The name “Mexican Hat” comes from a curiously sombrero-shaped, 60-foot wide by 12-foot thick, rock outcropping on the northeast edge of town. The “Hat”‘ has two rock climbing routes ascending it. It has frequently been noted on lists of unusual place names.
Steeply dipping strata define the western edge of the San Juan basin. To the west older geologic formations are exposed toward the Defiance uplift whereas basinward they are they are downwarped thousands of feet beneath younger rock units. Vast coal, uranium, oil and gas resources occur in the strata buried within the basin.
Grove Karl Gilbert (1843-1918) is considered one of the greatest American geologists, having pioneered many theories in the earth sciences. In the late 1800s and early 1900s, Gilbert advanced concepts of mountain building, fault scarps, earthquake probabilities, and lake cycles that have withstood the test of time and are still used today. Furthermore, Gilbert applied science toward promoting public welfare by advocating the need for evaluation of risks and public disclosure of geologic hazards.
Utah was one of Gilbert’s favorite study areas where he formulated many of his theories. He spent much time at this particular location and was the first to establish that Little Cottonwood Canyon and Bells Canyon glaciers descended as far as the shoreline of ancient Lake Bonneville. Gilbert was also the first person to recognize the earthquake hazard posed by the Wasatch fault.
As you stand here look around, the magnificent cliffs, canyons, knobs, and spires before you are mostly cut from the 190 million-year-old Navajo Sandstone formation. Imagine the winds that carried sand to this area and deposited it in sand dunes hundreds of feet high. As wind shifted the massive sand dunes, the sands were deposited in a whirl of layers. Buried over eons of geologic time, the sands ceased their movement and turned to stone. Water releases the grains of sand from the grip of stone. Even here in an arid climate, water is the prime agent sculpting the stone into canyons, arches, and pinnacles. You are near the center of the great anticline that is the San Rafael Swell. Here, the layers are nearly flat-lying. It is like a stone dome with the curved top worn away. Soon the layers will begin tilting gently to the west.
Church Rock is a solitary column of sandstone in southern Utah along the eastern side of U.S. Route 191, near the entrance to the Needles District of Canyonlands National Park.
With majestic Colorado and Green River canyons, Canyonlands, this 200 foot roadside oddity near Monticello is called Church Rock. It seldom attracts more than a casual glance as visitors head toward Newspaper Rock State Historic Monument and the Needles district or drive between Moab and Monticello.
One of the interesting pages of 1930’s myths tells about Church Rock, and how the gumdrop shaped rock earned its name. The story is that Marie Ogden’s Home of the Truth, an Utopian community, was erroneously responsible. Ogden was a spiritualist during the 20’s, giving lectures across the U.S. on spiritualism, until she came to San Juan County, Utah. She allegedly called San Juan County and Church Rock “the spiritual center of the universe.” With a small band of followers, Ogden’s group moved onto a tract of barren land along Utah’s Route 211 in 1933, calling it the “Home of Truth.” Members turned all their worldly goods to Ogden to join her Home of Truth, abiding by a strict code of conduct, were expected to work for the common goals of the settlement. Women tended to the domestic chores and men worked the arid farm acreage. Not far from Church Rock are the remains of Ogden’s ghost town. A few buildings and a small cemetery are all that remain of the Home of the Truth community, found on a ridge called Photograph Gap. After the community broke up, Ogden stayed in Monticello and became the owner and publisher of the community newspaper, The San Juan Record, in the 1940s. She died in the 1975 and is buried in Blanding.
The three-tiered sandstone rock is located not far from the Home of Truth, but is only one of several in the area (Sugarloaf and Turtle Rock among others). Part of the myth is that the group set upon a grand plan to hollow out the entire center of the sandstone monument, by hand, to build a church. In fact, the sandstone formation was owned by a local rancher, Claud Young of Monticello. Young owned about 2000 acres of land, for cattle range, before the highway came through the area known as Dry Valley.
The only evidence of the myth, and the apparent basis for the assumption of turning the rock into a ‘church,’ is the 16 by 24 foot opening chiseled into the rock. In fact, that ‘opening’ was contracted out by the owner, Claud Young. The opening was dynamited and cut out of the stone during the late 1940s to store salt licks and feed for the cattle. The rock is still owned by the Young family, in equal shares by the two daughters and two sons of Claud and Inez Young, their surviving spouses, and/or surviving grandchildren owning their percentage of ‘the rock.'(*)
The Wetumpka Impact Crater is the only confirmed meteorite crater in Alabama, United States. It is located east of downtown Wetumpka in Elmore County, Alabama. The crater is 7.6 km in diameter and its age is estimated to be about 83 million years (Cretaceous) old based on fossils found in the youngest disturbed deposits, which belong to the Mooreville Chalk. The crater is well preserved, including the original impact rim and breccia, but exposures are few owing to plant and soil cover, and nearly all are on private land. Thornton L. Neathery discovered the Wetumpka Crater in 1969-70 during regional geological mapping and published the first article on the subject in 1976. However, conclusive evidence of impact origin was lacking until 1998 when David T. King, Jr. and colleagues discovered shocked quartz in a core drilled near the center of the structure. In 2002, Christian Koeberl with the Institute of Geochemistry University of Vienna published evidence and established the site as an internationally recognized impact crater.
Each year, the city of Wetumpka sponsors annual ‘crater tours’ for the public in cooperation with local landowners and authorities. In March 2007, the Geological Society of America sponsored an international field forum for impact geologists led by David T. King, Jr. and Jens Ormö.
In May of 2007, Auburn University graduate student Reuben Johnson earned his master’s degree studying the impact crater. This work added to a growing body of evidence that Wetumpka’s crystalline “rim” may instead mark the edge of a deep central basin within what was originally a much larger impact crater that has since been almost completely eroded away.
Devil’s Slide is an unusual geological formation located in Weber Canyon, Morgan County, Utah.
The sides of the slide are hard, weather-resistant limestone layers about 40 feet high, 25 feet apart, and several hundred feet in length. In between these two hard layers is a softer limestone that is slightly different in composition from the outer limestone layers. This middle layer is softer, which makes it more susceptible to weathering and erosion, thus forming the chute of the slide. Looking like a large playground slide fit only for the Devil, this site is a tilted remnant of sediments deposited in a sea that occupied Utah’s distant geologic past. Approximately 170 to 180 million years ago, a shallow sea originating from the north spread south and east over areas of what are now Montana, Wyoming, and Utah. This sea extended as far east as the present-day Colorado River and south into northern Arizona. Over millions of years, massive amounts of sediment accumulated and eventually formed layers of limestone and sandstone. In northern Utah, these rocks are known as the Twin Creek Formation and are approximately 2700 feet thick. About 75 million years ago, folding and faulting during a mountain- building episode tilted the Twin Creek rock layers to a near-vertical position. Subsequent erosion has exposed the near-vertical rock layers and created Devils Slide.*
A natural arch is a natural formation (or landform) where a rock arch forms, with a natural passageway through underneath. Most natural arches form as a narrow ridge, walled by cliffs, become narrower from erosion, with a softer rock stratum under the cliff-forming stratum gradually eroding out until the rock shelters thus formed meet underneath the ridge, thus forming the arch. Natural arches commonly form where cliffs are subject to erosion from the sea, rivers or weathering (sub-aerial processes); the processes “find” weaknesses in rocks and work on them, making them bigger until they break through.
Erosion wears away exposed rock layers and enlarges the surface cracks, isolating narrow sandstone walls, or fins.
Alternating frosts and thawing cause crumbling and flaking of the porous sandstone and eventually cut through some of the fins.
The resulting holes become enlarged to arch proportions by rockfalls and weathering. Arches eventually collapse, leaving only buttresses that in time will erode.
This arch, is located near Panaca, Nevada, A drive and a short walk allows you to climb up quickly and see the awesome work of nature.
This arch is made of local Bentonite.
Bentonite is an absorbent aluminium phyllosilicate generally impure clay consisting mostly of montmorillonite. There are a few types of bentonites and their names depend on the dominant elements, such as K, Na, Ca, and Al. As noted in several places in the geologic literature, there are some nomenclatorial problems with the classification of bentonite clays. Bentonite usually forms from weathering of volcanic ash, most often in the presence of water. However, the term bentonite, as well as a similar clay called tonstein, have been used for clay beds of uncertain origin. For industrial purposes, two main classes of bentonite exist: sodium and calcium bentonite. In stratigraphy and tephrochronology, completely devitrified (weathered volcanic glass) ash-fall beds are commonly referred to as K-bentonites when the dominant clay species is illite. Other common clay species, and sometimes dominant, are montmorillinite and kaolinite. Kaolinite dominated clays are commonly referred to as tonsteins and are typically associated with coal.
Sodium bentonite
Sodium bentonite expands when wet, possibly absorbing several times its dry mass in water. It is often used in drilling mud for oil and gas wells and for geotechnical and environmental investigations.
The property of swelling also makes sodium bentonite useful as a sealant, especially for the sealing of subsurface disposal systems for spent nuclear fuel and for quarantining metal pollutants of groundwater. Similar uses include making slurry walls, waterproofing of below-grade walls and forming other impermeable barriers (e.g. to plug old wells or as a liner in the base of landfills to prevent migration of leachate into the soil).
Sodium bentonite can also be “sandwiched” between synthetic materials to create geo-synthetic liners for the aforementioned purposes. This technique allows for more convenient transport and installation and it greatly reduces the volume of sodium bentonite required.
Calcium bentonite
Calcium bentonite may be converted to sodium bentonite and exhibit sodium bentonite’s properties by a process known as “ion exchange”. Commonly this means adding 5-10% of sodium carbonate to wet bentonite, mixing well, and allowing time for the ion exchange to take place. Pascalite is a commercial name for the calcium bentonite clay.
Uses for both types
Much of bentonite’s usefulness in the drilling and geotechnical engineering industry comes from its unique rheological properties. Relatively small quantities of bentonite suspended in water form a viscous, shear thinning material. Most often, bentonite suspensions are also thixotropic, although rare cases of rheopectic behavior have also been reported. At high enough concentrations (~60 grams of bentonite per litre of suspension), bentonite suspensions begin to take on the characteristics of a gel (a fluid with a minimum yield strength required to make it move). For these reasons it is a common component of drilling mud used to curtail drilling fluid invasion by its propensity for aiding in the formation of mud cake.
Bentonite can be used in cement, adhesives, ceramic bodies, cosmetics and cat litter. Fuller’s earth, an ancient dry cleaning substance, is finely ground bentonite, typically used for purifying transformer oil. Bentonite, in small percentages, is used as an ingredient in commercially designed clay bodies and ceramic glazes. Bentonite clay is also used in pyrotechnics to make end plugs and rocket nozzles, and can also be used as a therapeutic face pack for the treatment of acne/oily skin.
The ionic surface of bentonite has a useful property in making a sticky coating on sand grains. When a small proportion of finely ground bentonite clay is added to hard sand and wetted, the clay binds the sand particles into a moldable aggregate known as green sand used for making molds in sand casting. Some river deltas naturally deposit just such a blend of such clay silt and sand, creating a natural source of excellent molding sand that was critical to ancient metalworking technology. Modern chemical processes to modify the ionic surface of bentonite greatly intensify this stickiness, resulting in remarkably dough-like yet strong casting sand mixes that stand up to molten metal temperatures.
The same effluvial deposition of bentonite clay onto beaches accounts for the variety of plasticity of sand from place to place for building sand castles. Beach sand consisting of only silica and shell grains does not mold well compared to grains coated with bentonite clay. This is why some beaches are so much better for building sand castles than others.
The self-stickiness of bentonite allows high-pressure ramming or pressing of the clay in molds to produce hard, refractory shapes, such as model rocket nozzles. Indeed, to test whether a particular brand of cat litter is bentonite, simply ram a sample with a hammer into a sturdy tube with a close-fitting rod; bentonite will form a very hard, consolidated plug that is not easily crumbled.
Bentonite also has the interesting property of adsorbing relatively large amounts of protein molecules from aqueous solutions. It is therefore uniquely useful in the process of winemaking, where it is used to remove excessive amounts of protein from white wines. Were it not for this use of bentonite, many or most white wines would precipitate undesirable flocculent clouds or hazes upon exposure to warmer temperatures, as these proteins denature. It also has the incidental use of inducing more rapid clarification of both red and white wines.
Welcome to Joe’s Valley, a 75-mile long, north-south trending depression graben, what’s a graben you ask?
Horsts and Grabens
A graben is a depressed block of land bordered by parallel faults. Graben is German for ditch.
A graben is the result of a block of land being downthrown producing a valley with a distinct scarp on each side. Grabens often occur side-by-side with horsts. Horst and graben structures are indicative of tensional forces and crustal stretching.
Graben are produced from parallel normal faults, where the hanging wall is downthrown and the footwall is upthrown. The faults typically dip toward the center of the graben from both sides. Horsts are parallel blocks that remain between grabens, the bounding faults of a horst typically dip away from the center line of the horst.
A single graben or multiple grabens can produce a rift valley.
(Horsts are up thrown blocks bounded on either side by parallel normal faults.)
(Grabens are downthrown blocks bounded on either side by parallel normal faults.)
Half-Graben
Half-grabens develop when parallel faults on either side of a block develop, but the block becomes tilted instead of dropping down as in a graben.