Blog Archives
Sandstone Wind Erosion
Friends, Sandstone comes in many hues from white to a deep gold color in the Wind Canyon area of the southern Little Missouri Badlands. Wind Canyon is a class room for wind erosion effects on soft sandstone. The wind carves caves, caverns and figures in the soft stone. Many have carved their initials in the rock, only to return a short time later to find them washed away with the sand. The bottom image is another wind-eroded area of Wind Canyon showing pencil tips figures. til Tomorrow MJ
Concretions
Friends, these brown round rocks are concretions, a cemented sandstone that is found throughout the badlands. The Romans made a cement from limestone, volcanic ash and clay. These elements were all present in the early badlands and it is feasible that a natural cement was formed from mixtures of limestone (calcium carbonate) ,clays and volcanic ash. This cement concentrated in a softer sediment and the cannonballs were formed. Now the softer clay layer is eroding and these concretions are falling out of the walls.
The most interesting are the cannon balls that are 2-3 feet in diameter that are present in the Northern Little Missouri Badlands. In the southern badlands, smaller cannon balls are often being exposed on slopes of bentonite that has a popcorn texture when dry. The bottom photo shows a cross section of a small cannonball that has a white nodule in the interior. til Tomorrow MJ
Hot Rock
Friends, this holey rock is part burned coal and part scoria. Masses like these are prevalent and scattered throughout an area where a coal vein was burning in the recent past. They resemble lava formed from volcanic activity and are highly vesiculated (new word for the day). Walking the higher ridges around the coal vein area, great areas of the plains have sunk away as a result of the underground clay shrinking in the intense heat. The burned coal is a gray color and sometimes is tightly bound to the adjacent scoria as seen in this image. til Tomorrow MJ
Cap Rock Resistance
Friends, This image shows the principle of differential erosion (i made that up it is not a proper geological term) , the softer material will erode faster (duh) and the red caprock will protect some portions of the clay from erosion. The red cap rock protects the taller pillars, while the foreground pillars are slumping away unprotected, hence differential erosion. til Tomorrow MJ
Rivlets
Friends, I like to call this image “rivlets”, i know it isn’t a proper geological term, but it describes what i see. These little rivlets are not yet rivers, but still display the properties of rivers. The yellow stream on the left shows a braided formation while the middle shows a more meandering stream. Both rivlets are washing yellow sediments downhill following the path of least resistance and going around the harder scoria (red) deposits as they are very resistant to erosion by water. The toadstool formations near the top of the image show the results of erosion on layers of differing densities and hardness. I love the colorful patterns after a rain or in this case, a snowfall, melting and running downhill. til Tomorrow MJ
Bentonite deposit
Friends, don’t adjust your monitor, these clay beds are definitely blue. This bentonite clay, the raw material for scoria formation, is often found adjacent to stripes of lignite coal. Bentonite can be used in pottery to form ceramics and glazes as well as other commercial applications. The most valuable applications are dependent on the ability of very small particles to hold water . Suspensions, colloids and emulsifiers made with bentonite are commercially viable. When water hits these bentonite slopes, the surface is extremely slippery, sticky and mucky. Many times I have come back to camp with clay snowshoes attached to my boots that take days to wear off. til Tomorrow MJ
Erosion at work
Friends, the clay layers are carved by water on this hillside. The inverted v formations result from water flowing downhill. When meeting resistance the flow slows and forms new channels to continue to flow downhill. The badlands are constantly being washed away downstream so get your photos while you can. They say that one inch/ year is being removed by water. til Tomorrow MJ
Scoria Point in the Snow
Friends, this is Scoria Point on a September morning when we had an overnight dusting of snow. The next day it all melted, but the day was perfect for photography. The saturated reds of the rock, golds of fall grasses, and greens of cedar trees as well as the fall foliage made for a delightful day. I have visited these hills at least once a year since I was nine years old, and the landscapes never cease to amaze me. My love for this country is very deep within me, I hope i can share it adequately. til Tomorrow MJ
Mountain of Red Rock-Scoria Point
Friends, this is a formation called Scoria Point located within the Theodore Roosevelt National Park in western North Dakota. This red rock or scoria appears many shades of red, from pink to purple and all the oranges in between and the shade is dependent on the light. The day this image was taken, the light was slightly diffused through some clouds and the color appears a rusty orange with pink accents. But in the evening with a setting sun, the hill appears a bright orange and in the snow with cloud cover, the rock appears a very deep almost iridescent red. I haven’t yet captured the spirit of this rocky scene, but i keep trying. til Tomorrow MJ
Badlands Red Rock
Friends, this red rock is fragile and will break like any good china cup. The formation process is similar to producing bricks or fine tiles. A clay (bentonite) is baked by a coal vein that is burning underground. The coal is a soft lignite and may be spontaneously ignited or the vein may be lit by grass fires whipped by the wind. These fires may burn trees and then travel down the roots to the seam underground. When the various clays are baked and glazed by the igneous process, they are a form of porcelain or as it is locally called, scoria. When a chunk of this light rock is dropped, it clinks on a hard surface, and it is often called North Dakota Clinker. I know i am at home when i see the scoria peaks at sunset. til Tomorrow MJ
