The Mirabilite Spring Mounds At The Great Salt Lake State Park

Last year an amazing rare phenomenon was discovered on the shores of The Great Salt Lake. Mirabilite Spring Mounds. This phenomenon has only been observed in a few places around the world so it was thought to be a unique situation last year. Well, the stars re-aligned and all of the specific conditions occurred again and allowed the formations to start to grow again. I visited twice last winter because I thought it was a once in a lifetime opportunity to see these formations, so I was super excited to hear they were back! I might even visit them again.

Quick Details:

Length: It’s only about .15 of a mile to the mounds. Plus whatever exploring you do.
Trail Type: Out and back.
Difficulty: DR3. It’s beach sand, with a small hill.
Elevation Gain: 17 ft. Ish.
Restroom: Yes, in the visitor center,
Dogs? They are allowed, leashed. But be sure you don’t let them damage the mounds.
Other Info: Highly recommend waterproof boots. The lake was a little lower this year than last, but there was still some wading in 2 inch deep water. However that can fluctuate.

To Get Here:

Head east on i80 to exit 104. Turn right off the exit towards Saltair, and then immediately left (following the signs for the Great Salt Lake State Park and Marina). Follow that to the end. Pay your park fee’s and head in.

Downtown against the snowy mountains (Passenger Seat Photography (PSP)).

Wow. The new airport is kind of pretty, and massive! (PSP)

The Trail:

The Kennecott Smelter Stack. Tallest structure west of the Mississippi.

The small visitor center.

The mounds are located on Silver Sands Beach which is South of the Visitor Center. There is also this short hill down to the beach.

Huh. The unnamed creek is dry right now. Or possibly found a new route. Well, one less random obstacle. Not that is was not much of an obstacle, it was super shallow and easy to cross.

Antelope Island.

The wonky shores of The Great Salt Lake.

We made it. The biggest mound appears to be in the approximate same location. Not as tall as it was last year, but we came quite a bit earlier.

These are just so freaking cool! The minerals form little terraces similar to the Travertine Terraces you see at Mammoth Hot Springs in Yellowstone National Park. With the huge difference of cold being one of the major factors.

The mounds may be smaller, but there are more of the long crystals. Kind of reminds me of hoarfrost.

Westminster College is studying the mounds and has a camera on each one, as well as a pipe.

The eastern mound.

Someone walked a little closer to this than I would have.

Antelope Island again.

The western one. Currently there are only 3 mounds. Last winter there were 4.

Closer.

The smelter stack again.

The Oquirrh Mountains.

The middle mound and the smelter stack.

You can see where some of the formation has dissolved into the water.

Some bigger terraces. I’m not sure what is causing that greenish color, but it is kind of pretty.

It looks like this is where the spring water is coming up.

Top of the mound. The middle mound is definitely the most interesting one.

A quick overview of what is going on here. There is a layer of mirabilite underground here. There are some natural springs coming up and bringing the mirabilite up to the surface. The cold weather is allowing it to crystalize and form these terraces. Once it warms up the mirabilite will break down into a powder called thenardite that is definitely not as interesting. So quick note, even if it were not illegal to take a sample, there isn’t a point to it. It will not hold it’s shape. I go into a little more depth from our first visit.

Closer look at some more crystals.

More formations.

Panoramic.

More terraces.

The green pools again.

The middle mound from the east.

The eastern mound again.

On the first pass, I didn’t realize there was a spring coming up on both sides of the small hill.

Fun terraces. I wonder if the springs coming up is what split the sand there.

Closer look at the crystals.

The other side is a bit more active, and does indeed appear the spring cracked open the sand.

So fascinating. Kind of looks like a geode.

Tiny terraces on the sand mound with larger terraces below.

The front again. I only say ‘front’, as that is the direction approached from, with the ‘back’ being the side closest to the lake.

Closer.

Antelope Island again.

Saltair 3.

The middle mound again.

Long crystals.

With more of the mound.

Close up.

Sparkling in the sun.

More fun terraces.

Another panoramic.

The long crystals.

From the west.

I just love the terraces they make.

The green tinted terraces on the back side.

Where one, or more of the springs come out.

Stansbury Island to the west.

Antelope Island to the east.

Well, I managed to peel myself away from the mounds.

The smelter stack again.

Its crazy, as we were leaving I watched a few people walk right by without even pausing to look at these amazing formations! But, I guess not everyone is a big ol nerd like I am.

The wonky shores of The Great Salt Lake and Saltair.

Heading back towards the visitor center.

Fun lighting on Antelope Island.

The smelter stack above the dry creek bed.

Nobody seemed interested in the mirabilite mounds, and most the other visitors seemed to congregate over here just below the overlook. I thought, maybe just the quickest way to the lake shore?

It wasn’t until we got home that I remembered the other thing I wanted to see here if we ever came back. An old boat wreck had recently been exposed due to weather. DOH! Well, we will probably come see the mounds again, so I will likely have another chance.

The marina.

Antelope Island again.

Silver Sands Beach with the mirabilite mounds and the wonky lake shore.

The smelter stack again.

Saltair 3 again (PSP).

Pretty sunset on the way home (PSP).

Last light on Lone Peak (PSP).

The mounds are still kind of small, and just growing, but I really wanted to see them before the word got out about them again. It was still really fascinating and fun to explore such a unique phenomenon. I was also happy we had them completely to ourselves. I will probably come visit them again before the end of winter. Anyway, super easy, super fascinating, and the word is not yet out. 10 out of 10 squirrels.

As for difficulty, its beach sand with a short hill. There may or may not be some wading, and some sucking mud. DR3.

Dogs are allowed, leashed. However, I would probably leave them home for this unless they are very well behaved. I would hate to be the guy responsible for them getting peed on or what not.