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Valley of Fire State Park, Nevada, 2020.
Ha I know where this is relative to the campsite (was there this year). Something interesting? There’s a big thrust fault literally at the base of that pile of red rocks in the center of the image. It’s almost completely flat.
Take a trip to an intracontinental triple junction - the boundary between the Basin & Range, Mojave, and Colorado Plateau provinces in the southwestern US.
Red Rock Canyon by Dan Gildor
Via Flickr
I’d been hearing of Red Rock Canyon the last few times I’ve been to Vegas as an option for outdoor activities. With a late flight and a car rental, I figured it was time to check it out.
No camping by Dan Gildor
Via Flickr
Overall, Red Rock Canyon doesn’t have that much red rock nor is it much of a canyon.
Moody afternoon views from Rainbow Mountain Peak, RRCNP, NV
Oops, we made a geyser!
Geysers are a pretty rare phenomenon—they require a unique set of conditions and only occur naturally in a few select places around the world. However, mankind has created some geysers of our own…and usually it’s on accident. Exhibit A is Crystal Geyser in Utah (shown erupting out of a pipe in its photo). An oil well was drilled here was in 1931. The well didn’t produce any oil, but it did create a new way for bubbly water to escape. The groundwater here has a high concentration of dissolved CO2, and since the well was never capped, a “geyser” was born. Crystal geyser is unique in another way—the water is cold and its eruption is only due to CO2, not hydrothermal activity.
At its peak, Crystal Geyser erupted plumes up to 100 feet high (30 m). In recent years, the activity has slowed. Impatient tourists often drop rocks down the pipe in attempt to trigger an eruption, which has clogged the plumbing. .
Another example is Fly Geyser in Nevada (shown erupting out of a cone). Fly Geyser has a similar origin to Crystal; a well was drilled for another purpose, and in this case that well accidentally tapped into VERY hot, pressurized water. Interestingly enough, this well WAS capped, but the water got out anyway.
Both geysers carry mineral-rich water, which precipitates into the quite beautiful travertine terraces and cones shown here.
-CM
Photo credit: Crystal Geyser: http://bit.ly/1a62J3y
Fly Geyser: Tanya Wheeler http://bit.ly/1CVqeXy
Meet Dioptase for this mineral monday
Remember the Alamo (Impact)
One of the best impact craters around is the Alamo Impact, a Devonian structure found in Nevada, not far from Las Vegas. One of the best AND worst things about it is the sliced-and-diced nature of its evidence. Basin and Range tectonics has done a number on it, but its dissected nature makes the inner anatomy easy to see. A recent paper by Retzler et al. (see http://geosphere.gsapubs.org/content/11/1/123.abstract) has now revised the craters width at up to 150 km, making it bigger than the more recent and well-known Chesapeake Bay impact site (see our post https://www.facebook.com/TheEarthStory/posts/785481198179593).
Another thing that makes this impact unique is how you find it. It was not found by a circular structure, but instead by impact breccia deposits found in normal marine settings. The picture, by Mark Wilson, shows this quite nicely.
-MrA
The Great Basin's Great Rock Art.
"The Great Basin," the explorer John C. Fremont said, is that "intermediate region between the Rocky Mountains and the next range [the Sierra Nevada], containing many lakes with their own system of rivers and creeks...and which have no connection with ocean, or the great rivers which flow into it." Perhaps the most striking feature of the Great Basin are its many north-south-trending mountain ranges and intervening broad valleys. Many of these ranges are massive. Thirty-three have elevations exceeding 10,000ft and even valleys between these ranges stand at high altitudes. It has been explored in great detail and we have learnt a remarkable amount about how the region came to be the way it is today. Most directly relevant to the basin's human history are it's last 12,000 years of its early inhabitants and how they lived in its distant past.
Rock art is a familiar but enigmatic trace of ancient people in much of the Great Basin, one that fascinates those who see it and sparks much debate amongst scholars. Native people in the Great Basin made rock art and incorporated it into their social practices perhaps as long as 10,000 years. Their art included visually arresting figures and motifs such as naturalistic depictions of bighorn sheep apparently being hunted.
Such images appeal to modern eyes because they seem to show actual scenes of daily life. Other figures and motifs are more mysterious to viewers today. However we interpret it, rock art remains in the place where its makers intended for people to see and interact with. For this reason, few viewers can escape a sense of place and the sweep of human history when looking at rock art in its natural setting.
What do the enigmatic rock art panels, motifs, and figures mean, and why did people make them? One answer is that ancient people were trying to enlist magical aid to ensure success in the hunt, increase the numbers of game animals and other resources, or symbolically manage prized or feared animals. In the 1960’s Robert Heizer and Martin Baumhoff adopted this theory known as the hunting-magic theory for Great Basin rock art. In this view, representations of bighorn sheep and deer portray the game of animals that hunters most desired. By making pictures of the animals, hunters could exert some kind of magical control over them.
They also noted that many Great Basin rock art sites lie along game trails, in good places for ambushes, and near hunting-related features such as hunting blinds and projectile points. One problem with the hunting-magic explanation is that it cannot account for many rock art sites that have no animals or hunting scenes and other scholars have offered alternative explanations. David Lewis Williams and Jean Clottes's related the art to stages of hallucinatory experience and shamanic practice based interpretation suggesting that the art was done in ripened states of being and was a direct magical connection to the other world perceived in these states.
In the western Great basin, abstract Basin and Range Tradition motifs dominate most sites, and in the eastern part anthropomorphs are most prominent. Also, many rock art sites are near the remains of domestic camps –house rings and tools used for processing plants and seeds –which implies that women as well as men made and used rock art.
~JM
Photo Image: My own that I took in the Valley of Fire, Nevada.
Further Reading: Prehistoric Rock Art of Nevada and Eastern California.Robert F. Heizer and Martin A. Baumhoff. Berkeley: University of California Press. 1976. 412 pp. The Nevada Rock Art Foundation:http://www.nvrockart.org/ Southern Nevada Rock Art Association:http://www.snraa.org/snraa.org/Home.html Live Science: http://www.livescience.com/38865-oldest-petroglyphs-rock-art.html Valley of Fire: http://parks.nv.gov/parks/valley-of-fire-state-park/
majeczkyvisuals
It’s only spring but it sure feels like summer out there! This time of year you can get the whole beach to yourself! Model:
@drcadyshack
Conk opal While not really suitable for jewellery use due to its tendency to crack as it dries out (called crazing in the trade), this rare opal from the Virgin Valley of Nevada displays some intriguing characteristics. Some 14 million years back, a volcanic eruption of silica rich magma filled an ancient lake and its surrounding forests with a thick layer of ash. Groundwater then dissolved some of the silica leaving clay minerals behind and redistributed it as the lake was buried in further sediments and heated up. The precious spheres of SiO2 precipitated into cavities within wood that were originally formed by fungal diseases rotting holes into the lignin. The beautiful piece in the photo won best of show at Tucson in 1990, and measures 10cm long by 6 wide. Loz http://royalpeacock.com/fee-digging/about-our-opals http://www.jckonline.com/article/289690-Virgin_Valley_Opalized_Wood.php
Valley of Fire
These rocks are cross-bedded sandstones of the Aztec formation found in Valley of Fire State Park in Nevada.
This unit correlates in time with the Navajo Sandstone found in other parks throughout the Western U.S. The patterns of layers and cross bedding are similar to patterns we see forming in sand dunes today, implying that the rocks formed in giant sand dunes. In the early Jurassic when these rocks formed, this part of the North American continent was basically a giant sand sea known as an erg. The climate of the area gradually moistened during the Jurassic, allowing for preservation of these features. The colors are produced by iron oxides that were trapped in the sand dunes as they formed.
-JBB
