Stone, Steam and Sand: A Geologic Photo Tour of Southwest Colorado, Part II

i-142e6e6e6ffdd21fa273bd9c17ae5abe-pagosa.jpgHot and Steamy

Ok, I'll admit, the title is a bit gratuitous. But whether you're here seeking hotness, history or geology, you've come to the right place.

The volcanism which formed the San Juan Mountains has settled over the centuries, but, as with the glaciers, signs of a fiery past remain. The layers of hardened tuff have weathered into fertile soils, lending to the thick vegetation covering the area today. Throughout the mountains and in the valley below, some parts of the continental plate are still worn thin. Magma still flows near the surface, heating the groundwater, which bubbles up in hot springs throughout the area.

The town of Pagosa Springs was built on the largest of these springs. The spring has a high mineral content, mainly silica and hydrogen sulfide. The latter is responsible for a distinct odor which permeates the town. (If you've ever been through Glenwood Springs, you might have a hint... Pagosa is about twice as bad. If you haven't, try leaving a dozen eggs in the sun for a week and add them to a steam bath. You'll get the idea.) The silica in the water, which is visible as shining, floating flakes, collects as tufa.

The term "tufa" is fairly ambiguous. The material forming the tufa mounds at Pagosa is not travertine, which is commonly associated with hot spring deposits. Travertine is calcareous sinter, similar to limestone. The tufa at Pagosa, on the other hand, is a siliceous sinter, a type of opal sometimes known as "gyserite". The siliceous tufa mound at Pagosa springs, while now a part of a resort, was large enough to divert the course of the San Juan River. The mounds still grow today, although they're now shaped by pipes and pools.


Long before the resort was built, bathers came to Pagosa Springs. With Puebloan and Chacoan ruins in the area, it is possible that the springs were in use at least 1000 years ago. Even into the historical period, the Navajo and Ute tribes supposedly fought over ownership of the springs. The springs were an important resource; both groups claimed the springs had healing powers. The Ute gave the springs the name we use today. Pagosah meant both "healing" and "boiling waters."

The Old Spanish Trail, blazed by explorers Dominguez and Escalante, went near the springs, but never mentioned them. Then, in 1859, Captain JM McComb led an expedition through the San Juan Mountains, and noticed the springs. A geologist in the party, J.S. Newberry, noted they were "well known, even famous, among the Indian tribes."

"There is scarcely a more beautiful place on the face of the earth." --J.S. Newberry, on Pagosa Springs in 1859.


In 1878, Ft. Lewis was built near the springs, adding to the tension between settlers and the native Utes. A year later, after one of the darkest chapters in Colorado history, the Meeker Massacre, the Utes were designated a small strip of land along the New Mexico border, and were forced to leave the Pagosa Springs area. Around the same time, gold fever came to the Rockies. Since Pagosa Springs spewed silicates, not gold flakes, the site became home to a different community than the nearby mining boom towns (like Silverton.) As the railroad came through, Pagosa Springs became a logging town, with several sawmills, including the Pagosa Lumber Company:


In addition to lumber, Pagosa Springs continued to boast "healing waters." (In fact, the Springs Resort still advertises their supposed curative powers. While I can't claim any proven physical healing, the springs do wonders on the psyche.) In the 1880s, the first bath house was built on the site. In the 50s, motels started appearing, along with the American "road trip." Visitors flocked to the springs, and stayed at the Springs Inn, which later became the Springs Resort. Tourists loved it in the 1890s:



As a tourist passing through a few weeks ago, I must say, the appeal has not worn off in the least. The Springs Resort, while a bit on the pricy side, was well worth the trip. The one large spring has been broken down into a series of pools, varying in temperature from 114 degrees (in "The Lobster Pot") to the icy depths of the San Juan River. A wide fishpond, with a submerged bridge, provides a beautiful centerpiece for the resort. The fish seemed to enjoy sucking algae from the growing tufa, and practically swarmed in certain areas. They avoided the bridge, where kids like my son enjoyed splashing around:


At the beginning of this post, I promised steam and hotness. I'll have to admit... the Lobster Pot was a little too much for me. I stuck my toe in, and that was enough for me. I lasted longer in the cold river. I had to stick with something less "hot and steamy" like the waterfall pool:


I apologize for the lack of "hotness", but you just can't beat standing underneath a waterfall, glimpsing views of the San Juan River and mountains beyond. What can I say? It was a happy moment, and that's what vacation is all about.

I'll finish up this series with a look at the Great Sand Dunes, where we'll continue to look at Colorado geology, as well as a little Coccinellidae porn. (That's the sort of "hotness" you're all waiting to see, I know.)

Historical images via the Western History Photos collection at the Denver Public Library. All other images belong to the author.

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Hello! I happened upon your posting about Pagosa Hot Springs when I was searching for information about mineralization around thermal hot springs. The reason is, I have located some beautiful worn stones that are opalescent in nature and I was wondering what they were called. I believe that your posted information provided the information that I was needing. The stones are ultra white, to white with hints of gold, pink, reddish, purple, bluish, etc. and they can be illuminated with light. That is, light does pass through them somewhat. They have the slightest graininess to them. Also, I do live in CO, I know that I must make it to Pagosa Springs.

By Gary Beane (not verified) on 27 Nov 2007 #permalink

Thanks for dropping in, Gary. I'm not much of an expert when it comes to identifying minerals. I usually look up the geologic map for the area I found the rock in to reduce the possibilities. That usually leads to a good identification, as well as a little information on the way it was formed.

Also, Pagosa Springs makes a fine vacation spot--I hope you make it down there some day! :)