Authored by Not Wanderlust’s head geologist: Evan Dismukes
Why is this called “‘Ask Paula’ like in the newspaper, but for Geology?” Because Cat told me I needed a title and gave me the line “‘Ask Paula’ like in the newspaper.” I thought that was a good way to show my affinity for not taking myself seriously while adding “but for Geology” so you would know what I actually intend to talk about. Now that is out of the way, I intend to write this as an introductory Geology of the National Parks so you can have a little more of a grasp on what you are seeing and touching rather than just “huh, rocks…when’s lunch?”
I am mostly skipping over the Geology from Pittsburgh to Denver because it’s relatively uninteresting to me, but I’ll give you a quick run through. That whole area is mostly sandstones, shales and limestones with the occasional salt formation. These were generally formed when these areas were under water at one time or another throughout history. The salt was left there just like the elementary school experiment where you set a cup of salt water by the window and are left with a crust of salt to make your food taste good. The limestones and shales were formed by dying organisms and do contain valuable amounts of oil and gas. Then there are also the hills around the PA/OH border area that are actually just valleys cut down by streams. However, you also get hills that are debris left over by the large glaciers that covered the northern U.S. during the last Ice Age. Other than that, it’s mostly cornfields. I once heard someone say that “if you scale up a pancake to to the size of Kansas, Kansas would be flatter.” Not sure how accurate that is, but it’s amusing enough to not fact check for myself.
When you think of Colorado, most people think of Mountains, but for people that know, they know that everything East of Denver is actually Western Kansas. So, the first item of geologic or topographic interest that a traveler would come across is Pike’s Peak, which is situated right above the town of Colorado Springs. You may know that town by the cool building that they have there for the Air Force Academy, or not, either way it’s on the East side of the Rockies. Pike’s Peak is one big chunk of granite, just like the rest of the Rockies. What makes Pike’s Peak unique is the distinctly pink color of the granite. It is actually called Pike’s Peak Granite. This pink color is a result of the specific minerals that make up the Feldspar in the Granite. The Potassium Feldspar gives it the pink that it wouldn’t have if it was Plagioclase Feldspar which would be made from Calcium or Sodium. None of this is remotely important to you when you’re driving down the mountain and trying to not melt your brakes or drive off the road.
After being suggested to check out Colorado National Monument when we were probably just going to drive right by it, my attention to the Geology was not what it could have been since I was preoccupied with the hail pelting me in the face. However all was not lost, with some help from the interwebs. Most of the rock you can see is a red sandstone, and the same layer is seen throughout the region and into Utah. What I find most interesting about this layer is that it is made from anchient sand dunes that solidified into rocks. You can still see their structure like in the photo that I told Cat to add to this post. Below the sandstone are layers of Gneiss (and) Schist. One, sorry for the classic Geology pun (Gneiss pronounced nice), two these layers aren’t immediately visible and three while Metamorphoc rocks look super cool they don’t really have any structure so I don’t find them interesting past their looks and puns.
Our next park was Rocky Mountain National Park, of which we saw no Geology for reasons out of our control. The only part that was open was the entry valley. The snow hadn’t been cleared from the rest of the park, and seeing as I only have a 3 season tent and they were supposed to get dumped on with a foot of snow that night, we bounced pretty quickly. Alas! General knowledge and “the cyber” have prevailed. Being part of the Rockies, it’s granite. The more interesting part is how the lakes, valleys and cirques formed. All of these features were carved out by the large glaciers that appeared here during the last Ice Age. While some glaciers still exist, they are a far cry from the size of the ones that shaped this region.
We ended up in Moab. A land which is currently known for being a dirtbag oasis in the land run by the Mormon church, meaning you can’t buy beer with more than 3.2% alcohol so stick with liquor or wine. The town used to be known as a trading post before the railways crossed the nation, and then was reinvented by the Manhattan Project due to its natural resources, most notably Uranium. But now you just go climbing, hiking, mountain biking or drive up mountains in Jeeps.
In Moab, we went to Arches mostly for the rock scrambling, but I’ll say it was the Geology just so I have a reason to continue writing. As you enter Arches, you are greeted by the Moab Fault. The rocks on the east side of the road, at ground level, are the same as the rocks on the west side that are 200+ feet above (remember that red sandstone from Colorado? Yeah, that stuff). The exposed rock is all sandstone created by ancient sand dunes solidifying into rock just like in Colorado; however, the state border enables the rock to erode in new and fancy ways (not accurate) and form the structures that this park is named after: arches. (Insert stereotypical picture of Delicate Arch). Under the sandstone layers is a large salt deposit which controls much of the topography in the area. Salt is less dense than most rock. So, the salt likes to flow upward, like trying to keep a foam noodle at the bottom of the swimming pool, and this creates uplifted sections of rock. Sometimes the uplifted sections fracture and let water seep through and react with the salt. Once the salt dissolves, the overlying rock collapses and formed things like the Salt Valley in the park. But Arches really just gave me a good excuse to make fun of Cat’s cautious climbing style while I waited on top of the rocks that she was trying to scramble up.
Next up in Moab was Canyonlands. Just like Arches has arches, Canyonlands has canyons. The area is cut by the Colorado and Green Rivers. The latter which triggers PTSD from my times mapping the Green River Formation during field camp throughout Utah. Then there is also the mystery spot, aka Upheval Dome. It is what looks like a caldera, but the National Park Service signs indicated that it could have been formed by a meteorite impact or a salt dome collapse like in Arches. Currently, they are leaning toward an impact, but they haven’t determined it for sure. The rest of the park is filled with mesas atop deep canyons all made out of the same red sandstone I can’t stop referencing.