Arizona National Parks: Petrified Wood and Volcanoes

South Rim, Grand Canyon, Arizona
View from the South Rim, Grand Canyon, Arizona. Saibal / Getty Images

Arizona's national parks reveal the austere beauty of desert landscapes, blending ancient volcanoes and petrified wood with the adobe architecture and innovative technology of the regions' Ancestral People.

National Park Service Map of Arizona National Parks
Arizona's National Parks Map. National Park Service

The U.S. National Park Service manages or owns 22 different national parks in Arizona, including monuments, historic trails, and sites attracting over 13 million visitors each year. This article describes the most relevant parks and their cultural, environmental and geological significance

Casa Grande Ruins National Monument
Ruins of the Casa Grande Ancestral Pueblo site at Casa Grande Ruins National Monument. Richard Cummins / Corbis Documentary / Getty Images

The Casa Grande Ruins are located in the Sonoran Desert of south-central Arizona, near Coolidge. The ruins represent a Hohokam (Ancient Sonoran Desert) people's farming community, a village built by early farmers of Mesoamerican-influenced culture that flourished between 300 and 1450 CE. The "Great House" for which the ruins are named is a late addition to the village, a four-story, 11-room building constructed around 1350 CE, one of the largest prehistoric structures ever built in North America. It was built of caliche, a natural combination of clay, sand, and calcium carbonate that was puddled into mud consistency and then used as construction material—when dry it is hard as concrete. The structure could have been a residence, a temple, or an astronomical observatory—no one really knows what its purpose was. 

Long before the Great House was built, life along the rivers in the desert grew difficult to sustain as the population increased, and the people started building irrigation canals around 400–500 CE. There are hundreds of miles of prehistoric irrigation canals around the Gila River, as well as the Salt River in Phoenix and the Santa Cruz River in Tucson, which allowed people to grow corn, beans, squash, cotton, and tobacco outside of the immediate valley. 

Grand Canyon National Park
Colorful sunset overlooking the Colorado River deep in the Grand Canyon. Dean Fikar / Moment / Getty Images

Located in north central Arizona, the Grand Canyon is one of the United State's most famous natural resources, a great gash in the ground that follows 277 river miles of the Colorado River, and is 18 miles wide and a mile deep. The geology represented at the base is igneous and metamorphic rock laid down nearly two billion years ago, with stacked sedimentary layers on top of that. Beginning about 5-6 million years ago, the Colorado River began carving out the river valley and creating the canyon. Human occupation in and near the canyon began about 10,000 years ago or more, evidenced by dwellings, garden sites, storage facilities, and artifacts. Today, the ruins are important to Havasupai, Hopi, Hualapai, Navajo, Paiute, White Mountain Apache, Tusayan, Yavapai Apache, and Zuni groups in the U.S. southwest and Mexican northwest.

Although today millions of people visit the Grand Canyon each year, its earliest European explorers in the mid-19th century mapped the canyon as a "great unknown," an empty space on maps of the day. The first federal government-funded expedition was in 1857-1858, led by First Lieutenant Joseph Christmas Ives of the U.S. Army Corps of Topographical Engineers. He started up the Colorado river with a 50-foot long sternwheel steamboat which crashed before he got into the canyon. Dauntless, he continued up the river in a skiff and then on foot to what is now the Hualapai Indian Reservation. He reported that the region was "altogether valueless," but "lonely and majestic," doomed to be forever unvisited and undisturbed.

Montezuma Castle National Monument
Montezuma Castle National Monument preserves dwellings built by the Southern Sinagua culture between 1100 and 1425 CE. Ivan Vieito / iStock / Getty Images

Montezuma Castle National Monument, near Camp Verde in central Arizona, is one of the very first of the U.S. National Monuments, declared by President Theodore Roosevelt in 1906. The monument preserves archaeological elements of the Southern Sinagua culture between 1100 and 1425 CE. These elements include the cliff dwellings (such as the Castle), pueblo ruins, and pit houses. The park also features the Montezuma Well, a collapsed limestone sinkhole from which an irrigation ditch was first constructed about 1,000 years ago. The Montezuma well contains organisms found nowhere else in the world which have evolved in response to the unique mineralization of the water. 

The monument is set in the Sonoran desert, and as such, it includes nearly 400 species of plants such as mesquite, catclaw, and saltbush adapted to life in the arid environment. The park is interwoven by microhabitats along the river corridors, with plant life of monkeyflower and columbine, sycamore and cottonwood. Two hundred species of birds reside in the park for some part of the year, including Rufous hummingbirds that pass through on their way from Alaska to Mexico every year. 

Navajo National Monument
Keet Seel ruins, Navajo National Monument, Arizona. A Welsh Lad / E+ / Getty Images

In the northeastern corner of the state, near Black Mesa, lies Navajo National Monument, created in 1909 to protect the remains of three large pueblos built between 1250-1300 CE named Keet Seel, Betatakin, and Inscription House. Built within large natural alcoves in the rock face, the houses were the homes of the Ancestral Pueblo people who farmed the canyon's stream terraces.

In addition to the large pueblo villages, archaeological evidence documents human use of this region over the past several thousand years. Hunter-gatherers first lived in these canyons, then the Basketmaker people about 2,000 years ago, and then the Ancestral Pueblo people, who hunted wild game and grew corn, beans, and squash. Modern tribes descending from the inhabitants include Hopi, Navajo, San Juan Southern Paiute, and Zuni, and the park is surrounded by the Navajo Nation, who have lived here for hundreds of years. 

Organ Pipe Cactus National Monument
Clearing spring storm at the Ajo Mountains in Organ Pipe Cactus National Monument. Ron Thomas / E+ / Getty Images

Located near Ajo, at the border between Arizona and the state of Sonora in Mexico, Organ Pipe Cactus National Monument is an International Biosphere Reserve established in 1976 to study and preserve the extraordinary collection of plants and animals found in the Sonoran desert. Thirty-one different species of cactus, everything from the giant saguaro to the miniature pincushion, can be found here, highly developed to thrive in the arid environment. 

The cacti bloom year-round in a variety of yellow, red, white, and pink; in spring, gold Mexican poppies, blue lupines, and pink owl clover add to the display. Organ pipe cacti live over 150 years and only open up their white creamy flowers at night after their 35th year. Animals found in the park include Sonoran pronghorn antelope, desert bighorn sheep, mountain lion, and bats. About 270 bird species are found in the park, but only 36 are permanent residents, including Costa's hummingbirds, cactus wrens, curve-billed thrashers, and Gila woodpeckers.

Petrified Forest National Park
Petrified wood on Long Logs Trail, Petrified Forest National Park, Colorado Plateau, Arizona. Witold Skrypczak / Lonely Planet Images / Getty Images

Petrified Forest National Park in central eastern Arizona has two geological formations: the Late Triassic Chinle Formation, and the Mio-Pliocene Bidahochi Formation. The petrified wood logs found throughout the park are conifers named Araucarioxylon arizonicum, a Late Triassic fossil pine tree which grew about 225 million years ago. The colorfully striped Painted Desert badlands are of the same period, composed of bentonite, a product of altered volcanic ash. Mesas and buttes in the park are other features created by erosion. 

About 200,000 years ago, an ancient flood moved the logs of the conifers into an ancient river system along with massive amounts of sediment and debris. The logs were buried so deeply that oxygen was cut off and decay slowed to a centuries-long process. Minerals including iron, carbon, manganese, and silica dissolved from volcanic ash were absorbed into the cellular structure of the wood, replacing the organic material as it slowly broke down. The result is petrified wood made up of almost solid quartz—clear quartz, purple amethyst, yellow citrine, and smoky quartz. Each piece is like a giant rainbow-colored crystal, often sparkling in the sunlight as if covered by glitter.

Saguaro National Park
Saguaro giant Cacti (Carnegiea gigantea) in Saguaro National Park. Michele Falzone / Photolibrary / Getty Images

Saguaro National Park, near Tucson, Arizona is home to the nation's largest cactus and the universal symbol of the American West: the giant saguaro. The varied elevations within the park allow for microclimates that support a great variety of different species. There are 25 different species of cactus alone in the park, including fishhook barrel, staghorn cholla, pink-flower hedgehog, and Engleman's prickly pear. 

The majestic saguaro cacti are the stars of the park, great accordion-pleated trees towering overhead. The pleats allow the cactus flesh to soak up and store water, swelling and spreading open after a heavy rain, and contracting as the water is used during the long dry periods. Saguaro cacti are host to a great variety of animals. The gilded flicker and Gila woodpecker excavate nest cavities inside the pulpy flesh, and after a woodpecker abandons a cavity, elf owls, purple martins, finches, and sparrows may move in.

Sunset Crater Volcano National Monument
The natural beauty of the Sunset Crater Volcano in Flagstaff, Arizona. Rauluminate / iStock / Getty Images

Near Flagstaff in north-central Arizona is Sunset Crater Volcano National Monument, which preserves the youngest, least-eroded cinder cone of 600 cones in the San Francisco Volcanic field, a reminder of the Colorado Plateau's most recent volcanic eruption. The hundreds of volcanic features in the landscape were created by a series of eruptions that took place around the year 1085 CE, and were witnessed by the Native American tribes living here.

Much of the surface of the park is covered by lava flows or deep volcanic cinder deposits, broken up by small islands of pine and aspen trees, desert shrubs and other evidence of the park returning to life. Plants such as Penstemon clutei (Sunset Crater penstemon) and Phacelia serrata (saw phacelia) are short-lived wildflowers found only on cinder deposits within the San Francisco Volcanic Field. These provide a unique opportunity to see and study eruption dynamics, change, and recovery in an arid environment. 

Tuzigoot National Monumen
Tuzigoot National Monument is covered in a rare snowfall on New Year's Day, 2015, an ancient Sinagua Pueblo ruin in Clarkdale, Arizona. Doug Van Gausig / iStock / Getty Images

Tuzigoot National Monument, located near Clarkdale in central Arizona, is an ancient village—pueblo—built by a culture known as the Sinagua. Tuzigoot pueblo (the word is an Apache word for "crooked water") has 110 rooms in an apartment block with second and third stories, and they were occupied from the time that the first buildings were built about 1000 CE until about 1400, when the Sinagua left the area. The Sinagua were farmers who maintained trade connections with people from hundreds of miles away. 

Although the climate is arid, with less than 12 inches of rainfall annually, the region attracted settlement because of several perennial streams that thread their way from upland headwaters to the Verde Valley below. The park has a striking vista of lush riparian ribbons of green and the Tavasci Marsh within an otherwise parched landscape of juniper-dotted hills, leading to a great diversity of plant and animal life. 

Wupatki National Monument
Tourists explore the red orange Wukoki Pueblo Ruins of Wupatki National Monument, inhabited by the Sinaqua Indians from about 1100 to 1250 CE. W Holden / E+ / Getty Images

Wupatki National Monument, located near the Painted Desert and Flagstaff, includes the remains of what was, 800 years ago, the tallest, largest, and perhaps richest and most influential of all the pueblos in the Four Corners region. The Ancient Puebloans built their towns, raised families, and farmed and thrived. The local environment has juniper woodlands, grassland, and desert scrub plant communities, with broad vistas of mesas, buttes, and volcanic hills. 

Most of the geology at Wupatki is made up of sedimentary rocks from the Permian and Early to Middle Triassic period of 200,000 million years ago and older. It is also home to "blow holes" where the earth inhales and exhales puffs of wind depending on the current temperature and humidity.