Ranger: Hello, I’m Park Ranger Suzanne and this is a Chiricahua National Monument Geology Ranger Minute. Today we’re at Massai Point, the end of the 8-mile scenic drive, 6,870 ft above sea level. People come from not only Arizona and the United States, but from all across the world to enjoy this ‘Wonderland of Rocks’. Whether it’s from the scenic overviews, or along the 17-miles of day use hiking trails. As you explore, look for the faces, the shapes, give them their own names, and let your imagination soar. However, the peace and quiet we enjoy today had its start in a violent volcanic eruption an estimated 27 million years ago. Let’s find out where that volcano was located. Ranger: The balance rocks and pinnacles at Chiricahua National Monument are eroded from layers of rhyolite, which is an igneous rock that has its start in a violent volcanic eruption an estimated 27 million years ago. Where was the volcano? You can see it behind me in the heart of the Chiricahua Mountain high country. You might see the eastern wall on the left hand side. When that volcano was erupting, an estimated 27 million years ago, instead of being huge lava flows like you might find in Hawaiian Islands, it was a gigantic ash eruption. Huge clouds of ash and gas were sent miles up into the atmosphere. As that material rained down back to earth, it covered an area of 1,200 square miles. You might compare it to the eruption at Mt. St. Helens in Washington State which occurred back in 1980. Geologists estimate that the eruption here in the Chiricahua Mountains was 1,000 times more powerful then what happened at Mt. St. Helens. After the gigantic ash eruption, the second stage of the volcanic activity were the huge pyroclastic flows, or if you like French, the nuée ardentes. These are clouds of ash and gas and rocks that come billowing down the sides of the volcano. They are extremely hot and very fast. So if anything was left standing after the direct ash fallout, it was probably wiped out by the nuée ardentes. Finally, so much material was blown out of the Turkey Creek Volcano, the top collapsed, leaving a gigantic hole or caldera, an estimated 12 miles across, and 5,000 ft deep. As that material settled it was still hot enough that the particles melted or welded together which created the grey rock known as rhyolite. Rhyolite is fun because it is composed of 98% silica. So if you find a freshly broken piece, it’s very sparkly, almost glassy in texture. That concludes part of our geology story here at Chiricahua National Monument. In part 2 we’ll discover how the layers of rhyolite were carved into the amazing balance rocks and pinnacles.
Music with images Ranger 1: Southeast Arizona is home to three National Park Sites, Chiricahua National Monument, Fort Bowie National Historic Site, and Coronado National Memorial. Each site offers unique opportunities to discover human history and the natural world. Southeast Arizona lies at a crossroads of four major ecosystems; Rocky mountains, Sierra Madres, and Chihuhuan and Sonoran deserts. These sky islands provide opportunities to explore and study richly diverse plant and animal life. Music with images Ranger2: Chiricauhua National Monument has a rich history and a vibrant natural foundation. You can learn about that rich history at Faraway Ranch where homesteaders tried to eak out a living off of the land. We also have a vibrant natural foundation. This monument was originally set aside in 1924 to protect the rich and awe inspiring geologic foundations that we affectionately call hoodoos or standing rocks. Music with images Ranger2: People visit Coronado National Memorial to find adventure and to explore new territories, often leaving with a sense of wonder at the story of the Coronado Expedition. You can explore above ground on our hiking trails, or below ground in a natural limestone cave. You might find yourself on top of Coronado Peak reflecting on the 4,000 mile trek made by Coronado and his men, and contemplating the hardships and difficulties of the expedition. Music with images Ranger4: In the arid Southwest reliable sources of water provide an obvious magnetism. Plants, animals, and people all rely on water for their survival. A stop here at Apache Springs provides an ideal spot to watch for wildlife, glimpse signs of early human uses, and image the many historic thirsts that were quenched at the cool, clear springs. Even though Apache Springs is a peaceful and refreshing spot, it was, at one time, the source of, and backdrop to, conflict between Anglos and Apache Indians more than a century ago. Music with images
Ranger Sharlot: Hello, and welcome to a Chiricahua National Monument ranger minute. I'm Ranger Sharlot and I'll be talking about the coatis today. Coatis are a great thing to see here, and they're one of my favorite animals.The coati, as they are sometimes called, is a relative of the raccoon, and seeing one while hiking the trails is a real treat.
Chiricahua National Monument is at the northern range for these coatis. If you were traveling to Mexico or Central America you might see many on your trip. But here in the monument the coatis have to travel farther to find enough food to live. So seeing one is a little bit more rare. Now what are these coatis traveling around rooting in the ground to eat? They're omnivores, which means that they'll eat both grubs and lizards, and berries and roots. So when they are traveling around in groups or family groups or troops, its usually females, males will travel alone. So if you are hiking our trails and you see a family group, or a troop, its usually females with their young under two years of age. Now these troops have to travel in our monument about 4 miles squared to find enough food to feed their family.
This trail, the Silver Spur Meadow Trail, is a favorite spot for one of those three groups of, or family troops, of coatis. Now I mentioned they like to dig for their food, and they're very lucky because they have some built in digging tools. They have very sharp claws, and they have a long snout, which lets them flip over rocks and dig through leaf litter very easliy so that they have easy access to their own buffet.
I mentioned that male coatis tend to travel alone. We had one male coati who liked to come to the campground because people were feeding him. Now coatis tend to be smart, and aren't too easily scared. So as long as you give them their distance, they'll let you watch them, which can be a really fun activity. However, if they start getting fed, just like all animals, they can get too aggressive. Here's Ranger Keith to talk about what happened in the campground.
Ranger Keith: Coatis look cute and cuddly, but they have sharp claws and sharp teeth, and are susceptible to rabies. This particular coatimundi got into the back of a pickup truck and started eating the food he found there. No amount of banging on the truck or yelling at him would get him out. He would bare his teeth and jump aggressively at the visitor. He had to be prodded out of the truck with a broom. When coatimundis get this aggressive we have to remove them, sometimes even dispatch them. We can't take a chance on them biting a visitor.
Ranger Sharlot: So as you can tell, the coati is a special critter to us. Its important to us to protect and preserve it. But we want you to be able to enjoy them as well. So come on out and hike one of the trails, and hopefully you too can see a coati, or maybe even a family troop. This has been a ranger minute from Chiricahua National Monument. Thanks for joining me.
Ranger Janet: Chiricahua National Monument lies within the Chiricahua Mountains, one of the Sky Islands of the Southwest. The Sky Islands are special habitats hosting plants and animals from 4 ecosystems, the Sonoran and Chihuahuan deserts, the Rockies, and the Sierra Madres. In addition to these living natural resources, the park contains an amazing array of rock formations, called the Wonderland of Rocks. At Chiricahua National Monument we value our visitors; we value the rock formations, and the plants and animals that live among them. We value the historic places, and the stories they tell.
When the Horseshoe Two Fire threatened the monument, we were afraid that all these valued resources would be destroyed. The situation seemed dire. Conditions in the Chiricahua Mountains were hot, dry, and windy. There had been 11 years of drought, so plants were dry. Fuel was plentiful, partly due to our former National Policy of Fire Suppression. There are few roads, and the terrain is steep. When fire entered the park on June 8, 2011, there were 3 priorities for fire management. Number one was to preserve life. The park was closed to protect the public and the employees. Fire fighter safety was paramount. The next priority was to protect structures, with an emphasis on irreplaceable historic buildings in the park. One tool used was wrapping the buildings with fire resistant materials. The third priority was resource protection whenever possible. Wildfire can burn intensely hot, causing every plant to burn completely. Backburning is a fire management tool that can limit the damage by selectively burning certain areas. This cooler, lower intensity fire takes out fuel that the wildfire might use. It can leave larger trees alive. It opens up the understory, which permits new growth to follow the fire. Fire management cannot prevent wildfire. The Horseshoe Two Fire seriously burned portions of the park. For people who know this particular landscape intimately, this loss of the big, old trees, is particularly hard. We know we will not see our beloved old landscape again in our lifetimes. Our centuries old trees will take several hundred years to replace. And yet, your lifetimes are only a snapshot in the history of these mountains.
There isn’t a right stage, or even a right plant community, in these fire-shaped ecosystems. These landscapes have experienced fires for eons. The Sky Island ecosystems developed with fires as intermittent events. Tree ring evidence shows that fire used to return every 15 years on average. These fires were mainly caused by lightning, though some were likely human caused. Each burned area will experience some kind of regrowth. What may grow will depend on the elevation, the intensity of the burn, nearby seed bed, the timing of the monsoons, the underlying soils, the time of year of the burn, and other local variables. Each fire changes the landscape for a time, a landscape continues to change as plants grow and animals move in. Historically, small, more frequent fires, maintain the grasslands at the entrance to the park. This time, burned out areas at the park entrance will experience rapid regrowth of grasses, just as they did in the past. Historically, fire pruned the river and creek areas, and limited the piñon and juniper forests to an open canopy. This permitted oaks and pines to grow, usually with some grass and low shrubs below. Our burnouts will also open up these areas for new growth beneath the trees that survived the fire.
The fire management actions helped protect areas of the park from intense wildfire. The cooler fires permitted some larger, older trees to survive. On this burn severity map, red indicates areas of greatest burn intensity, green represents low intensity burn. Note the mosaic pattern of the burn. The Horseshoe Two Fire, and the fire management strategies, created a new mosaic of burned, partly burned, and unburned areas in the park. Plants at different stages of growth provide a variety of food and shelter for animals. In this way, a mosaic landscape supports a larger diversity of plants and animals. We’re sad about the losses the park experienced. However, as Chiricahua National Monument emerges from the ashes, we find that the essences of our most precious resources remain. No one died in the fire, no structures were lost, the rocks remain, the animals still have many refuges, many trees still stand. New growth is coming with the changing seasons. Visitors to the park will have the incomparable opportunity to witness growth and change in this remarkable section of the Sky Islands. We hope you will return in the future.
Ranger Suzanne: Hello, I’m Park Ranger Suzanne, with part 2 in our Ranger Minute Series about the geology of Chiricahua National Monument. In part 1 we discussed the eruption of the Turkey Creek Volcano, an estimated 27 million years ago that blanketed this region with layers of ash. The ash and debris was still so hot when it settled, the particles melted together, and turned into the rock called rhyolite. In part 2 we are going to talk about how those layers of rhyolite were carved by ice, water, and other agents of erosion, to leave the incredible landscape of the balanced rocks and pinnacles we enjoy today. Let’s go take a look.
When the rhyolite was cooling it began cracking and jointing, both vertically and horizontally. We’re getting closer to the formation of the pinnacles. Roughly 10,000 years ago, or during days of the last Ice Age, the climate in this region was much cooler and wetter. Water seeped into those cracks and joints, froze, expanded, and melted. That cycle was repeated millions of times. Because not all areas of the ash were welded together at the same rates, the loose material began washing away, until finally we see the pinnacles at Chiricahua National Monument today.
You might have noticed how the balanced rocks and pinnacles are decorated with colors of green, orange, yellow, black. If you ask most people, they might guess those are different types of mosses. However, they are something very different. Those colors represent different species of lichens. Now a lichen is a living organism composed of two parts, there’s an algae and a fungus. The algae’s job is to take water and oxygen, photosynthesize, and create a food substance; whereas the fungus provides a shelter. Together they work in a positive relationship for both sides, which is called symbiosis. For the rock formations though, it is a two edge sword. They protect the rock, but they also produce a really weak acid, so they are actually etching away at the rock pinnacles as well. But the lichens are definitely one of the unique erosional features here at Chiricahua National Monument.
Now that you know how the balanced rocks and pinnacles were formed at Chiricahua National Monument, let’s go take a closer look at some of the other special erosional features.
Here along the Echo Canyon trail are two good examples of erosional features that work together. They’re called case hardening and tafonis. Case hardening occurs when water pulls silica minerals out from the interior rock of the pinnacles. They form a hard protective shell. Sometimes that shell gets broken, exposing the softer rock behind it. Water will then eat out at that softer rock forming a honey-comb series of rounded cavities, which are known by the Italian word, tafoni. Case hardening and tafoni, two great features along the Echo Canyon trail.
Chicken heads. What do chicken heads have to do with Chiricahua National Monument? Near the base of most pinnacles the rock surface has a knobby or plate-like protrusion, known as chicken heads. These miniature features contain remnant coatings of rock varnish and lichens, and have been case hardened to be more resistant to weathering than the surrounding fresh rock surfaces. There really are chicken heads at Chiricahua. (chicken squawk).
Is this the end to our geology story at Chiricahua National Monument? No, the good news is the story continues. The snows and ice of winter still seep into the cracks, freeze, expand, and break the rock. Winds of spring and fall gradually round the edges of the balanced rocks and pinnacles. Whereas the lichens etch themselves away as they create new soil. From the very violent volcanic eruption of the Turkey Creek Volcano 27 million years ago, to the carving by ice and water of the layers of rhyolite, we have a living work in progress of the amazing balanced rocks and pinnacles. I invite you to come visit this Wonderland of Rocks, and see the changes yourself.