The less grand Staircase The uppermost layer in the package of sedimentary rocks representing the Gr

The less grand StaircaseThe uppermost layer in the package of sedimentary rocks representing the Grand Canyon is the Permian aged Kaibab Limestone, just over 250 million years old. That was not the last sedimentary unit deposited in what is today Arizona and Utah. That area continued to see sedimentary rock deposition until the Cretaceous – nearly 200 million years more sedimentary layers on top of the Grand Canyon layers.Those layers aren’t exposed at the Canyon site any more; they’ve eroded away. To the north of the Grand Canyon, the sedimentary package gently folds and is faulted down, exposing layers that are stratigraphically above those at the Canyon. Some of these younger layers are eroded into their own spectacular features – the Navajo Sandstone, for example, makes up much of the exposure in Zion National Park. The Navajo Sandstone is just one of more than a dozen sedimentary units that formed in this area.Just like in the Grand Canyon, these units vary in their properties. Some are well lithified and make steep cliffs like the Navajo Sandstone does, others are weaker and erode back easily. Just as in the Grand Canyon, this setup creates a “Stairstep” pattern, where the landscape steps upwareds at the edge of a resistant layer and then erodes away at a weaker layer.Southern Utah, to the north of the Grand Canyon, therefore, is a gigantic geologic stairstep pattern. This area is nicknamed the “Grand Staircase”. You get that impression in this picture from the central part of the area – stairstepping geologic units.In the 1990s, President Bill Clinton used the power of an early 20th century bill called the Antiquities Act to declare much of the Grand Staircase part of “Grand Staircase-Escalante National Monument”. The original power to declare National Monuments was established in part to allow rapid protection of historical relics without the approval of Congress, which is required to create a full national park, but Presidents have historically used this power to set aside large areas for protection. It is often controversial as setting aside territory for protection means that you can’t make money on the area by tearing it apart, but this power has been used in the past to protect areas including what is today Grand Canyon National Park just to the south - Congress often eventually turns National Monuments into National Park sites once enough visitors begin coming to the area.On Monday, something that has never happened is apparently going to happen. No President has ever shrunk a National Monument – in fact none has ever tried to do so. President Donald Trump is coming to Utah on Monday to declare that he will shrink Grand Staircase-Escalante National Monument and one other, Bears Ears National Monument, created by President Obama just over a year ago.We don’t yet have maps of the areas that will be removed from the national monuments, and some areas have been declared Wilderness areas and have additional protections against development, but there’s a good chance that this photo will not look the same in a few years. The central part of Grand Staircase covers a coal-bearing unit and if the geotag on this photo is correct, this photo sits right above that coal-bearing unit. There are other natural gas deposits in the park as well, and local officials who have submitted maps of new park boundaries typically make sure these areas are outside the National Monument so that they can be mined and drilled.Earlier this year, the US Interior Secretary allowed public comments about what to do with these monuments and the comments were overwhelmingly in favor of keeping them as they were – a required step before making such a change. There are local officials who want to open these areas to drilling and grazing, and the changes will be basically choosing their voices over the voices of the people who submitted comments.It is uncertain what will happen when they try to do this. The text of the Antiquities Act gives the President the ability to declare a monument but there is no law stating how a monument can be undeclared, so there will likely be a long legal case. But…if they do what they want to do, the area in this photo will one day host a coal mine.-JBBImage credit:https://flic.kr/p/KfLBNYReferences:http://wapo.st/2j3q7q5http://zion-gardner-bosch.weebly.com/plate-tectonics.htmlhttp://bit.ly/2io03ck -- source link
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