Mineral Monday: Stibnite in a Piece of Core

Just a bit of stibnite for your #MineralMonday.

From the Road: Whipple Mountains

Savahia Peak in the Whipple Mountains, with cholla.

And here's a cartoon of the geology.

The upper plate volcanic rocks are dipping moderately to steeply to the west (cyan bedding). The Whipple Mountains detachment fault (hachured dark blue) is fairly flat-lying in this area, separating reddish, hematitic upper plate rocks from greenish, lower plate chloritic and mylonitic gneisses. I've drawn in a few approximately located listric normal faults in bright blue to illustrate the general structural configuration. The upper plate has moved to the east relative to the lower plate, as indicated by both the dip of beds in the upper plate, and (especially) by the movement on upper plate listric normal faults.

From the Road: Mountains Partly Covered with Sand

I stopped along the way to check out some run-down and decrepit old buildings in the valley near Twentynine Palms (the valley of Dale Lake, a dry lake or playa, sometimes called "Wonder Valley"), and came upon an area where not only were the mountains being choked and overrun by their own alluvium, they were also being buried by pinkish orange sand blowing in from the western Mojave. This is the southern Sheep Hole Mountains near the western approach to Clarks Pass. The pinkish orange color is from the abundance of K-feldspar often pink to pale orange in color) in the sand.

From the Road: Mt. Whitney

Here's a quick pic of Mt. Whitney and a little bit of the Alabama Hills. Whitney is the bright rocky peak (or maybe you could just call it a large rock) behind the shadowed mountain, a little left of center. The Alabama Hills are the brown, granitic hills in the middle ground. Lots of movies have been shot at least partly in this area (Wikipedia lists some; IMDB lists many, but the list may includes Lone Pine itself).

From the Road: Conway Summit

I'm having a little trouble keeping up with the road trip--for one thing, the mobile app thingy doesn't really work very well, so it's easier to just wait until I have wifi, and I don't get any of that when camping (!)--but here are two photos from Conway Summit.

The first looks south at Mono Lake. The Sierra Nevada is on the right, and the White Mountains are on the far left (they don't look impressive in this photo, but they are). The Mono-Inyo Craters, with the caldera rim of the Long Valley Caldera beyond it (they are indistinguishable in this photo) form the hills that provide a nice backdrop to Mono Lake. You can barely see Paoha Island in this photo; it's the light-colored island behind the dark land mass left of center. The dark land mass is Black Point, a 13,300 year old basaltic cone. Negit Island is easy to see: it's the smallish, dark-colored band to the left of Paoha and Black Point. Paoha and Negit are both volcanic islands, although it looks like the lake is low enough that Negit is not currently an island. The lake looks really low--I thought they were maintaining it at a higher level; maybe it's the drought, maybe the water accord has failed.

The roadcut across from the Conway Summit pullout (just below Conway Summit, actually) exposes grusy, unglaciated granite. There's also quite an exposure of glacial till in the hill above the granite, and in the hill and roadcut leading up to the summit proper, which you can see when driving north or south on 395.