Other Geology

Amargosa Mtn

In southern Utah sedimentary rocks are the stars of the geology show–sandstone, especially, and conglomerate and carbonates. Volcanics make some dramatic guest appearances–cinder cones and lava flows. Most of this geology is fairly orderly, horizontal layers of sedimentary rock, canyons carved by water, lava draped over the landscape in a way that makes sense. But not too far away to the west, the geology goes crazy. Great chunks of earth (mountains) are tilted this way and that at thirty and forty degrees. These mountains stand in 20,000 feet of gravel eroded off the mountains as they tipped and raised their edges to the sky. This is the geology of the Basin and Range geologic province. It is the geology of Death Valley and nearly all of Nevada.

Maybe next year, we can explore some of that.


Dinosaur Tracks


(Dinosaur tracks in Navajo Sandstone, Moccasin Mountain Dinosaur Track Site near Coral Pink Sand Dunes State Park)

On Talking Rocks Tours, we spend our days engaged with actual rocks, raw data. In the evenings around the campfire, we spin our theories, ask our questions, ponder the Great Questions. In the day time, on the outcrop, the Bible offers no helpful insights. At night, the rocks are incapable of answering questions of meaning and purpose. They do not explain our wonder and awe. We live in both worlds, together.

Rocks Asking Stories

I wanted to write, “Rocks Telling Stories.” But these rocks ask more than they tell.

The above two pictures belong together, but they were not found together. The photo on the right is a boulder I found in a landslide or gravity slide along Kolob Canyon Road. The boulder is comprised of Shinarump–a conglomerate that is spread butter thin across thousands of square miles. It is recognized by its distinctive pebbles and prevalent petrified wood (top right of the rock I’m standing on). When I first saw this boulder in the landslide rubble, I was puzzled. The Shinarump formation occurs below the Navajo and Navajo debris comprised most of the flow. And when I looked at the canyon walls nearby, all I saw was Navajo Sandstone. So I had to be ABOVE the Shinarump. How could this boulder have landed here? I reconnoitered the area and finally found the bedrock (undisturbed or in situ) deposit pictured on the right. A close look identified petrified wood pieces in this conglomerate, confirming its Shinarump identity. This was up canyon from the slide. The strata in the entire area are dipping south, so as I went up canyon to the north I was actually going lower stratigraphically. Then I realized that the entire area for several miles had been involved in a gigantic slump or mass debris flow. The area of the slide was large enough that a boulder could have been ripped from this location and mixed with the Navajo Sandstone and left where I found it. A tiny mystery solved.

These two pictures are from Kolob Terrace. I was startled to see all these chert pebbles on top of the sandstone that comprises most of Zion Park’s cliffs. Then I was even more startled to see an arrowhead among the pebbles. Note the difference between the weathered surface of the pebble and the freshly-fractured surface of the arrowhead. (Fresh, as in hundreds of years old, maybe thousands. I once found a spear point on a mountain in southern California that was many hundreds of years, if not thousands, old. It looked like it had been chipped out yesterday.) The arrowhead and pebbles raise questions.

Who made the arrowhead? When? Out of what? Did the Indians use a chert pebble?

Then there’s the question: where did the pebbles come from? They form a carpet in some areas on top the Navajo Sandstone. How was the original chert formed? How was that chert eroded or weathered into chunks which could then be transported and rounded. And how did these pebbles end up strewn across hundreds of thousands of square miles?

The next two photos feature my favorite Colorado Plateau mystery.

The photo on the left was taken in the Paria river a short distance above its confluence with Buckskin Gulch. Coming down Buckskin from Wire Grass Flat trailhead, the rock in Buckskin Canyon is one hundred percent sandstone or carbonate or mud. When you reach the junction with the Paria and head upstream, almost immediately, you notice a change in the rock in the riverbed. That is not surprising, the respective streams drain different territory. But what was surprising were the cobbles of banded quartzite. I knew of no source in the area for these rocks. Everything I knew about was either sedimentary–sandstone, shale, conglomerate, limestone–or volcanic. But the quartzite is metamorphic rock. As if finding these rocks in the Paria streambed wasn’t mystery enough, I found a single fragment of the same kind of rock at the top of Hog Canyon Butte north of Kanab. I have found a large pavement of this kind of rock on a prominence out toward Toroweap in Grand Canyon National Park. But there is no known provenance for these rocks. Quartzite (a metamorphic rock) is formed when sand/sandstone is buried kilometers underground (where there is sufficient heat and pressure). If it is going to be eroded, the formation must subsequently be lifted by tectonic activity and raised above sea level so water and gravity can do their work. Where was the original sand before it became stone? How was the original sand buried deep enough to transform into quartzite? If it was lifted, shouldn’t there be some piece of that uplift still standing somewhere? Why is all that is left of this massive activity, just these distinctive cobbles and pebbles?

We’ll ask that question on Talking Rocks 2018. Unless there has been some major scientific breakthrough, we won’t get a decent the answer.

Buckskin Gulch

Some pictures from Buckskin Gulch 2017.


The water was cold. The muck sometimes wanted to keep our shoes. It reached our shorts but not all the way up to our butts.


A curious little sedimentary study: Walls are Navajo Sandstone which have been incised by the intermittent creek/river. In the bottom of the canyon is evidence of continued cutting along with examples of more recent deposition and even more recent cutting. The light colored layers are slack water deposits, placed and cut away in turn. The reddish “powder” is Navajo Sandstone which was eroded back into sand grains up on the high ground outside this canyon. This sand was then rolled, skipped, and lifted by wind and dropped into the canyon when the leap across the top was too far. It filtered down the hundred fifty feet and landed on the “windward” side of the canyon.

What to Bring

Several people have asked me what to bring on the Talking Rocks Tour. I’ll give a list below, but consider it tentative and provisional. These are camping trips. I presume those who come on our tours have some prior experience camping. If you do not, please call me. I want to make sure your first camping experience is pleasant as well as inspirational and informative.

Talking Rocks Camping List

Sleeping bag and pad.

Tent. Some of us sleep under the stars–no tent. If you are not bringing a tent, I need to know so I can have a spare in case of rain.

Food: It is all provided. The menus will be be lacto-ovo vegetarian. Let me know of any special dietary needs.

Dinner ware: provided. However, if you would like to bring your own personal cup and fork and spoon, you can help reduce the waste of disposables.

Coffee and tea: provided.

Lunches and snacks: provided.

Alcohol: none provided.

Water bottles: First one provided. You will need to carry a liter for ordinary hikes.

Sun protection: Bring it. Use it. Hat, long sleeves, long pants, sun screen. If you are inexperienced in desert sun, go overboard with protection. It is easy to uncover. It is hard to reverse sunburn.

Day pack. In addition to a jacket/shell/outer layer, it would be good to include a couple of band-aids, tissue, lip balm,

Hiking footwear: Some wear boots. I wear running shoes. We often hike in sandy washes. Sand is a bigger challenge than angular rocks. You might even want gaiters.

Warm jacket, knit hat, gloves. Nights can be cool. I even take overpants, just to be extra sure.

Trekking poles. Might be useful.

Shorts/swim suit: If we find water, we’ll get into it.

Toiletries/Towel: There will be opportunities to shower every day.

Flipflops or camp shoes.

Headlamp and batteries. Hopefully, this will only be needed in the evening in camp. However, it is required on long hikes, just in case.


If you are driving:

Camp chair. A really valuable item. The tour will provide as many as we can.

A cot. Especially if you enjoy sleeping under the stars.

Talking Rocks 2018

Our first tour, April 22 – 29 is nearly full. Lots of room still available on the second tour, April 29 – May 6.

One small piece of the Grand Staircase, the exposed layers of sedimentary rocks that begin (starting from the oldest) with the Tapeats Sandstone in Grand Canyon and top out in the Claron Formation in Bryce Canyon.