Friday, September 12, 2025

Geology of the National Parks in Pictures - Grand Teton National Park

My next post about the Geology of the National Parks Through Pictures is from our move across the country from Utah to New York. Along the way we visited 13 National Parks as well as some other sites. This was the first National Park along the way.


You can find more Geology of the National Parks Through Pictures as well as my Geological State Symbols Across America series at my website Dinojim.com.

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Obligatory entrance sign photo. This specific photo however is from our first trip there in 2010.

Geological stratigraphic column of the Teton Range within Grand Teton National Park. Image courtesy of the USGS. 

The rocks that form the Teton Range, the mountains that make up the central focus of Grand Teton NP, date back hundreds of millions to billions of years. The oldest rocks within the part, at the bottom of the stratigraphic column, are 2.7 billion year old (Ga) gneiss. These were formed from the metamorphism of seafloor sediments and volcanic debris caught within a continental collision. 
View of the mountains towards the southern entrance near Jackson Hole, WY.

After the metamorphism of the gneiss, the rocks were infiltrated by magma bodies 2.5 billion years ago. These magma bodies slowly cooled forming the granites that top many of the mountains within the park including Grand Teton, Middle Teton, and Mount Owen. These mountains (pictured below and maybe above if the clouds weren't covering the peaks) form the middle part of Grand Teton National Park. 

Me in front of Grand Teton (the prominent point in the middle), Middle Teton (I believe the sheltered point to the left), and Mount Owen (the short point to the right of Grand Teton) along the Taggart Lake Trail.  

The last of the basement rocks formed 775 million years ago (Ma) when the region started to stretch, resulting in cracks running through the gneiss and granites. Basaltic magma flowed upwards through the cracks and cooled forming dikes of an igneous rock known as diabase. 

Along the shores of Jenny Lake.

After the formation of the igneous and metamorphic bedrocks, sea level rose and allowed for the deposition of a suite of sedimentary rocks starting with beach sands (the Flathead Sandstone at 510 Ma), then deeper water mudstones and limestones. While that was the origin of the rocks within the mountains, we now get to the formation of the mountains themselves. 

This great geological history diagram of the Tetons is located along the shores of Jenny Lake.  

As shown in the geological diagram above, the region that became the Teton Mountains started to expand yet again. This expansion started around 10 million years ago and created the Teton Fault, a normal fault. 

A normal fault

This relatively young age for the mountains makes them far younger than the nearby Rockies, which started to be formed 50 to 80 million years ago. Like the nearby Wasatch Mountains in Utah, the extensional forces that formed the Teton Mountains are related to the extensional pressures from the Basin and Range expansion. 

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

What happens in this type of expansion is that while the blocks of crust are being pulled apart, they start to rotate. This rotation is what produces the mountain peaks. Think of a row of blocks all sitting next to each other, then rotate each of them on their corner so that you have a corner sticking up, that is your mountains. The "V" that is formed between the mountains is your valleys, or basins, which begin to fill up with eroded sediment from the new mountains. These areas become nice flat plains in relation to the nearby jagged peaks. The mountains are still being uplifted through this process. Overall, the blocks have moved almost 30,000 feet along the Teton Fault and continue to move with each earthquake. 

Glacial boulders in Taggart Creek along the Taggart Lake Trail.

While the mountains are built up, erosion wears them down. There is erosion through water activity, like rain and streams, but also glacial activity. While water erosion can carve out phenomenal features over time, it has a tendency to smooth over landscape features. Glaciers on the other hand have a tendency to produce jagged, awe-inspiring landscape features. Many of the striking landscapes were formed during the last few glacial events over the previous 2 million years. Glacial erosion carved out many of the valleys within the Tetons from their "V" shaped stream profile to a "U" shaped valley, and also dug out many of the lakes within the park. Jackson Lake, by far the largest lake in the park, is over 400 feet deep carved out during the Pinedale glacial period 50,000 to 14,000 years ago.

Jackson Lake

After the glaciers eroded the mountains and carried their debris down, the material was deposited along the flanks of the mountains in piles known as moraines. Hiking up the lower slopes of the Tetons brings you through these glacial deposits where you can see many boulders such as seen along the Taggart Lake Trail above. 

Glacial pebbles

Glaciers also tend to mix up sediments from a wide variety of sources, so you end up with the awesome amalgamation of colorful pebbles in the surrounding lakes. While glaciers formed many of the lakes and moraines within the park in the geological past, there actual glaciers still within the park, although much smaller than in the geological past and shrinking ever faster with a warming climate.   
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Friday, September 05, 2025

DINOSAURS!: From Cultural to Pop Culture - 1823: Mary Anning's Plesiosaur

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1823: Mary Anning's Plesiosaur

Letter from Mary Anning to Sir Henry Bunbury illustrating her Plesiosaurus find. December 26th, 1823. Image courtesy of Show.me.uk.

Note: Plesiosaurs are not "dinosaurs", however since their discovery is important to the history of paleontology, they are included within this series.

In December of 1823, Mary Anning, despite having little formal training in the areas of geology, biology, or paleontology, discovered, prepared, illustrated, and described the first nearly complete Plesiosaurus specimen. Mary Anning had long been dismissed by history as an amateur fossil hunter, however within the last few decades she is achieving the accolades for which she rightly deserves. Born in 1799 and growing up fossil hunting along the "Jurassic Coast" (as it is known now), more formally known as Lyme Regis, in the southwest English county of Dorset, Mary had long been known as a superior fossil hunter, despite rarely getting the scientific accolades she deserved at the time. 

In 1811, Mary's older brother Joseph discovered the skull of an unknown animal. Upon continued searching and digging for the animal, Mary managed to unearth the entire 5.2 meter long skeleton of what turned out to be the first complete skeleton of an ichthyosaur. Prior to this discovery only fragments of ichthyosaur skeletons had been discovered and were thought to be some variety of fish vertebrae.

While that was a historical discovery, Mary's most notable discovery was yet to occur. In 1823, Mary Anning discovered a nearly complete specimen of a previously identified animal known as a plesiosaur. Having been previously described by by De la Beche & Conybeare (1821), Plesiosaurus was assumed to have been an aquatic tie between the already known Ichthyosaurus and modern day crocodiles.  However this initial description was based on a flipper and some vertebrae. It wasn't until Mary's 1823  discovery of a nearly complete specimen, which included the very important skull, that a more complete understanding was possible. After discovering the fossil, Anning then prepped, illustrated, and described it in the hopes it would be purchased by someone. She wrote a letter to Sir Henry Bunbury, as pictured above, requesting the purchase of the fossil. 

The letter read:
Sir

I have endeavoured in a rough sketch to give you some idea of what it is like. Sir, you understand me right in thinking that I said it was the supposed Plesiosaurus, but its remarkable long neck and small head shows that it does not in the least (?resemble) their (unclear, possibly another type of dinosaur?) in its analogy to the Ichthyosaurus. It is large and heavy, but one thing I may venture to assure you it is the first and only one discovered in Europe. Colonel Birch offered one hundred guineas for it unseen, but your letter came one days post before. I consider your claim to an answer prior to his. Should you like it
the price I ask for it is one hundred and ten pounds. One hundred guineas was my intended price, but if [I] take the same sum as Col B is offered he would think I had used him ill in not taking his money. - Sir I am gratefully obliged to both you Lady Bunbry for condescending to think of my favourite. He returned to Lyme at midnight quite well. I [am] also greatly obliged for your kind present of the game.

Your most humble servant
Mary Anning

Lyme, December 26 1823

P.S. Sir since I wrote the above I have received an order from the Duke of Buckingham if not sold to send him the specimen on his account. I hope you will not think me impertinent in requesting an answer by return of post I had forgot the Ichthyosaurus it is about four feete long although Not equal to C[aptain] Warrings it is not a bad specimen. The price is five pounds.
Based on the letter, and other similar letters, the fossil was purchased by the Duke of Buckingham. The fossil was then given to the geologist William Buckland, who then let Conybeare formally describe it, essentially omitting the work put in by Anning. The specimen, which is the holotype specimen (i.e., the specimen that the name is based on) of Plesiosaurus dolichodeirus (Conybeare 1824), would eventually be purchased by the British Museum of Natural History (specimen BMNH 22656). Mary Anning's plesiosaur can now be seen at the Natural History Museum, London (new specimen ID: NHMUK PV OR 22656)

Mary Anning's plesiosaur specimen as displayed at the Natural History Museum, London. Image by Adam S. Smith and courtesy of Plesiosauria.com.

A little bit about plesiosaurs. Plesiosaurs were marine reptiles (note: NOT dinosaurs), that existed from the the Late Triassic (~203 million years ago) until the end Cretaceous extinction ~66 million years ago, the same one that wiped out the non-avian dinosaurs. The deposits that Mary discovered this specimen are known as the Blue Lias Formation, and are approximately 200 million years old (the unit spans the Late Triassic Rhaetian Age to the Early Jurassic Sinemurian Age). The rocks are interbedded limestones and shales that were deposited within the deeper offshore shelf waters. The lime mud is thought to have been deposited as a result of episodic storms. 

References
Conybeare, W.D., 1824. XXI.—On the Discovery of an almost perfect Skeleton of the Plesiosaurus. Transactions of the Geological Society of London, 1(2), pp.381-389.

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Thursday, November 30, 2023

Geology in Pop Culture - Snow White and the Seven Dwarfs

 Geology in Pop Culture: Snow White and the Seven Dwarfs

When I started preparing my talk for the 2023 annual Geological Society of America conference (Finding Hidden Geological Lessons in the Media Around Us), I knew that I wanted to talk about Snow White and the Seven Dwarfs. It is a movie that had been on my radar to write about for many years and I figured it would be a fairly easy one to throw into the talk. However, when I started to do my regular research into it, fascinating things started to pop up and I figured as part of my talk, I would give the audience a walk through of my process. And that is what I will do here as well....

When we first are introduced to the eponymous dwarfs of the movie, we discover them as workers in a mine. 

The dwarfs working in Snow White and the Seven Dwarfs

And it turns out they have vocal talent as well, but that's besides the point. To start my research I needed to verify what it was that they were actually digging for. I assumed it was diamonds but I could not recall if it was ever stated as such.  


As the lyrics of their song state: "where a million diamonds shine". So clearly this is a diamond mine, as I was led to believe. 

From here there are several avenues that one can take while looking at this. I first wanted to confirm my suspicions, not just about the diamonds, which we just did, but also about the placement of the story. Another assumption of mine that I wanted to confirm, was whether Snow White was German. The story was written by the German writing pair, the Brothers Grimm, in 1812 as Sneewittchen, indicating that she was likely German. And while this doesn't mean that the Disney version of the character is also German, you can currently meet Snow White in Germany at EPCOT, pretty much confirming that Snow White is German (at least in the eyes of Disney).

Step 1: The original inspiration
But let us bring this back even further. What was the original inspiration for the character. Was she actually German? Did she live in a mining town? And if she did, did they mine diamonds?

The True Story Behind Snow White and the Seven Dwarfs article from Curious Historian. 

It is thought that the real life inspiration to the character of Snow White was Margarete von Waldeck, born to a prominent family in Waldeck, Germany in 1533. Many aspects of her life line up with the fairy tale per the article, but the most important one was that the town of Waldeck was a mining town. The only problem was that the mine was a copper mine, not a diamond mine. And those are two very different things in geology. So although the mine might still have sparkled with the light reflecting off the metal deposits, it is not a diamond mine. 

So we move on. 

Step 2: The Source for Diamonds
Although the real life Snow White didn't live near a diamond mine, we still assume that the character of Snow White is German and lived near a German diamond mine, if such a thing exists. So let us look at real life diamond mine localities. 

There are several ways that diamonds can form, and therefore there are several different types of deposits that they can be found in, but by far the most common types of deposits are known as kimberlites. 

Kimberlite model. Image courtesy of the Kansas Geological Survey. 

Kimberlites are the result of magma from deep in the Earth's mantle that gets erupted on the surface in a rapid and violent type of eruption. Deep in the mantle is where the pressures are high enough for diamonds to form, which typically happens at 150 to 700 km deep in the Earth. The diamonds are then carried upwards in these kimberlite eruptions, where they can then be found on the surface of the Earth.

Global kimberlite localities. From Tappe et al., 2018.

 However, there is a problem when we look at the global distribution of kimberlite deposits.

Blow up of European kimberlite deposits. From Tappe et al., 2018.

There are no kimberlite deposits in mainland Europe. So unless Snow White was Scandinavian or Russian, we are at a dead-end here as well.

Step 3: Alternative Diamond Sources

And this is where the story takes an interesting turn. During my research for diamonds in Germany, I did come across one fascinating story. It turns out that 15 million years ago the town of Nördlingen, Germany was struck by a meteorite. 

Norlingen, Germany. Image courtesy of The Travel.

Known as the Nördlinger Ries impact crater, the asteroid that struck the Earth was going at least 70,000 km/h forming an impact crater 25 km across and 500 m deep. When meteorites strike the surface of the Earth, they do so with tremendous speed, creating very high pressures. The pressures produced from this impact were large enough that they could potentially create diamonds, if the rock they are impacting has the proper carbon concentration (carbon being the element that diamonds are made out of). 

The Nördlinger Ries impact crater. Image courtesy of Digital Geology. 

The rocks in the area of Nördlingen were mostly sedimentary rocks (limestones, shales, and sandstones) however there is also a significant amount of graphite-bearing gneissic rocks. Graphite is another mineral that is entirely made up of carbon and is often the source mineral for artificial diamond creations. The impact of the Nördlinger Ries meteorite was then able to transformed the graphite in these source rocks into tons and tons of microscopic diamonds. 

Article highlighting all of the diamonds from the Nordlingen impact. Image courtesy of The Travel. 

On average the diamonds produced from the impact were less than 0.2 mm, however the total amount of diamonds is estimated to be 72,000 tons! That's a lot of diamonds. So it is my theory that Snow White and the seven dwarfs lived near the Nördlingen impact crater and mined the diamonds from a meteorite impact. 

References
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Wednesday, November 29, 2023

Geology in Pop Culture - The Rescuers Down Under

 Geology in Pop Culture

Released in 1990, The Rescuers Down Under continues the escapades started in 1977's The Rescuers. However, in this adventure our favorite mice, Bernard and Bianca, travel down to the Australian outback (not the steakhouse). Here, they find that the villain of the story, the poacher Percival C. McLeach has kidnapped a boy, Cody, while hiding out in some abandoned opal mines.

 

So what exactly is opal anyway?

Different types of Australian opal varieties. Image courtesy of BlackOpal Direct. 

Opal (SiO2.H2O) is a mineral that forms from the packed spheres of silica (SiO2), also known as the mineral quartz. Opal is a hydrated form of silica where water has been shown to include between 3 and 9% of the total mineral structure. Unlike many minerals, because of how it is formed, opal is amorphous, or without form. This means that there is no crystal structure or cleavage that is seen in most other minerals. Opal forms through the processes of solidification of gelatinous or liquid silica within cracks and voids of other rocks. 

Since the opals are created by spheres of silica and water, the size of the sphere's dictates the colors that are produced. These colors are refracted through the opal like a prism, with larger spheres yielding red or orange, and smaller ones radiating blue. However, this is only the case with precious opals, the more gem quality ones. Most opals, ~95%, are referred to as common opals. These are opals that do not have the "play-of-color" expected in opals as seen in the image above. Although still beautiful, they are harder to identify than the precious opals. 

Location of Australian Opal Mines. Image courtesy of Opals Down Under. 

Despite being found around the world, it turns out that ~95% of the world's supply of precious opals comes from Australia. The opals started to form during the Cretaceous period when there was a large inland sea across Australia. During this time silica rich sands were deposited along the shorelines, then 30 million years ago, during the Tertiary, deep weathering of these sediments within the Australian Artesian Basin released large amounts of soluble silica into the groundwater. This silica traveled into the cracks and fissures in the Cretaceous age rocks where it was stopped by an impermeable layer below. Staying in the cracks and fissures, the opal deposits formed veins, often trapping fossils that also happen to be in the sedimentary rocks such as leaves, dinosaurs, small mammals, and marine reptiles such as Eric the Pliosaur. 

Eric the opalized pliosaur. Image courtesy of Opal Auctions. 

Most of the opal mines in Australia are a type known as open-cut. This means that they basically dig down to the source of the deposit, in this case opal, and clear out anything above it, forming a quarry or pit. This limits the dangers of enclosed mine spaces, allows you to find smaller deposits easier, is much faster with heavy machinery, but is also much, MUCH, more damaging to the environment, destroying literally everything to get to the deposits. 

In The Rescuers Down Under though, they are clearly not in an open-cut mine, they are underground mines. There are some underground opal mines that are found within Australia. One of these locations is the town of Mintabie, found near the north-central portion of the South Australian state. And although they did use open-pit mining in Mintabie, they also had quite a number of underground mines as seen in the picture below.

Mintabie Opal Mines. Image courtesy of Opal Auctions. 

What makes Mintabie interesting is that the mining heyday here was in the 1980's. Even though opals had been know from here since the 1920's, production increased starting in 1976 with the addition of mining equipment able to break through the hard sandstone. During the 1980's, production here was the largest in all of Australia with a peak during 1988. However, after 1988, production quickly declined resulting in lots of abandoned opal mines. 

Warning sign in The Rescuers Down Under

This timing of the opal mines being abandoned during the late 1980's correlates strongly with The Rescuers Down Under, which would have been starting to be in production probably ~1988. Seeing these abandoned opal mines pop up all over the place would have been a good impetus to a setting for their movie. 
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Monday, November 27, 2023

Geology of the National Parks in Pictures - New River Gorge National Park & Preserve

My next post about the Geology of the National Parks Through Pictures is from my undergraduate years when we traveled the national parks during spring break.  

You can find more Geology of the National Parks Through Pictures as well as my Geological State Symbols Across America series at my website Dinojim.com.

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New River Gorge National Park & Preserve

Another park that is within the Appalachian Mountains, the New River Gorge has a similar geological history as other nearby parks like Shenandoah National Park to the east and the Great Smoky Mountains to the south. It also traverses some of the same rock types as the Gauley River National Recreation Area a short distance to the north, however since the New River Gorge is much larger and deeper than the Gauley River valley, the rocks exposed are slightly older (although they also overlap). 


The New River Gorge cuts through Carboniferous Age deposits from the Upper Mississippian age Bluefield Formation (~325 million years old) up through the Middle Pennsylvanian Allegheny Formation (~312 million years old). 

Geology of the New River Gorge National Park & Preserve. Map courtesy of the NPS. 

The different formations are groups of rocks made up of members that were deposited in similar environments. Although the water levels fluctuate up and down during this time interval, overall North America is moving towards Africa in this time period as the Iapetus Ocean was closing up towards the east. Eventually North America will meet up with Africa to form the supercontinent Pangea, but we haven't gotten there yet when these rocks were deposited.

Geological map units for the New River Gorge National Park & Preserve. Courtesy of the NPS. 

The rock units here, as well as at Gauley River NRA, dip towards northwest in a direction that essentially follows the course of the river. One of the oldest formations, the Hinton Formation, was deposited along the coast, with both marine and freshwater deposits represented. It is made up of shales and siltstones, with lesser amounts of sandstones and limestones. It gets up to 1,000 feet thick within the gorge. 


Geologic Profile of the New River Gorge. Image courtesy of WVGES. 


Above the Hinton Formation, the Bluestone Formation is what is known as a regressive sequence, where the sea level slowly went downwards until there is a paleosol (ancient soil) deposited before the Pocahontas Formation starts to be deposited. The paleosol represents an unconformity, which is a buried erosional surface, and signifies the transition from the Mississippian to the Pennsylvanian. Above the Pocahontas Formation is the New River Formation, which is partially seen at the Gauley River NRA. This again represents a coastal environment and the last coastal environment deposited within the region.


The New River itself is often designated the "second oldest river in the world," however this is difficult thing to actually determine. We know that the oldest rocks that the New River erodes through are ~310 million years old, so the river must be younger than that. 




It is also estimated that the river is at least 3 million years old based on glacial evidence that the New River follows the same course as the pre-glacial Teays River a river that used to flow towards the northwest and eventually was the ancestor to the lower reaches of the Illinois River. The Teays River, and eventually the New River, is the only river to cut across the Appalachian Mountains. This is because it predated the mountains and was able to cut down through them as they were lifted up, much like the Colorado River cutting out the Grand Canyon or the Black Canyon of the Gunnison. Estimates for the age of the New River therefore fluctuate between 3 and 310 million years, quite a variance.  


Along the New River Gorge, with the steep sided cliffs due to the abundance of sandstone deposits forming ledges, there are a number of picturesque waterfalls. I believe this is Cathedral Falls, which starts far above me in the picture, tumbling over the New River Formation's Upper Nuttall Sandstone. 

But while there are some of the largest waterfalls in West Virginia within the New River Gorge, there are also smaller waterfalls, that flow down many of the shale deposits along the gorge's depth. 


References
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