Grumpy G. Gus …. A Sandia Mountain Sentinel

Sandia Mountain granite! Such distinctively gnarly gargoyles, whimisically odd and judgmental, critter and caricature mimics ……. There’s nothing like these boulders! This is a short story about one of a cast of thousands; Grumpy G. Gus.

But there’s a longer story too. Underneath the often comical-looking and recognizable characters that can be envisioned in these boulders, there’s an even more fascinating tale that tells volumes about the geologic history of central New Mexico. Come along and meet Gus and learn a bit about Sandia Mountain granite.

The trails along the lower west flank of Sandia Mountain weave through a fascinating assortment of granite boulders, all jumbled and stacked in huge piles. Frequently hiking these familiar trails can put me into a “zen” state, where my left brain takes over and imagination rules. That’s when all of this gorgeous granite takes on familiar shapes and develops personality.

About a week ago, while topping a rise along the Lower/Upper Trail in the south Copper Trail system, magic happened! The sun cast its morning light across a worn and weathered granite boulder and there he was! Grumpy G. (Granite) Gus. I’m sure Gus (aka GGG) has been there for millions of years, but on this particular day, at this particular time, sunlight emphasized the protruding jaw and shadowy sleepy eyes of this trail sentinel who’s been disturbed way too early in the day.

What a grump!

Did I utter a small noise of surprise, awaking this obviously grumpy lookout? I found myself staring at him in awe. “Apologies to you, GGG, but I’m delighted to make your acquaintance!” “I shall tread lightly and quietly while passing by so you may resume your morning nap, and will endeavor not to wake you on future hikes.” He grumbled a reply (was that my imagination?) and then nodded off by the time I rounded the next bend as the trail passed through Live Oak Tunnel.

GGG resuming his morning nap

Just how old is GGG? I often think about the age of these rocks.

“Today is my birthday… I’m only 1.45 billion years old!”

About 1.45 billion years ago, deep DEEP underground, volcanic eruptions spewed magma that “flowed” and slowly cooled, crystallizing into massive blocks of granite. Then chemical weathering due to groundwater, began eroding these blocks, penetrating the countless joints and fractures in the granite, rounding sharp edges and creating sphere-shaped boulders. Granite sculpting, called Spheroidal Weathering by geologists, continued over millennia underneath what today is known as New Mexico. Here vast land-locked seas rose and drained, tropical environments turned into deserts, all as “New Mexico” migrated on tectonic plates from the equator to its current spot in our world ….. roughly 34degrees N latitude; 105degrees W longitude.

Then 36 million years ago, Earth’s crust began to stretch, thin and rip apart in an east-west direction, basically unzipping the entire state right down the middle, from north to south ….. the Rio Grande Rift began forming. All of those deeply buried and long-hidden massive granite boulders began rising to the surface as the east flank of the Rift pushed and shoved ancient rocks up to nearly a mile above today’s valley floor.

The granite boulders that formed so long ago, about 15,000 feet underground, were now exposed. Rain, wind and gravity helped to exfoliate any residual material clinging to these massive rounded boulders, and eventually revealed their true shapes. Even today weathering is constant as the granite succumbs to the erosive forces of our desert environment.

For now, GGG keeps a lookout for hikers and the occasional coyote between well-deserved naps. After all, it’s “hard” work being a granite sentinel, but someone has to do it!

Full journal page created in the spirit of mirth and merriment!

If you’re a “zen” hiker too, I’d love to know where your imagination takes you!


  1. elainebhills says:

    You continue to knock me out with your geology lessons, making New Mexico constantly more fascinating!

    Liked by 1 person

    1. How excellent! Marvelous comments, Elaine! There’s a never ending visual geology laboratory out our door …. And so much to learn. I figure taking it a little bit at a time makes the elephant easier to swallow! I really appreciate your following and comments on my posts! Hope all is well!


  2. Wonderful geology information! How interesting to see Grumpy Gus in the perfect light! Did you know his location or had been there before? I really love your map, too. I’d like to see the Road Runner rocks, and Road Runners, too! Do you see them much?

    Liked by 1 person

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