For my historical geology lab, we took a field trip to Midwestern Utah. I have way too many photos and experiences to share, so I decided to divide the trip into different sites. I'll start with Notch Peak.Seen in the photo above, Notch Peak is the highest peak in the photo. Notch Peak is formed by the Weeks formation, overlain by the Notch Peak formation, both Cambrian in age.
A Jurassic granitic intrusion caused contact metamorphism of the Weeks formation (basal layers of Notch Peak) and Lake Bonneville deposits make up the basin sediment.
The contact metamorphism was the highlight of this site. That's my instructor, Forest Gahn. (Can you spot the rock hammer on the outcrop?)
BYU Idaho students seated on the outcrop during the discussion, the altered Week's formation, capped by Jurassic "granite" (jointed diktytaxitic quartz monzonite), with Notch Peak dominating the skyline.
The photo below shows a xenolith of the altered Week's formation included in the granitic rock. It also shows the detail of the altered Week's formation. Notice the interfingering of the lighter calcitic layers and the darker silicic layers and the garnets that have formed in the calcitic layers. This is an impressive outcrop -a great example of contact metamorphism.
That's the start of my "digital unloading". I'll be posting more as I find time to do it. In the mean-time, I've got to pack for my trip to southern Utah and the Grand Canyon.
