Hogbacks
A hogback is a homoclinal ridge, formed from a monocline. Over time erosion takes place and the softer rock erodes from the harder overlying rock. In time this erosion makes a cliff of visible strata which protrudes out on one side, with adjacent sides that have a similar vertical incline. These particular hogbacks are called the Dakota Hogbacks and were formed by the more erosional resistant Lytle and South Platte Formations protecting the softer, slope-forming Morrison Formation. These hogbacks are part of a very large string of hogbacks that run along our front range, they vary in size, dip and exposure depending where you are. A very good example, is where we took these pictures, the hogbacks can be seen from Dinosaur Ridge close to Red Rocks Park.
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| Dakota Hogbacks west of Ken Caryl Valley |
Sandstone Red Rocks
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| We reached the top of this red rock from | |
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| the face shown below on the opposite side of the rock, |
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| the picture does not do justice to how large these rocks actually are. |
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The formation of the sandstone red rocks throughout the eastern front range of the Colorado Rockies can be attributed to events that took place as far back as 600 million years ago. Over about 300 million years, a geological blink of time, the Ancestral Rockies eroded due to a massive intercontinental seaway, paving the way for the creation of the Rocky Mountains formed over the past 70 million years. Earth’s crust or lithosphere is a constantly moving mass that is attempting to balance on the Asthenosphere a molten layer below the lithosphere to create an equal isostatic state or balance of pressure. In this process, the lithosphere’s tectonic plates can interact with other plates and their boundaries.The subduction of the ancient oceanic Farallon plate under the North American plate brought the previously separated Pacific Plate and North American plates together. The isostatic rebound of the North American plate and Colorado Plateau is a result of the Farallon subduction, this event raised the previously eroded and compacted sediments of the Ancient eroded Rockies to expose the strata or layers of rock that form the Ken Caryl Red Rocks.
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Clearly Defined Strata
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| The sandstone rock face that we scaled was actually surprisingly |
| easier to climb than originally perceived because of the rocks grainy texture. |
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| Us at the top (above) and the view from the top (below) |
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An impressive fissure that we found! (crack in the rock)
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Bibliography:
"Geological History." Home. N.p., n.d. Web. 19 Feb. 2013.<http://ken-carylranch.org/community-
news/history-of-ken-caryl-ranch/geological-history/>
"Hogback (geology)." Wikipedia. Wikimedia Foundation, 02 Feb. 2013. Web. 19 Feb. 2013.
Share, Dr. Jack. "The Ancestral Rocky Mountains and Their Eroded Remnants." Web log post.
Written in Stone...seen through My Lens. Blogger, 19 Feb. 2011. Web. 18 Feb. 2013.
