Photographs from the past few months

The north end of the Salton Trough in the Coachella Valley. San Jacinto Mountains in the background, center. The Indio Hills - San Andreas Fault are barely visible in the valley.


Badlands of the Painted Desert in Northeast Arizona


The famous El Capitan, Permian reef structure. Brian Romans of Clastic Detritus has much more information about this place.


The foredune crest, of the barrier island, Padre Island.

Lot more photographs.

Even more photographs

Stoney Indian Pass in Glacier National Park. Various glacier landforms.

Split Mountain, an anticline in Dinosaur NM. Take a look at the gigapan from Ron Schott for a different view and better geology write-up.

Labyrinth Canyon of the Green River in Canyonlands NP.

Brontosaur tracks at Picket Wire Canyon in SE Colorado.

Valle Grane, part of the larger Valles Caldera in N New Mexico.

Riparian forest, floodplain, terrace of Gila River in Gila Box in eastern Arizona.

More Photographs

More photos from the field...

An addition to my previous post.

John Day Fossil Beds in central Oregon


Volcanic deposits in North Fork Toutle River, near Mt St Helens.


Western section of Dry Falls, a waterfall formed during the Missoula Floods.

More photographs

I'm not dead yet

Really.

So rather than be an unemployed geoscience type this summer, I decided to be a an unemployed geoscience type that travels. So for the last two months, I have been backpacking in various places in the western US. Here are a few geology influenced pictures.

Cirques, tarns, moraines, and an active rockfall (notice dust cloud on mountain on the left) in John Muir Wilderness, Sierra Mountains.

Sag Pond on San Andreas Fault at the south end of the Carrizo Plain.

Point Reyes headlands.

Lava tube at Lava Beds National Monument.

Not Spring

Ruby Valley, NV

Spring

Desert Lake and Dune Field

Desert lake and Sand Dune Field from Google Earth.

Last weekend I took a trip to Desert Lake located in the Desert National Wildlife Refuge. The lake is a large dry playa located in Desert Valley, an endorheic basin. An endorheic basin, also known as a closed basin, has no water exiting or leaving it. The valley itself is located on the southern side of the larger endorheic Great Basin. Because of the unique names of the playa and valley, I haven't been able to find much published literature about the area.

Desert Valley drains an area starting at the Groom and Tikaboo ranges near Rachel, through Nellis Air Force Range, before terminating at Desert Lake.

Although it was wetter in the area during the Pleistocene and may well have sustained a permanent lake, now the area receives less than 15 cm of rainfall a year. The frequency of induation of this playa, like most playas, is probably unknown (Lichvar et al. 2004)

Desert Lake as seen from the dune field looking toward the southwest

There are lots of playas in southern Nevada, but desert is more unique because of its associated sand dunes. To the east of the lake is the Sheep Range, a 1,500-2,000 m mountain range of Cambrian to Devonian dolmite and limestone (Jayko, 2007). Along with predominately westerly winds, this allows the formation of a dune field.

The Sheep Range from just north of Desert Lake

This process is also illustrated on the larger and more famous Great Sand Dunes National Park. As seen in this image from the park's website, winds blow the deposited sand west until it is again deposited at the base of the mountains. Winds blowing through mountains passes from the east help to pile the sand into dunes. For much more information about the Great Sand Dunes see a recent paper in Geomorphology (Madole et al., 2008).

Desert Lake Sand Dune Field

I estimated the tallest dunes as > 20 m. The Dune Field covers only a few square km of land, however, the surrounding area is quite sand, but is mostly covered in vegetation. The dunes themselves are only sparsely vegetated with Ambrosia eriocentra (woolly bursage) and Chilopsis linearis (desert willow). The dune field is one of the northernmost natural occurses of C. linearis (Ackerman, 2003).

Chilopsis linearis

Finally, just for fun, here is a shot of some ripples on the dunes and check out geology.aboout.com's recent visit to the Kelso Dunes in California.

References:
Ackerman, T. L. 2003. A Flora of the Desert National Wildlife Range, Nevada. Mentzelia 7:1-89.

Jayko, A. S. 2007. Geologic Map of the Pahranagat Range 30' × 60' Quadrangle, Lincoln and Nye Counties, Nevada. US Geological Survey.

Lichvar, R., Gustina, G., Bolus, R. 2004. Ponding duration, ponding frequency, and field indicators: A case study on three California, USA, playas. Wetlands 24:406–413.

Madole, R. F., Romig, J. H., Aleinikoff, J. N., VanStistine, D. P., Yacob, E. Y. 2008. On the origin and age of the Great Sand Dunes, Colorado. Geomorphology 99:99-119.

Fun with a camera and a scope

My workplace has a very nice Leica Televid 77mm birding scope, so I decided to try my hand at some photographs using the scope. It was a lot harder than I thought! My best photograph was of a Brewer's blackbird on top of a telephone pool.

My shots of a group of American coot didn't turn out so well...

Finally, a night shot of a controlled burn on the refuge and an anti-Southern Nevada Water Authority display from near Baker, NV.

Obed River 2

Taking a break from thesis writing, I took a short hike over at Obed River. I had been there before, but it is a nice place, free of the traffic that plagues other places. With the leaves off the trees I got a few nice shots of the gorge. The rock here is basically flat lying sandstones, so nothing to fancy in terms of geology. I was rather surprised to see some logging almost up to the cliff themselves (notice the slash pile in photograph two), but since this isn't a national park or wilderness area, that kinda of stuff is allowed. An air photo from the area shows how close it already was. Technically, all these shots are of the cliffs over Clear Creek. I once again tried to do a panorama with hugin on the last image (photo 2 is showing the upper right of photo 3).

Angel Falls Overlook

It had been over a year since I last went to Big South Fork so I thought I would go back. The geology of the area is nearly horizontal laying Mississippian and Pennsylvanian aged sandstones and shales. The Cumberland Plateau's topograph in the area is relatively flat, but becomes quite steep and rugged in streams and rivers valleys. Not only has the Big South Fork of the Cumberland River has cut a deep valley, but even small streams quickly cut down (a sample topomap shows this clearly). This results in the largest natural arches in the eastern US, rock-shelters, and cliffs. The first image is of the Angel Falls overlook from a ridge to the west. The next two images are of the Big South Fork from Angel Falls overlook, the third one is a panorama made with hugin). The last one is a site with some interesting weathering.

There is interesting ecology present too. Drier sites are a mixture of White Pine (Pinus strobus), Pitch Pine (Pinus rigida), Virginia Pine (Pinus virginiana), White Oak (Quercus alba), Scarlet Oak (Quercus coccinea), and under-stories of Mountain Laurel (Kalmia latifolia) as shown in the first image. The second image shows a tough Virginia Pine hanging on a cliff and the third a photogenic Common Buckeye butterfly (Junonia coenia).

Finally, the park has many signs of past human activities, from Native American to European settlers to industrial logging and coal mining. The last image shows the house and English-style barn built around 1900 by John Litton.

Big Fodderstack

Last year on November 4, I went to Little Fodderstack in Cherokee National Forest. I thought this November 3 I would go see its neighbor, Big Fodderstack. This fall has been much warmer and drier so I didn't know what to expect. Both of these images are of Brush Mountain, from different sides. Big Fodderstack is visible in the background of the first one.

After spending so much time in wet, cool, and dark cove forests doing my thesis field work, I enjoy going to open oak-pine forest. There was a nice variation in forest composition, based on altitude and location on the ridge. Near the valleys, there were numerous Chestnut Oak (Quercus prinus) and White Pine (Pinus strobus). On closer inspected, I noticed a few Shortleaf pine (Pinus echinata), although most were dead or dying as the more shade tolerant White pine finally made it to the canopy. Further up the ridge, Virginia Pine (Pinus virginiana) dominated, although they too were being replaced. There were also a great number of Black Oak (Quercus velutina), a species I am not very acquainted with. The understory was dominated by Sourwood (Oxydendrum arboreum) which was flame red in color. I was also surprised by the large quantity of American Chestnut (Castanea dentata) sprouts, some up to 20 ft.

The trail doesn't go all the way to the top of Fodderstack, although a bushwhack pretty easily gets you there. It is marked by a cairn and a USGS benchmark.