5-21-15

A very large Joshua tree ( Yucca brevifola ) in the Mojave National Reserve, California. They don't usually have this many branches! The shrubs around it with the small dark yellowish-green leaves are creosote bush, another characteristic component of the Mojave floral assemblage. Joshua trees are supposed to have gotten their name from Mormon emigrants, who thought they looked like the prophet Joshua beckoning them onward. If Hollywood had filmed more Westerns in the Mojave back in the day, the Joshua tree, rather than the saguaro, might be an icon of the American West. As it is, they are prominent in the opening scenes of _The Right Stuff_, where Chuck Yeager was knocked off his horse by one. Edwards Air Force Base is in the Mojave and Joshua trees are locally abundant around it, so that's not poetic license! Map location is approximate.

With the Providence Mountains beyond. Looking northeast--this is sunset lighting. The Providence Mountains are capped by sedimentary rock, including much limestone, and there's even a small limestone cavern there ("Mitchell Caverns"). At one point it was a California state park, but last I heard it--alas--was a casualty of budget cuts. The Providence Mountains stand high enough--~7K ft/2134 m--that they catch significantly more rainfall than the surrounding desert. This feeds an aquifer in the valley below, as well as supporting a scrub piñon/juniper forest in a so-called "sky island". Back in the days of steam engines, the aquifer provided plenty of water for the locomotives, which would refill at the tiny (and now almost abandoned) railroad town of Kelso, barely visible at extreme left (note). Mojave National Reserve, California.

A dune field in the Mojave National Preserve, California, in the middle of the Mojave Desert. It's about 10 miles from the tiny (and nearly extinct) railroad town of Kelso on the Union Pacific Railroad. The area is all wilderness now, so is off-limits to dune buggies and the like.

On partly stabilized sand dunes, Mojave Desert, California, looking south from just off the right-of-way of the Union Pacific Railroad. Kind of a stressed environment--

In young, barely consolidated conglomerates. South side of Afton Canyon, Mojave Desert, Caifornia. They look inviting to explore, but I didn't have time--

Mojave National Preserve, Mojave Desert, California.

My tracks down a slip face at the Kelso Dunes, in the Mojave National Preserve, California. This is a "singing" (or "booming") dune--as you slide down the face, you hear a deep tone from the sand. It's astonishingly musical for such improbable materials, like a low note on a cello. To "sing" evidently the dune sand has to be very dry and well sorted--i.e., all the grains about the same shape and size. (It won't sing after a thunderstorm!) The phenomenon is more than a little eerie, especially when you're out there by yourself. You can see why the stories in the _Arabian Nights_ and so on attributed the singing to djinns or other spirits!

Along the (usually) dry Mojave River in the middle of the Mojave Desert, California, on its route between Los Angeles and Las Vegas. This was the original route between L.A. and Salt Lake City, built in 1905. Las Vegas as a city owes its founding to construction of the railroad; the railroad located a settlement there because of a large spring ("las vegas" = "the meadows" in Spanish), and the city now celebrates this as its founding. For the first couple of decades of existence Vegas was a little railroad town--only the construction of nearby Hoover (Boulder) Dam in the 1930s started its explosive growth in the 20th century. The Mojave rises in the San Bernardino Mountains east of L.A. and flows northeast out into the desert. The canyon is of disproportionate importance to wildlife because the shallow bedrock locally forces water to the surface. Vehicle traffic thru the canyon is now effectively blocked because of several deep fords--even with my Jeep I didn't try them!