Monday, September 28, 2026

Geology in Pop Culture - Taylor Swift's "Opalite"

Taylor Swift's "Opalite"

Released on October 3rd, of 2025 on The Life of a Showgirl album, "Opalite" is the third track on the album and was later released as a single on January 12th, 2026. 

Discussing the album on The Tonight Show Starring Jimmy Fallon, Taylor Swift breaks down the meaning of the song and where the name came from. In the interview she mentions a few geologically related items:

  • Opalite is man-made opal
  • Similar to how diamonds can also be man-made
  • Gemstones are mentioned in the chorus like "onyx night" 
She also makes note that the purpose of choosing "opalite" is that life is not always going to give you what you want and you are not always going to get your way. Sometimes you have to make your own happiness, like making an opal.

What is an Opal?

Let's break down the geology into bits and pieces. First, what is an opal and how is it formed?

Per the Dictionary of Geological Terms (3rd ed):

Opal: A mineral or mineral gel, SiO2 • n H2O. It has been shown by electron diffraction to consist of packed spheres of silica; water content is usually 3 to 9%. Opal occurs in most colors, is transparent to nearly opaque, and commonly exhibits a marked play of color. It is deposited at low temperatures and is found in a wide variety of rocks and forms. The transparent colored varieties showing opalescence are valued as gemstones. 

 Opalescence: A milky or somewhat pearly appearance or luster of a mineral, such as that shown by opal and moonstone.  

Crystal boulder opal, courtesy of Opal Galaxy

Natural opals are known for that pearly appearance, such as in the sample above, hence the term for the appearance is opalescence. Their formation is also super unique. Instead of forming molecule by molecule, slowing building up as a crystal, opals forms by the amalgamation of little spheres of silica. Because of this type of formation, opal is not actually classified as a mineral, but a mineraloid. Minerals, by definition, must have a definitive crystal structure, which opals do not. 

SEM Photograph of Opal spheres. Image courtesy of Sechrist et al, 2006.

It is because of these tiny spheres, and the way that they are organized, that opals diffract the light the way they do. The size and spacing of the spheres is what determines the color patterns that are seen. 
Diagram showing the formation of Australian opals. Image courtesy of Opal Galaxy. 

Looking at the geological formation of opals, there are two methods that have produced widespread opals in the geological record. Over 95% of opals in the world are found in Australia. These opals began to form around 100 million years ago during the Cretaceous. At that time Australia was covered by a vast sea, the Great Artesian Basin . 

Opal mining locations within the Great Artesian Basin. Image courtesy of Dans Opals.

Over time the sea slowly evaporated and left behind silica deposits. This silica was transported by groundwater into gaps within the underlying sandstone, ironstone, fossils, and ancient wood and precipitated in those spaces. This occurred over very low temperatures and took a long time, resulting in a stable, non-porous structure, of the opals that formed. These opals formed the opal deposits of Lightning Ridge, Coober Pedy, and the Queensland boulder regions. The slow creep of the groundwater is what allowed the orderly, grid-like, construction of the opals, with the tiny sphere forming even sheets. It is these even sheets that produce the opalescence effect that opals are known for.

Ethiopian opal formation. Image courtesy of Opal Galaxy.  

In contrast to the sedimentary, low temperature, method of formation, Ethiopian opal formed from the hydrothermal waters associated with volcanic activity. The hydrothermal waters reacted with the volcanic ash and rhyolites, dissolving the silica, then reprecipitating it within the voids of the surrounding volcanic rocks. They are also hydrophane, meaning they actively absorb water. This means that they are far more unstable than the Australian opals, and much more chemically reactive. They are also much, much younger, having formed likely in the last few thousand years. 

Coming back to Taylor Swift

Let's look at some of the lyrics for "Opalite", specifically the refrain:
And that's when I told you
It's alright
You were dancing through the lightning strikes
Sleepless in the onyx night
But now the sky is opalite
Oh oh oh oh, oh my Lord
Never met no one like you before
You had to make your own sunshine
But now the sky is opalite
Oh oh oh oh oh

She really does only have the two geological terms in the song and they are "opalite" and "onyx". We will start with the big one, opalite.

What is does the word "Opalite" even mean?

The term "opalite" is a very uncommon word. It does not appear in either my geological dictionary, or my Webster dictionary, nor Merriam-Webster's website, nor the Cambridge Dictionary. 

I was able to find some dictionaries, which did have a result including, Dictionary.com which defines "opalite" as: "an artificial gem resembling an opal." This is akin to Taylor Swift's usage of the word. 

However, there is also a second definition for "opalite", which predates the "artificial" usage of the word. Per 1945's Dictionary of Gems and Gemology:

Opalite - "Term used for impure, colored varieties of common opal." 

Geology.com expands upon this and clarifies, stating that the term opalite is used "as a synonym for common opal (natural opal that does not exhibit play-of-color)."


So we have two usages for "opalite".

What does the geological definition of "opalite" mean?

When we look at the formation of an opal, the orderly arrangement of the micro-spheres is essential to the play of color known as opalescence. If that orderly arrangement is not met, then there is just chaos, and the light effects will be absent. Here you will get what is known as "common opal", or "potch", or ... "opalite". 

Common opal, or "opalite". Image courtesy of geology.com. 

In this instance, opalite refers to the non-opalescent varieties of opal. Or in terms of money, the non-gemstone varieties of opal.

What is the synthetic opal definition of "opalite" mean?

Synthetic, or man-made, is exactly as it sounds. These are opals manufactured by man. Unfortunately, these man made opals are more akin to the geological definitions of opalites than they are to opals because, while they may have some opalescence, they lack the opalescence of natural opals. 

Synthetic opals, AKA opalites. Image coutesy of Synthetic Opals.

Because man-made opalites have such a rigid structure, much more so than even highly ordered natural opals, the opalescence that is achieved has a "lizard skin appearance" and lacks the natural variety and irregular patterns. Per Opal Minded: "Most fake opals show fragments of coloured material trapped in a clear base, giving a “shattered” or artificial sparkle rather than the fluid, shifting flashes of a genuine opal."

SEM image of a man-made opal. Image courtesy of Synthetic Opals.  

However, as you can see in the SEM image above, the structure of the synthetic opalite is very much akin to the structure of the natural opals, but it does give a synthetic appearance, which the natural variety feels more variable.

How could "Sleepless in the onyx night" relate to opalite?

I find it funny that she picked onyx, because like opal, it is also composed of silica. Onyx, however, is a mineral, not a mineraloid like opals are. Onyx is a variety of the mineral chalcedony, which in of itself is a variety of quartz. Chalcedony, and therefore onyx, is comprised of microcrystalline quartz instead of one big crystal of quartz like amethyst. 

A black and white variety of onyx. Image courtesy of GeologyScience.

What makes onyx a distinctive variety of chalcedony, is that it has straight, parallel bands of alternating colors, typically black and white. This means that while onyx typically has a "black and white" banded structure, it is distinctly different from natural opalite, both in variety of color and the variety of shapes possible with the color patterns. 

In Summary

Taylor Swift builds Opalite as a means to make ones own happiness from the onyx night. And the fact that you can physically make the synthetic opalite from onyx, plays even more into her song by allowing people to make their own happiness from what they are give. When life hands you lemons and all that. And that's pretty cool.
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Friday, September 18, 2026

Dinos of Disney - Disneyland's Big Thunder Mountain

Disneyland's Big Thunder Mountain

My next entry in the Geology of the Disney parks is Disneyland's Big Thunder Mountain. I am specifying that this is "Disneyland's" version of the ride because even though the ride has been replicated three other times in parks around the world (two of which also have the a centerpiece dinosaur skeleton), this one is unique to Disneyland. 

Here is the setup for the ride from Disneyland:

Legend has it that after gold was discovered in the 1850s, eerie incidents took place in the mine. Trains would take off and race through tunnels… by themselves.

As you enter the cursed cavern, your train speeds up along the rickety track. Shoot under a booming waterfall and dodge a falling boulder from an unexpected landslide as you swoop around sharp turns and drop into desolate canyons.

On this rip-roaring adventure, you may learn that some legends turn out to be true...


For Disneyland's version of Big Thunder Mountain, the theme of the ride is based on Bryce Canyon National Park in Utah. Per The Imagineering Field Guide to the Magic Kingdom, this is distinctly different than the Magic Kingdom's version of the ride, which is modelled after Monument Valley. The reason for this is the aesthetics of the rocks. Monument Valley Tribal Park in Utah and Arizona is comprised mainly of sandstones and shales, making the color palette of Monument Valley to be very red and orange. 

Monument Valley Tribal Park in southern Utah

While the rocks found in Bryce Canyon are a much more pinkish "magenta" color, matching the aesthetics of the nearby Fantasy Land. And since Big Thunder Mountain butts up against Fantasy Land, the mountains were used as a visual backdrop to the land and the color palette was chosen to blend in. 

Bryce Canyon National Park in Utah

The upright spires within Bryce Canyon, called hoodoos, were also mimicked in the upper portions of the ride. You can see them below clearly above the primary dinosaur skeleton. The reason for the color palette of Bryce Canyon is because of the type of rock that it is. Bryce Canyon is predominantly made up of limestone, with sandstone and shale interbedded with it. The rocks were deposited during the Eocene in a large lake bed, forming what is known as the Claron Formation. 


The Claron Formation forms the Pink Cliffs part of Bryce Canyon and is broken up into two individual members: the Pink Limestone Member, which forms the reddish hoodoo rocks of the Pink Cliffs, and the slightly younger White Limestone Member. The White and Pink Limestone Members of the Claron Formation were deposited during the Eocene Period, approximately 60 to 50 million years ago. During that time, this part of Utah was covered by a vast lake, depositing thick layers of calcite that eventually consolidated into limestone. The Claron Formation also includes beds of siltstone and dolostone (like limestone but with dolomite instead of calcite). Limestone is also the same rock that caves form in because they dissolve in slightly acidic water.


While the ride itself was meant to mimic the bedded limestones of Bryce Canyon, it is notable that along the path around the corner to the main entrance to the ride, the rocks there look distinctly sandstone. So much so that the Imagineers carved in cross-beds into the rocks themselves. Cross beds are geological features when dunes are essentially frozen in time and turned into rocks. When sand moves across the desert in a dune they climb up one side of the dune then fall down the steep edge, known as the slipface. This pattern of movement is then preserved in the dune as a cross bed. And depending on how the cross beds are eroded, they can form really cool patterns, such as is imitated in the ride. 


These cross bedded sandstones look amazingly like the sandstone beds of another national park located really close to Bryce Canyon NP, Zion National Park. Specifically the sandstones of the Navajo Formation, which is significantly older than that of Bryce Canyon's Claron Formation. 

Navajo Sandstone crossbeds from Zion National Park

The Navajo Sandstone is Early Jurassic in age, ~180 million years old. It is a very thick, ~1000 feet, eolian (desert) sandstone from an ancient sand sea known as an erg. This part of the ride likely stems from when this entire ride was built for Magic Kingdom, before parts of it were altered to fit in with Disneyland. 


An interesting addition to the ride is the very notable dinosaur skeleton, which is easily visible from the queue. While you are riding the ride you arrive here towards the end, where as you whip around the track, you eventually end up face-to-face with a dinosaur skeleton. At first glance, you would think this is a T. rex skeleton. At least, I believe that is what it is meant to be. 


However, looking closely at the skull, it appears ... off from an actual T. rex. Let's compare it to arguable the most famous T. rex, the Field Museum's SUE. Comparing the Big Thunder Mountain T. rex to SUE (pictured below), the biggest problem with the skull is the teeth. It's as if the designers tried to cram as many teeth as they could into the mouth, and all of the teeth are the same size and more rounded than real -life. Whereas, in the real skull the teeth are constantly coming to replace lost or worn teeth, so the size and spacing of the teeth differ widely within the actual T. rex's mouth. The overall dimensions of the fenestra (skull holes) are also smaller in the Disney skull than in the real animal. The nostril hole (the naris) is noticeably smaller, compared to the real skull, with everything getting a more boxy appearance, however I could attribute that to making the skull more durable with more surface area. 

SUE the T. rex from the Field Museum in Chicago

What I really wondered was where did the idea of this dinosaur come from. Was it meant to be a T. rex or something else. I find it really telling that the D23 post called "The Ultimate Dino-Tour of Disney Parks all Over the World" that goes over many of the dinosaurs in the Disney Parks just calls this "the bones of a dinosaur". No attempt was made at even naming the species, whereas they name the species of many of the other dinosaurs in the post.

Tony Baxter himself, designer of Big Thunder Mountain, stated that the dinosaur bones were meant as a tribute to the previous incarnation of the ride. Parts of the ride and theme were actually taken from the previous renditions of the ride called Rainbow Caverns Mine Train, which was then converted into the Mine Train through Nature's Wonderland. However, I haven't been able to find any pictures of any dinosaurs from those versions. The closest thing I could find, was that the second version mentioned dinosaurs during the ride, but that was about it. 

So although many Disney fans seem to have unanimously determined that this is a T. rex skeleton, Disney itself has shied away from denoting it as anything other than a "dinosaur".   


The location of these dinosaur bones is also suspect. If these bones are located in the "Bryce Canyon" portion of the the design, then they are clearly too old to be there. T. rex lived right up to the end of the Mesozoic, ~66 million years ago. The Claron formation is 60 to 50 million years old, which is too young. However the sandstone related formation on the outskirts of the ride is not the same as seen here with the bones in it. So perhaps this is meant to be a different limestone type deposit that underlies the Claron Formation and is therefore old enough to contain a T. rex?  

References
https://disneyland.disney.go.com/attractions/disneyland/big-thunder-mountain-railroad/
Wright, Alex. The Imagineering Field Guide to the Magic Kingdom at Walt Disney World: An Imagineer's-eye Tour. Disney Editions, 2005.
Sturmer, D.M., Vice, G.S., Sumida, S., and Mary, M., 2024, How geology and paleontology help build the magic of the Disneyland Resort (Anaheim, California, USA), in Van Buer, N.J., and Schwartz, J.J., eds., From Coastal Geomorphology to Magmatism: Guides to GSA Connects 2024 Field Trips in Southern California and Beyond: Geological Society of America Field Guide 70, p. 27–44, https://doi.org/10.1130/2024.0070(02)
https://thedisinsider.com/2019/08/30/disney-parks-weekly-featured-attraction-week-3-big-thunder-mountain/
https://d23.com/the-ultimate-dino-tour-of-disney-parks-all-over-the-world/

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Tuesday, September 15, 2026

Geology in Pop Culture - Snow White and the Seven Dwarfs

 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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Friday, August 28, 2026

Geology of Disney - Disneyland's Matterhorn Bobsleds

 


Disneyland's Matterhorn Bobsleds

My next entry in the Geology of the Disney parks is Disneyland's Matterhorn Bobsleds ride. Based on the real Matterhorn peak in the Swiss Alps on the Italian-Switzerland Border, the ride was initially opened in 1959 and is noteworthy as Disneyland's first rollercoaster.  

Matterhorn Bobsleds looking towards the northeast from the direction of Main Street. 

Per the Disneyland website:
Matterhorn mountain certainly looks like its counterpart in the Swiss Alps— partially thanks to the excellent use of forced perspective. However, the peak is just a bit lower than the original—it’s exactly 100 times shorter than the 14,700-foot-tall real thing.

More than 800 gallons of paint were used to create heavier snowfall on the north-facing—just like the real Matterhorn. Glass beads on the façade glitter like actual snow!

Walt Disney fell in love with the real Matterhorn while filming the 1959 live-action film Third Man on the Mountain.

Back at Disneyland Park, Walt decided to cover a forested 20-foot-high mound named Holiday Hill with artificial snow, add a toboggan run and rename it Snow Hill. However, Walt always dreamed big, and the “hill” soon grew into a 147-foot-tall mountain. The attraction opened on June 14, 1959. 

Image of Matterhorn Mountain facing towards the southwest, looking at the east and north faces of the mountain. Image courtesy of MontBlancLines. 

When it was first constructed, Walt Disney had wanted the Matterhorn to look like it does from Zermatt, Switzerland, while standing on Main Street in the park. This means, however, that the ride is actually rotated compared to its real-life counterpart. When compared to different views of the ride and the mountain, it appears that the ride is rotated between 90 and 180 degrees from real-life. 

Looking towards the west at the eastern side of the ride.

Disney Engineers had then wanted the ride to resemble the actual mountain even more. So, during renovations in 2012, more snow was painted on the northern side of the ride, mimicking real-life. This is because due to the track of the sun across the sky, the northern side of the mountain gets less sun overall, and therefore less snow melts, resulting in greater snow cover. However, since the ride is essentially flip-flopped backwards, that means more snow was added to the wrong side, if you are looking at the real-life counterpart, but the correct side if you assume that the ride is placed correctly. That's confusing, I know. 



But, back to the geology. The real-life rocks that make up the majority of the real-life Matterhorn Mountain were formed 289 million years ago. They are a type of rock known as granodioritic orthogneiss and they belong to a group of rocks known as the Arolla Series. You can think of them as a type of granite. While the peak of the mountain is pre-Carboniferous gneiss, amphibolite, and marble of the Valpelline series, which are all metamorphic rocks. These rocks initially formed underground as magmatic intrusions within the region. 

Geological diagram of the Matterhorn Mountain. Image and following description from the Virtual Explorer. From top to bottom: mainly retrogressed kinzigitic complex of Valpelline series; coarse- to fine-grained and folded gneissic granitoids of Arolla series (GA), from Permian protoliths; Permian gabbro (G) with a thick mylonitic horizon (m) between them and at the base; basal slice of micaschists; calcschists (c), prasinites (p) and mylonitic gabbros (dark green) in the underlying Combin zone (Dal Piaz, 1992; Bucher et al., 2003, 2004).


These rocks were then pulled apart and pushed back together again a few times over the many millions of years, with the final time around 65 to 50 million years ago during the Alpine Orogeny. The Alpine Orogeny occurred when the African continent crashed into the European continent, jumbling rocks from multiple different continents together and forming the Swiss Alps. This layer cake of rocks results with African Crust, Oceanic crust, and European Crust all interbedded, forming the Matterhorn structure as seem in the diagram above. 

"Rocks" on the western side of the Matterhorn Bobsleds. 

Pictured above and below are the "rocks" on the western side of the Matterhorn Bobsleds. While they are clearly painted representations of rocks, they are likely meant to represent the Arolla Series granodioritic orthogneiss. Again, just think of them as "granites". A closer look at these "rocks" are below:


The fracture of the rocks and the speckled pattern of the rockwork, clearly show at least some resemblance to details for the Matterhorn Mountain itself, however it is clear that these "rocks" would never pass the test as something that is actual rock. After the rocks were formed, and then jumbled together, creating the Swiss Alps Mountains as a whole, they were then slowly eroded over time. 

View of the Matterhorn Bobsleds looking roughly towards the south.

This erosion has ramped up over the last 2+ million years, where glaciers had been slowly eroding the mountain peak until only the feature that we know of as the "Matterhorn" remained. This type of geological feature is actually known as a "horn". In geology, a horn is a "high pyramidal peak with steep sides formed by the intersecting walls of three or more cirques, e.g. the Matterhorn" per the Dictionary of Geological Terms. A cirque is a "deep, steep-walled recess or hollow ... situated high on the side of a mountain and produced by the erosive activity of a mountain glacier."

Although I have seen people referring to the Matterhorn as a "karling", which is a geological term I had been unfamiliar with (and one not in my dictionary). Per Huguet (2023), a karling is an "angular peak, with steep walls and sharp ridges, undercut from all sides by glaciers". This seems just a game of semantics to me, but most of the definitions of a horn used the Matterhorn as their "type" specimen, so the Matterhorn has to be a horn, by definition. But that's just my opinion. 


A "cast of a footprint" displayed alongside the Matterhorn Bobsled ride

Alongside the ride there a cast of a footprint which states that it is a "Cast of footprint discovered by Matterhorn expedition south slope, May 27, 1978." This was clearly added after the creation of the ride almost 20 years earlier. While I can't confirm exact placement of this cast of a "trace fossil", it appears to have been added during the 1978 refurbishment of the ride which included the animatronic yeti, Harrold. 

Enlargement of the sign set below the "footprint cast"

While obviously a fake, this does bring in the element of trace fossils into the discussion. Per one of my previous posts "What are ... trace fossils?"

[Trace Fossils} are basically what an animal creates as it does stuff. Stuff can include walking, burrowing, sitting, eating, living, etc. Whenever an animal interacts with the world around it, it leaves evidence, a trace if you will. These traces are what I study. They are not the actual animal but sometimes are found in association with the animal. The easiest way to visualize this that I can think of is with footprints in the snow (as seen below). Footprints are the most basic type of trace fossil. They illustrate locomotion of an organism, whether it is a human, a rabbit, an insect, or anything in between.

And this footprint cast also reminds me of the footprints found alongside Gertie in Animal Kingdom.


So, while it is ancillary to the geological description of the Matterhorn, it does as an interesting wrinkle in the story of the ride.

References
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Thursday, August 13, 2026

Geology in the Wild - Adirondack Mountain Reserve

Back in January of 2022, we were invited for a winter hike within the Adirondack Mountain Reserve, and while we had a fantastic time, there is something more important underfoot that needs to be discussed. And that is the geology! 


Gates to the Adirondack Mountain Reserve. Photo by Gwendolyn Craig from Adirondack Explorer. 

The Adirondack Mountain Reserve (AMR) is a small park located within the larger Adirondack Park near the small town of Keene, NY:

Location map for Adirondack Mountain Reserve (from the NYS DEC)


Per the AMR website:
The mission of the Adirondack Mountain Reserve is to preserve and protect the forests, lakes, mountain streams, and wildlife on our wilderness tract for the enjoyment of our members and, under the terms of a Conservation Easement in perpetuity to the State of New York, members of the public. We will preserve the forever wild character of this forest land and our property at St. Huberts in a manner appropriate to allow the enjoyment of their wilderness beauty. The mission also includes the operation of a club, with associated facilities, for the pleasure and respectful recreation of its shareholders. 

Adirondack Mountain Reserve map. A digital version can be found the New York Almanac 

The park essentially starts in the northeast with the East Branch Ausable River valley. The entrance gate is located along this northeastern border of the Reserve. The park follows the river valley to the southwest through the Lower and Upper Ausable Lakes with another unnamed lake (or at least a lake I can't figure out the name of) situated at the southwestern point of the reserve boundaries. 
Map of the park with some notable points highlighted.

There are several spots within the park where the geology of the region can easily be seen. However, since we were there in winter, even those locations had less than ideal exposures. These spots that we stopped at are highlighted on the map above.

Beaver Meadow Falls

Hiking southwest from the entrance gate one of the first locations that you can see the geology is at Beaver Meadow Falls. Waterfalls are always a great place to check out the geology.

Rainbow Falls

Continuing towards the southwest along the trail, you then come across Rainbow Falls.

Indian Head Vista

And eventually you can make your way up to the Indian Head Vista, with an absolutely gorgeous view of the Lower Ausable Lake. 

View of the rocks on the Indian Head Vista. 

Pictured above are the rocks at the vista itself. However, if we look at the geological map below, it can be noticed that almost all of the rocks within the Adirondack Mountain Reserve are actually the same rock. They are nearly all the orange color, which is denoted as "a" on the Geological Map of New York. 

Geological Map of of the Adirondack Mountain Reserve. The black box indicates the extents of the map pictured above. 


Reading the Legend from the New York State Geological Map itself, I warn you, there is some heavily geological terminology in the paragraph ahead. Per the Legend, the rocks within the park, denoted as "a", are:
Black to light gray or greenish-gray metanorthosite and anorthositic gneiss (Marcy facies); overprint signifies mafic mineral content in excess of 10 percent (mainly gabbroic or noritic metanorthosite and subordinate anorthositic metagabbro or anorthositic metanorite-Whiteface facies). Subordinate members of this series grade through metagabbro or metanorite, to ilmenite-magnetite-rich metagabbro or metanorite, to pyroxenite rich in ilmenite-magnetite, to ilmenite-magnetite ore. Primary subophitic texture is variably destroyed by granulation and recrystallization resulting in a crystalloclastic fabric. Metamorphic minerals include garnet, clinopyroxene, quartz, hornblende, and a plagioclase less calcic than the original. Mafic mineral percentage is contoured in northwestern portion (St. Regis Quadrangle) of the Marcy Massif, contour value being shown on high side of contour line. 
While that is a lot of technical jargon, I will try and break it down. The rock unit that the AMR sits on it known as the Marcy Anorthosite Massif, named after Mount Marcy, the highest point in NYS, which is located just to the west of the AMR. Anorthosite is an igneous rock made up almost entirely of the mineral plagioclase feldspar. And not only does this rock body cover the park, it is massive in size.

Large view of the Adirondack region of New York, showing the full extent of the Marcy Massif. 

Typically when we have mountain, we expect the geology to be jumbled up with many types of rocks overlaying each other. And that is actually what we see for the most part, outside the orange colored Marcy Anorthosite Massif. The Marcy Massif though sits at the center of the mountains, and it is in essence, the core of a dome structure that makes up most of the Adirondack Mountains.

The core of the Adirondack Mountains, the Marcy Massif, is ~1.1 billion years old (Ga), and covers an area of 3000 square kilometers (~1150 square miles). The rock was initially formed as an igneous intrusive magma body that cooled slowly over time, forming the plagioclase rich anorthosite. After formation this rock underwent periods of metamorphism where parts of the rock were altered, mostly along the outer edges. That is a lot of what is in the description of the rock unit above. These metamorphosed regions have various amounts of minerals that are specific to metamorphic rocks.

Cross section of the Marcy Massif across the Adirondacks. Image courtesy of Regan et al., 2019.
The formation of the Adirondack Mountains is where the unique status of the Adirondack Mountains comes into play. While many people may think that the Adirondack Mountains are just a subsection of the longer Appalachian Mountains, they are, in fact, their own distinct set of mountains. The Appalachian Mountains formed when North America slammed into Africa, forming the supercontinent Pangea, and lifting those mountains upwards as a result of the collision around 300 million years ago. Since the breakup of Pangea, these mountains have generally remained inactive and have been slowly eroding away over time. While the core of the Adirondacks formed during the Grenville Orogeny, over 1 billion years ago, the mountains themselves started to be uplifted ~20 million years ago. The reason for this uplift is currently unknown but the result was a dome structure with the Marcy Massif in the center. The way that domes form, it causes the younger rocks to erode away from the central area of the dome due to fracturing experienced during the uplift. This fracturing and erosion is the reason we have some of the oldest rocks in the Adirondacks exposed in such a huge degree. 

The result is that the AMR sits near the center of a massive dome structure, comprised almost entirely of some of the oldest rocks found within the Adirondack Mountains and there are plenty of places within the park to check them out. (Note: there are some slightly older rocks found elsewhere in the Adirondacks, but not nearly as notable as the Marcy Massif.)
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