Geology of the Salt Lake Valley

One of the things I wanted to do before I moved from Utah was to get a nice panoramic picture of the Salt Lake Valley from above Salt Lake City. Here is a shot of the Salt Lake Valley looking south (so east is left and west is right). In the picture the Wasatch Mountains are on the left side of the valley and the Oquirrh Mountains are on the right side of the photo.  

The reason for this, besides just being a beautiful valley, was the geological setting of the valley. The Salt Lake Valley holds an important place, geologically speaking, in the landscape of the United States. The valley is the eastern most extension of the region known as the Basin and Range. 

Coverage of the Great Basin. Image courtesy of the NPS.

The Basin and Range extends from the Wasatch Mountains in the east to the Sierra Nevada Mountains in the west. It encompasses the western half of Utah and pretty much all of Nevada, as well as parts of Idaho, Oregon, California, and Arizona.

Illustration of the plate tectonics of the west coast of North America with the Farallon Plate subducting beneath North America. Image courtesy of the NPS. 

The formation of the Basin and Range Province began long ago when a plate known as the Farallon Plate was being subducted under the west coast of North America. This occurred along the Californian coast and south into Mexico. 

Evolution of the western coast of North America going from a subduction zone to a transform plate boundary causing the formation of the extensional Basin & Range Province. Images courtesy of the NPS.

The subduction, where one plate goes beneath another, produced volcanoes in California and other places in the American west, and it also squeezed North America. Around 40 million years ago, most of the Farallon Plate was completely subducted beneath North America. What that did was a few things:

1. It released the pressure that was squeezing North America, like someone releasing a squeezed sponge. 
2. The subduction zone was no longer. In it's place a new plate boundary formed, a transform plate boundary known as the San Andreas Fault.  

As the pressure was released, the plate started to expand. This expansion produced a series of north-south running blocks, which were rotated from the pressure release. These rotated block produced the north-south running mountains we see across the region today, as well as the north-south trending faults that border all of the mountain ranges.  

As the mountain ranges were rotated upwards, they were eroded. The eroded material washed down into the gaps between the mountains, producing the sediment laden valleys we know so well today, including the Salt Lake Valley. This is the reason that earthquakes can also be particularly dangerous in this region, because all of the sediment has a tendency to shake like Jell-O in an earthquake. 

The eastern valley produced from these rotational blocks was the Salt Lake Valley, with the Wasatch Fault, the fault at the base of the Wasatch Mountains, representing the eastern most extension of the region. It is also one of the most active faults of the whole region since it is a boundary fault. 

This can also be seen in the façade I designed for the University of Utah parking garage seen here with some of the various Basin and Range mountain ranges as well as their fault lines. 

Geological Christmas Gift - Coal Bags

 Last year I thought it would be fun to put together some coal bags for those of us who really enjoy getting coal for Christmas (or any of the season's holidays). I have the bag available up on Etsy right now for anyone interested.

While living in Utah, we lived close enough to a prolific coal seam that jutted out along a road cut on a highway, so I collected a few samples to be used in the gift bags. 

Coal along the Helper, UT roadcut. The coal belongs to a geological formation known as the Blackhawk Formation. 

Stratigraphic column of the Blackhawk Formation and neighboring formations from the Geological Survey publication on the rock units.

The Blackhawk Formation, specifically the coal bearing member, is Late Cretaceous in age. Specifically it is from the Campanian, ~80 million years ago. Coal forms in swamps. Living plant matter dies over time in the swamp, but there is so much decaying plant matter in a swamp that there's not enough oxygen in the water to break it all down. So the plant material builds up over time, and eventually gets buried by mud, sand, silt, or other sediment. This preserves the plant matter that slowly gets buried and cooked over time. The cooking process removes all of the other materials in the plants than the carbon, which is what the coal is.

For the gift bags, I wanted to include as much of that information as possible. 

Text on the inside of the tag:

Type of rock: Bituminous Coal

Rock Source: Blackhawk Formation (coal bearing member)

Age: Late Cretaceous (Campanian, ~80 million years old)

Environment: The coal you hold was once plant matter in a swamp. There was so much life in the swamp, that when the plants died there wasn’t enough oxygen in the water to break them down, so the plant matter built up. Eventually this plant matter was buried by sand and mud, and over time the plant matter was slowly “cooked” below the surface of the earth until all that was left was the carbon from the plants, creating coal.

I also wanted to include two varieties of gift tags that you can choose from.  

The traditional "Naughty" version, where the person getting the coal was bad:

Someone was naughty,

And made Santa mad.

So, this coal is your gift,

Cause let’s face it; you were bad!

Or the geology version, where the person getting it just likes rocks. 

Not everyone who’s been bad gets coal.

Sometimes that may be one’s very goal.

So here is a gift to stuff your sock.

As someone who really love rocks.

Each gift bag available here comes with:

- 2 to 4 pieces of coal that total about 6 ounces in weight.

- A red felt gift bag with draw string

- A naughty or nice tag, complete with geological information about the coal on the inside.

So if you are interested, or know someone who is interested, please pass the word along :-). 

What are ... Archaeologists vs Paleontologists vs Anthropologists

 For the next entry into my What are ...? series, I am looking at something that is often confused, the difference between an Archaeologist and a Paleontologist. This confusing was brought up recently when I was reading the question cards in my daughter's game of Dino Math Tracks:

Within the game, there are cards where the person must solve the math word problem in order to figure out how many spaces they can move. This is the card in question:

Archeologists must ship 24 tons of dinosaur bones to the museum. If each truck can hold 2 tons, how many trucks do they need to ship the bones? Move forward that number of spaces.

This brings up a common mistake in everyday life: mistaking what an archaeologist is versus a paleontologist. 

Archaeologist: According to Webster's Dictionary archaeology is the study of past cultures through their surviving relics. 

This means that an archaeologist studies the remains of civilizations that people leave behind. This can include some things like arrowheads to the pyramids, bowls to clothing, eating utensils to cave dwellings, and everything in between. Archaeologists study the changing human behavior but not the changes in our physical selves. This article puts it perfectly:

... archaeology is the reconstruction of ancient behavior from the things people left behind.

Paleontologists: Paleontology on the other hand is the study of life in past geologic periods, according to Webster's Dictionary.  

This means that paleontologists are focused on the life that once lived and often how it connects to the life that is still around. They can look at the physical remains of the animals and plants to reconstruct what they looked like and how they moved and interacted. They can also look at the behavioral remains left behind like footprints and bite traces to determine how the animals lived. All of this combined will often give paleontologists a fairly good idea of what past environments even looked like. Paleontologists are most often thought of as studying dinosaur bones, but there are many types of life that a paleontologist can study and if there was once something living on this planet that we know about, you can be sure that there was, or is, someone that has studied it. 

The difference here is that paleontologists can study any animal remains, but they don't study the behavioral creations of humans. The question then arises, that is humans are animals, then wouldn't a paleontologist then technically also study humans. Here is where lines start to get blurry and people's definitions may vary but there is a cross specialty that encompasses both worlds, and that is anthropology.

Anthropologists: Anthropology is like the blurry boundary between paleontology and archaeology. Webster's describes anthropology as the science of the origin, early development, and culture of humankind. 

Anthropologists study the human remains to discover how our species has evolved over time, physically, behaviorally, and culturally. Archaeology, on the other hand, is typically seen as a sub-category of anthropology focusing only on the physical items humans created and left behind, while human paleontology (a.k.a. paleoanthropology) could be seen as another name for the study of the human evolution and remains typically seen as one of the sub-disciplines within the overarching body of  anthropology. 

As this website puts it: The goal of anthropology is to better understand the different cultures of human history and to look for solutions in human problems. Anthropologists use social, biological, and physical science to get a better grasp on human cultures.

Geological Destination - Escalante Petrified Forest State Park

 Just outside of the town of Escalante in Utah is the Escalante State Park, also known as the Escalante Petrified Forest State Park. The park sits on the shores of the Wide Hollow Reservoir, which is a great little reservoir to swim in or boat and fish. But the geological destination for this park is the Nature Trail, also known as the Petrified Forest Trail. Along the trail, large petrified trees are easily visible. Although not as densely packed with trees as Petrified Forest National Park, this is still a fantastic view of the logs in an unexpected location. 

Many of the logs are easily visible from the trail. The park itself preserves about 5.5 million tons of petrified wood across the 1,400 acres. These logs had been petrified, which is a type of fossilization specifically referring to trees. The wood molecules had been slowly replaced over time by molecules of minerals, in this case silica, also known as quartz. Over time all of the wood molecules would have been replaced with the silica creating a tree shaped rock that preserves many of the intricate details from the tree itself. These details include the tree rings and bark. 

The state park sits right in the middle of several National Parks including Grand Staircase-Escalante National Monument to the south and Capitol Reef National Park to the north. 

The logs sit within the Brushy Basin Member of the Morrison Formation from the Late Jurassic (~130-140 million years old).  The wood is thought to have eroded out of the overlying conglomeratic part of the Brushy Basin and tumbled down the slope to the lower mudstone, where it sits now. The mudstone then erodes much more easily than the harder, and heavier, quartz logs, so the logs remain behind as the other material is washed away/eroded over time.

The petrified wood layer within the Brushy Basin Member is one of the youngest layers of the Morrison Formation. This stratigraphic section is from the Utah Geological Association Publication of the Escalante State Park Geologic Trail Guide. 

During the hike you get a pretty good overview of the campground and the reservoir as well as the various layers of the Brushy Basin from the caprock of the area, the conglomeratic unit, to the underlying softer mudstone. 

The trees were deposited within a braided stream system, much like the above braided stream system from Banff National Park in Canada. These streams are often slow moving stream systems with periodic large amounts of water, so they are able to move a large array of sediment sizes from sand to gravels, and even large pebbles and boulders. These sediments are often more varied and larger than are frequently found in more meandering streams like the Mississippi River. The trees in this park would have likely grown up on the banks of the river, when they were uprooted and rolled along the river until they came to rest in the gravel and sand channel.

View of one of the logs highlighting the rings. The trees in the park are not of the best preservation to be able to identify them very well. However, some of the trees had been identified as conifers, however the level of preservation is not fine enough to be able to identify which species of conifer.

Dinos in Pop Culture - LEGO Dinosaurs

 When LEGO decided to release the Dinosaur Fossils set it became a "must have" for me. These are far from the only dinosaurs LEGO has ever produced as well but besides being specifically the skeletons of the dinosaurs (and Pteranodon, which is not a dinosaur) they are set up as if they were museum displays. This makes the paleontologist heart in me happy. 

The line of LEGOs comes from their LEGO Ideas sets, which are LEGO sets that had been submitted by  users as potential builds. These ideas/suggestions are then reworked by LEGO professional builders to make them work in a mass market possibilities. This set was originally designed by Jonathan Brunn, who is a French graphic designer and reworked by the LEGO Designer Niels Milan Pedersen. 

The set itself comes with the three main fossil skeletons, Tyrannosaurus rex, Triceratops horridus, and Pteranodon longiceps. On top of that it comes with a little paleontologist, box of paleontological tools and books, as well as a "LEGO sapiens" model (i.e. the bones of a LEGO figure).  

The models are set up as skeletons in a 1:32 scale with the skeletons on a display pad complete with identification plaque. Most of each figure is adjustable as well, so that you can get the models in the pose that you really want. 

Even though they are obviously LEGO figures, the models themselves are actually quite awesome. They are not a 1-to-1 recreation of a real life skeleton, but they are as close to what would happen if a real life skeleton got put through a LEGOification machine. 

And I love the variety that you get. You have the two stalwarts of dinosaur popularity representing the carnivores (T. rex) and herbivores (Triceratops), and you also have the non-dinosaurian flying Pteranodon complete with a stand so you can place it in "flying mode". 

Your crate of goodies also comes with some bones, a magnifying glass, an egg, a cup, a rock hammer, a book about fossils, and some unidentifiable tools.  

Overall, this set earns an A+ from me.

Utah's Pandemic Earthquake of March 2020

Continuing on through my pile of photos I come across the start of the lockdown in March of 2020 and I am reminded that at the very start of the lockdown, Utah was hit with the largest earthquake it has seen in recent memory and the largest earthquake I personally have ever been a part of. 

On the morning of March 18th, 2020 at 7:09 am local (MST) time, western Salt Lake County was hit with a 5.7 magnitude earthquake. At the time we lived in the valley to the west, not 13 miles from the epicenter of the earthquake. The epicenter is the spot on the surface directly above where the fault moved (known as the focus). Earthquakes occur due to energy that is released after a slip occurs along a fault. This energy produces shaking in the ground, both up and down, side to side, and back and forth. This motion of the ground is what we feel on the surface. 

Upon the start of the earthquake we were getting ready for our day. The wife was getting ready for work, the child, having off of school that week for spring break, was playing in her room, and I was still in bed. Upon the start of shaking I jumped out of bed and grabbed her from her room into the doorframe of my bedroom since our bedrooms were directly across the hall from each other. 

The doorframe is one of the safest locations in a home during an earthquake because structurally it is one of the strongest spots. Lights, parts of ceiling, pictures, and stuff on shelves are less likely to fall on you in a door frame. Walls are also less likely to collapse there. Under a desk or table is also another safe location for the same reason, the structure will provide protection from falling objects. Running outside is actually a terrible idea because the initial shaking of an earthquake only lasts a couple of minutes at most, and in that time you won't get very far and around the outside of a building is the most dangerous place to be since things like bricks can fall off a building and glass can break from windows. So, stay put in a safe location, if possible.   

Above is the initial shake map from the earthquake from the USGS. Earthquake.usgs.gov is my favorite website for quickly identifying earthquakes and their sizes and locations. The website is updated within about 5 minutes of an earthquake. This is also helpful during the numerous aftershocks we felt to wonder if they were an actual aftershock or just a passing truck. The shake map tells you the location and the size of the earthquake, as well as how far away it was likely felt. This information will get refined over the coming hours and days as more information is obtained.

One of the things about an earthquake that I never realized is that I was constantly feeling aftershocks for months afterwards, regardless if we actually had them or not. Having never been in an earthquake, I thought it would be super cool as a geologist to be part of one. I was wrong. It was terrifying. And still is, because there is no warning and no way to really get mentally prepared except to have everything you need in the event that one happens and your home or place of work to be structurally prepared. 

Within a few hours the area was inundated with aftershocks including four of a magnitude 4.0 or greater. The above map represents the shake map of the 4.6 aftershock that hit in the afternoon of March 18th. 

Above is the most up to date shake map of the main, 5.7 Magnitude earthquake. This is what is called a Modified Mercalli Map, which uses people's real life experiences to help shape the impact of the event. If something fell of a shelf in your house you would have felt a different different level of intensity than if your entire house fell down. Each of those dots represent points of data where someone contributed to the map. If you are a part of an earthquake, this is a great way for everyday citizens to participate in citizen science at USGS's Did You Feel It. 

As identified by the University of Utah Seismographic Station, there were over 2,500 earthquakes that took place in the same area from March 18th through the following year. 

UUSS's seismic graph from earthquakes.utah.gov.

Of all those 2,500+ earthquakes, all but one was identified as an aftershock, the one being the main event earthquake. An aftershock is an earthquake along the same fault line that occurs after the main earthquake and is always lower in intensity. If for some reason we had an earthquake that was a 6.0 after the 5.7, the 6.0 would not be considered an aftershock. At that point the 5.7 would be renamed a foreshock (taking place before the main earthquake) and the 6.0 would become the main earthquake. So in actuality, aftershocks are only identifiable as such as long as they are smaller than the main earthquake and to understand the entire picture of an earthquake, some time has to progress until we see all of the impacted fault movement and earthquakes.  

The Basin and Range Province. Image courtesy of Miracosta.edu.

Geologically speaking, Utah is located along the eastern edge of what is called the Basin and Range Province. This is an area that is actively undergoing extension. Meaning the the plate is essentially being stretched apart here. The result of which is what we see, a series of parallel, north-south running mountain ranges with valleys in between. Intermixed with all of this is a series of volcanic eruptions occurring all over the region due to the thinning crust. I had covered a bunch of Utah's volcanic legacy in a previous post HERE.

Extensional activity in the Basin and Range Province. Image courtesy of Miracosta.edu.

The types of faults most commonly associated with this type of extensional activity is known as a Normal Fault. 

A Normal Fault is where the overriding block (the hanging wall or head wall) moves downward in relation to the under-riding block (the footwall). 

Location of the Wasatch Fault in Salt Lake City.

Along the eastern edge of the Salt Lake Valley is the Wasatch Fault, the largest fault in the region, and also a Normal Fault. Generally it is considered a "fault zone" because of all of the offshoots and short segments of the fault, especially since scientists are not 100% sure about where exactly the fault is located in all locations. 

Wasatch Fault Scarp in Salt Lake City

Where the fault does hit the surface in a fairly well identified area is in the eastern edge of Salt Lake City, where a fault scarp can plainly be seen. A fault scarp is the cliff or surface disruption along the surface rupture of the fault where the two blocks can easily be identified, as in the picture above, because the one block juts up compared to the other block. But a fault isn't likely to cause an earthquake just where it surfaces. The fault also extends many miles below ground. And as can be seen in the diagram above and below, the Wasatch Fault curves towards the west, below the Salt Lake Valley.

A great graphical representation of the Wasatch Fault below ground from earthquakes.utah.gov.

And that is where the earthquake of March 18th occurred on. The movement occurred on the Wasatch Fault, but it occurred 6 miles (10 km)  below the surface. This is the reason why although the fault lies along the eastern part of the Salt Lake Valley on the surface, the earthquake occurred almost on the western edge of the valley on the same fault. 

Right now it is estimated that an earthquake of a 7.0 to a 7.6 will occur sometime in the future along the Wasatch Fault Zone. This is based on historical estimates of the previous earthquakes along the fault and size estimates based on the size of the fault. Earthquakes are only able to generate energy based on the size of the fault. The larger the fault, the larger the potential earthquake. So, based on the size of the Wasatch Fault, a 7.6 would be the maximum size that an earthquake could be. However, that would be detrimental to the region because many buildings and other infrastructure are not built to withstand an earthquake of that magnitude.

The odds of a 7.0 earthquake occurring within our lifetimes is generally on the low side, though. So, although there is no reason to constantly live in fear, there is reason to build our community with earthquake resiliency in mind. Especially since our buildings will hopefully far outlast us. 

Random Dino Pic - Dino Shrub

 Cleaning up my phone's pictures and I came across this one from back in March of 2020 before lockdown went into effect from a trip we took down to Moab, UT for a Half Marathon that ended up never taking place.

It's a lovely T. rex shrub :-). 

Dinos in Pop Culture - Magic Kingdom's Maleficent Dragon

 

For my final Dinos of Disney post (for now), we look at what is not a direct dinosaur, but possibly the evolution of dinosaurs' influence on medieval cultures over time, and that is the dragon! 

I had talked about it before but there is evidence that dinosaur bones possibly led people to create dragons over time. And as time continued these dragons have evolved within our culture just as animals evolve in nature until we are left with the remnants of that evolution. So, for that reason, I like to treat dragons as if they are the descendants of dinosaurs. And with that I present the dragon of Magic Kingdom: Maleficent.

Premiering in 1959's Sleeping Beauty, Maleficent was the primary villain of the movie appearing in human form for most of the movie until the climax at the end where she transmogrifies into the dragon. This particular dragon was part of one of the many parades that had gone by when we were there in January of 2020. 

The parade float is from the Festival of Fantasy parade and the dragon itself was actually mobile and spit fire out of its mouth. 

Maleficent in her dragon form from the original Sleeping Beauty.

You can find all of my Dinos of Disney compiled on my website at Dinojim.com.

Paleo in Pop Culture - Hollywood Studios' Galaxy's Edge

 

Although not dinosaur related, there is another strong paleontological connection in Hollywood Studios and that involves the entire backdrop of the Star Wars Galaxy's Edge land within the park. 

The entire park of Galaxy's Edge takes place within the canon of Star Wars on a planet named Batuu. This settlement on Batuu is known as Black Spire Outpost, named after the spires located throughout the backdrop and within the park itself, specifically one spire in particular that is blacker than the other spires. Here is the blurb from starwars.com:

"Widely known for the petrified remains of its once towering ancient trees, the spires now stand guard across the river valleys and plains and have long captured the imagination of travelers to this planet."

In canon, these spires are petrified trees that were petrified in place, where the tops of the trees were not preserved (either they eroded away over time or only the bottoms were petrified and the tops decayed before preservation). Petrification is a specific type of fossilization that refers to trees. This process involves the replacement of each living/biological molecule with mineral molecules. 

The replacement process, or permineralization, occurs when minerals dissolved in water, frequently silica in the instance of petrification, flow through the water and do a (typically) 1-to-1 replacement of the molecules leaving behind a nearly perfect replica of the tree. These petrified trees no longer contain living (or dead) tissue but are essentially tree shaped rocks. For this process to occur though, the trees need to be buried, or at least submerged, in silica rich waters. It is also helpful if there is a lack of oxygen, because without oxygen the trees can't decay. For this to have occurred with all of these trees still standing upright, the entire region would need to have been buried or flooded with anoxic (lack of oxygen) waters or sediment (mud). 

The inspiration for these petrified trees came from a National Park within northeast Arizona, Petrified Forest National Park, where one can actually go see real life petrified trees. The difference here is that although the trees in Petrified Forest are huge, they are nowhere near as big as the ones in Black Spire Outpost, and also most, if not all, of the trees in Petrified Forest are preserved after they had fallen over.

Here are some of the lovely petrified trees from Petrified Forest National Park. I had done a post about the geology of Petrified Forest a little while ago and contains some more pictures and information after the fossilization process.

A close up of an actual petrified log from Petrified Forest National Park.

Back to Black Spire Outpost.

Here is a close up shot of one of the petrified stumps that really looks a lot like a petrified log. The artisans at the park spent a lot of time crafting each spire individually so that they not only looked like trees, but petrified trees, and each unique so they don't look cookie cutter. 

Here are some more spires off in the distance. These petrified tree spires also share a relative in Disney's California Adventure with the petrified Millennium Tree on the Redwood Creek Challenge Trail.

You can find all of my Dinos of Disney compiled on my website at Dinojim.com.