany Rivera of Westminster College in Salt Lake City, Utah, the one who brought you yesterday’s thrombolite pictures…
Tiffany writes that these shots come from
a man-made boulder field / berm along the lake. The boulders were these beautifully folded gneisses. Antelope Island exposes some of the oldest rocks in the Salt Lake valley, but I don’t know the geology out there very well. I’d assume that the boulders were harvested on the island.
Here’s the good stuff:
Lovely! Thanks for sharing, Tiffany.
Happy Friday, everyone. I hope to see a lot of you next week at the fall meeting!
I’ve been hiking a lot in the hills near Salt Lake. This area is full of gneiss, but I am told it also has a lot of pegmatites. I’ve been reading up on both of them and looking at pictures online of them and they look the same to me. I understand that gneiss is a metamorphic rock while migmatite is igneous and metamorphic. Is there a way that one can identify them and tell them apart with the naked eye?