"Owachomo Bridge" by NPS photo / Neal Herbert , public domain

Natural Bridges

National Monument - Utah

Natural Bridges National Monument is located about 50 miles (80 km) northwest of the Four Corners boundary of southeast Utah, in the western United States, at the junction of White Canyon and Armstrong Canyon, part of the Colorado River drainage. It features the thirteenth largest natural bridge in the world, carved from the white Permian sandstone of the Cedar Mesa Formation that gives White Canyon its name.

maps

Official visitor map of Natural Bridges National Monument (NM) in Utah. Published by the National Park Service (NPS).Natural Bridges - Visitor Map

Official visitor map of Natural Bridges National Monument (NM) in Utah. Published by the National Park Service (NPS).

Map of the U.S. National Park System. Published by the National Park Service (NPS).National Park System - National Park Units

Map of the U.S. National Park System. Published by the National Park Service (NPS).

Map of the U.S. National Park System with Unified Regions. Published by the National Park Service (NPS).National Park System - National Park Units and Regions

Map of the U.S. National Park System with Unified Regions. Published by the National Park Service (NPS).

Map of the U.S. National Heritage Areas. Published by the National Park Service (NPS).National Park System - National Heritage Areas

Map of the U.S. National Heritage Areas. Published by the National Park Service (NPS).

Map of Jacobs Chair, Piute Pass and Tables of the Sun Off-Highway Vehicle (OHV) Trails. Published by San Juan County.San Juan County OHV - Jacobs Chair, Piute Pass and Tables of the Sun

Map of Jacobs Chair, Piute Pass and Tables of the Sun Off-Highway Vehicle (OHV) Trails. Published by San Juan County.

Map of Peavine, Dark and Rig Canyons and Gooseberry Off-Highway Vehicle (OHV) Trails. Published by San Juan County.San Juan County OHV - Peavine, Dark and Rig Canyons and Gooseberry

Map of Peavine, Dark and Rig Canyons and Gooseberry Off-Highway Vehicle (OHV) Trails. Published by San Juan County.

Map 8 of the San Juan County Travel Plan in Utah. Published by San Juan County.San Juan County - Travel Plan - Map 8

Map 8 of the San Juan County Travel Plan in Utah. Published by San Juan County.

Map 7 of the San Juan County Travel Plan in Utah. Published by San Juan County.San Juan County - Travel Plan - Map 7

Map 7 of the San Juan County Travel Plan in Utah. Published by San Juan County.

Motor Vehicle Travel Map (MVTM) of Monticello Ranger District in Manti-La Sal National Forest (NF). Published by the U.S. Forest Service (USFS).Manti-La Sal MVTM - Monticello 2020

Motor Vehicle Travel Map (MVTM) of Monticello Ranger District in Manti-La Sal National Forest (NF). Published by the U.S. Forest Service (USFS).

Motor Vehicle Use Map (MVUM) of Monticello Ranger District in Manti-La Sal National Forest (NF). Published by the U.S. Forest Service (USFS).Manti-La Sal MVUM - Monticello 2020

Motor Vehicle Use Map (MVUM) of Monticello Ranger District in Manti-La Sal National Forest (NF). Published by the U.S. Forest Service (USFS).

Map of the San Juan County Off-Highway Vehicle (OHV) Travel Plan and Trail System. Published by San Juan County.San Juan County OHV - OHV Travel Plan and Trails

Map of the San Juan County Off-Highway Vehicle (OHV) Travel Plan and Trail System. Published by San Juan County.

https://www.nps.gov/nabr/index.htm https://en.wikipedia.org/wiki/Natural_Bridges_National_Monument Natural Bridges National Monument is located about 50 miles (80 km) northwest of the Four Corners boundary of southeast Utah, in the western United States, at the junction of White Canyon and Armstrong Canyon, part of the Colorado River drainage. It features the thirteenth largest natural bridge in the world, carved from the white Permian sandstone of the Cedar Mesa Formation that gives White Canyon its name. Three majestic natural bridges invite you to ponder the power of water in a landscape usually defined by its absence. View them from an overlook, or hit the trails and experience their grandeur from below. Declared a National Monument in 1908, the bridges are named "Kachina," "Owachomo" and "Sipapu" in honor of the ancestral Puebloans who once made this place their home. The entrance to Natural Bridges is at the end of UT 275, which is roughly 35 miles west of Blanding, Utah, on UT 95. Driving time from Blanding is roughly 45 minutes. Natural Bridges Visitor Center The Natural Bridges Visitor Center is typically open daily, 9 am to 4 pm. In winter, the visitor center is closed Tuesdays and Wednesdays and on certain holidays. Exhibits, a video presentation, and a bookstore are available. You can pay your entrance fee at the visitor center. The Natural Bridges Visitor Center is at the end of UT 275, which is roughly 35 miles west of Blanding, Utah, on UT 95. Driving time from Blanding is roughly 45 minutes. Natural Bridges Campground Camp in solitude among the juniper trees at Natural Bridges campground. The campground is conveniently located next to the visitor center off the main park road. Campsites are first-come, first-served and open year-round. Each site has a fire grill, picnic table, and tent pad, but no running water, electricity, or hookups. Standard Site 15.00 Fee per night at a standard Natural Bridges' campground site, all year. Group size is limited to 8 people and 1 vehicle. Senior/Access Rate 7.00 Discounted camping rates with valid Senior or Access passes. Fee per night at a standard Natural Bridges' campground site with valid pass, all year. Group size is limited to 8 people and 1 vehicle. Natural Bridges Campground Campsite featuring a picnic table and fire pit amongst the trees in Natural Bridges. Campsite in the Natural Bridges Campground Dark Skies at Owachomo Bridge a natural bridge at night with the Milky Way arcing overhead Natural Bridges National Monument was designated the world's first International Dark Sky Park in 2007 Sipapu Bridge Sipapu Bridge with a blue sky and clouds overhead Sipapu Bridge is one of the three massive bridges at the monument. Horse Collar Ruin a stone structure below a rock alcove Horsecollar Ruins are located near Sipapu Bridge Hiker at Kachina Bridge a hiker standing below a massive natural bridge Hiking trails link the three natural bridges at the monument. Owachomo Bridge a broad natural bridge with clouds in the sky Owachomo Bridge is one of the three natural bridges at the monument. Desert Varnish Ever wondered what those dark lines were on the rock walls of canyon country? These black, brown, and red streaks are called desert varnish. streaks of black desert varnish on a red rock wall Ephemeral Pools Ephemeral pools are a vital source of water in a parched desert. grasses growing in a ephemeral pool filled with water Celebrating 50 Years of Partnership Canyonlands Natural History Association celebrated its 50th anniversary of partnering with public lands in southeast Utah. Since its founding in 1967, CNHA has donated over $12 million to Southeast Utah Group parks and its other federal partners—the Bureau of Land Management and US Forest Service. Superintendent Kate Cannon hands a plaque to CNHA Executive Director Roxanne Bierman National Park Getaway: Natural Bridges National Monument Natural Bridges National Monument is a place of firsts. In 1908, President Theodore Roosevelt made Natural Bridges the first National Park Service site in Utah. The presidential proclamation states: “a number of natural bridges situated in southeastern Utah, having heights more lofty and spans far greater than any heretofore known to exist, are of the greatest scientific interest.” No one had seen such an impressive example of stream-eroded stone before. Dark sky full of stars above and below a natural land bridge. Monsoon Season Late summer is monsoon season on the Colorado Plateau. Afternoon thunderstorms are common - flash floods and lightning are possible. Learn more about this special time of year and how to plan for it. rainstorm over Canyonlands Arches National Park’s Free-Flowing Waters Visitors to Arches National Park experience natural free-flowing waters and have water to quench their thirst, thanks to an agreement between the National Park Service and the State of Utah. The sun sits just below the horizon behind Delicate Arch. Landbird Monitoring in Northern Colorado Plateau Network Parks, 2018 Because birds can be sensitive to habitat change, they are good indicators of ecosystem integrity. The Northern Colorado Plateau Network partners with the University of Delaware to assess breeding-bird species trends in three different habitats: low-elevation riparian, pinyon-juniper, and sage shrubland. Find out which species were increasing and declining at network parks as of 2018. Small, bright-orange bird with yellowish underfeathers. Surviving in the Desert In this arid land, plants and animals must adapt to constantly changing water availability. red blooms on cluster of claret cup cactus Veteran Story: William Bouley Bill Bouley served in the US Army for 20 years. Today he continues in public service as a Safety Manager for several parks and monuments in southern Utah. Bill Bouley, in uniform, with a helicopter in the background Wadeable Streams Monitoring at Natural Bridges National Monument, 2010–2018 Riparian areas are oases of life. To evaluate the health of riparian systems, the Northern Colorado Plateau Network monitors physical and biological attributes of wadeable streams. These indicators tell us about “normal” conditions and give park managers early warning of potential problems. Monitoring at Natural Bridges National Monument from 2010 to 2018 revealed how flood events caused changes in the channel, and how plants have responded. A hiker walks past juniper bushes toward a red rock arch. The Colorado Plateau The Colorado Plateau is centered on the four corners area of the Southwest, and includes much of Arizona, Utah, Colorado, and New Mexico. Hazy Fajada Butte, Chaco Culture National Monument NPS Geodiversity Atlas—Natural Bridges National Monument, Utah Each park-specific page in the NPS Geodiversity Atlas provides basic information on the significant geologic features and processes occurring in the park. Links to products from Baseline Geologic and Soil Resources Inventories provide access to maps and reports. [Site Under Development] large natural stone bridge Studying the Fate of Arches Park staff and scientists study geological change in the natural arches of Utah. Monitoring devices, like the crackmeter, measure vibration and expansion in arches that are actively eroding. The data collected could determine potential safety risks in the future. a park ranger looks at a computer with two large arches in the background Gnats In the late spring and early summer, swarms of tiny biting gnats often greet visitors to Utah national parks. These miniscule pests thrive in the scattered pinyon-juniper forests of southeast Utah. Reading Rock Markings If you travel the canyons of the American Southwest, you are sure to see figures carved or painted on rock faces. These include abstractions like spirals, dots and geometric patterns, or more recognizable forms like animals, humans, and handprints. They served to communicate among American Indian tribes throughout the centuries, and they continue to communicate today. depictions of bighorn sheep and riders on horseback pecked into a rock wall Animal-Transmitted Diseases in Southeast Utah Some diseases can be passed from animals to humans. Never approach wildlife and learn other ways to protect yourself from animal-transmitted diseases in Southeast Utah parks. Small brown and tan rodent standing up on hind legs, with soil and green vegetation around it. Biological Soil Crust of Southeast Utah Be careful where you step because the dirt is alive! This bumpy, lumpy, crust black soil is called biological soil crust and is made up of living organisms. bumpy black soil crust with lichen Lichens of Southeast Utah Those bright colors you may see on sandstone and biological soil crust are alive! Lichens grow in every size, shape, and color in Southeast Utah. scaly gray lichen growing on dark soil crust House Rules for Visiting Archeological Sites in Southeast Utah Visiting a Southeast Utah park? These parks contain sacred areas and ancestral homeland of over 30 traditionally associated Native American Tribes. Learn how to be a respectful guest at cultural sites with these house rules. Two people stand and look at a circular tower constructed out of rocks. What We’re Learning and Why it Matters: Long-Term Monitoring on the Northern Colorado Plateau Knowing which key natural resources are found in the national parks, and whether they're stable or changing, helps decisionmakers make sound choices. The Northern Colorado Plateau Network is building that knowledge. After more than ten years of monitoring, we've learned a lot about park ecosystems, how they're changing, and what they may look like in the days to come. Find out what we’ve learned and how it’s being used to help managers plan for the future. Man stands in a stream, looking down at a handheld gauge. Landbird Population Trends in the Northern Colorado Plateau Network, 2019 Because birds can be sensitive to habitat change, they are good indicators of ecosystem integrity. The Northern Colorado Plateau Network partners with the University of Delaware to assess breeding-bird species trends in three different habitats: low-elevation riparian, pinyon-juniper, and sage shrubland. Find out which species were increasing and declining at network parks as of 2019. Bald eagle Series: Geologic Time Periods in the Paleozoic Era During the Paleozoic Era (541 to 252 million years ago), fish diversified and marine organisms were very abundant. In North America, the Paleozoic is characterized by multiple advances and retreats of shallow seas and repeated continental collisions that formed the Appalachian Mountains. Common Paleozoic fossils include trilobites and cephalopods such as squid, as well as insects and ferns. The greatest mass extinction in Earth's history ended this era. fossil corals in a rock matrix Series: National Park Service Geodiversity Atlas The servicewide Geodiversity Atlas provides information on <a href="https://www.nps.gov/subjects/geology/geoheritage-conservation.htm">geoheritage</a> and <a href="https://www.nps.gov/subjects/geology/geodiversity.htm">geodiversity</a> resources and values all across the National Park System to support science-based management and education. The <a href="https://www.nps.gov/orgs/1088/index.htm">NPS Geologic Resources Division</a> and many parks work with National and International <a href="https://www.nps.gov/subjects/geology/park-geology.htm">geoconservation</a> communities to ensure that NPS abiotic resources are managed using the highest standards and best practices available. park scene mountains Series: Defining the Southwest The Southwest has a special place in the American imagination – one filled with canyon lands, cacti, roadrunners, perpetual desert heat, a glaring sun, and the unfolding of history in places like Tombstone and Santa Fe. In the American mind, the Southwest is a place without boundaries – a land with its own style and its own pace – a land that ultimately defies a single definition. Maize agriculture is one component of a general cultural definition of the Southwest. Permian Period—298.9 to 251.9 MYA The massive cliffs of El Capitan in Guadalupe Mountains National Park represent a Permian-age reef along the supercontinent Pangaea. The uppermost rocks of Grand Canyon National Park are also Permian. flat-top mountain Paleozoic Era During the Paleozoic Era (541 to 252 million years ago), fish diversified and marine organisms were very abundant. In North America, the Paleozoic is characterized by multiple advances and retreats of shallow seas and repeated continental collisions that formed the Appalachian Mountains. Common Paleozoic fossils include trilobites and cephalopods such as squid, as well as insects and ferns. The greatest mass extinction in Earth's history ended this era. fossil corals in a rock matrix Round-up Donations Add Up to Big Support If you tell our bookstore partner to "keep the change," those pennies lead to big support for park programs. A clerk ringing up a customer at Arches' bookstore Landbird Population Trends in the Northern Colorado Plateau Network, 2020 Because birds can be sensitive to habitat change, they are good indicators of ecosystem integrity. The Northern Colorado Plateau Network partners with the University of Delaware to assess breeding-bird species trends in three different habitats: low-elevation riparian, pinyon-juniper, and sage shrubland. Find out which species were increasing and declining at network parks as of 2020. Small beige bird with black beak and feet, brown back. Climate Smart Conservation Planning for the National Parks In response to climate change, park managers are having to rethink how they plan for the future. Climate Smart Conservation is a process that can help managers achieve goals in the face of coming changes. Under this framework, scientists and managers use their collective knowledge to anticipate problems and be proactive, rather than reactive. Pika with a mouthful of grass Monitoring From Space: Using Satellite Imagery to Measure Landscape Conditions on the Ground Scientists from the Northern Colorado Plateau Network travel thousands of miles each year to collect data on plants, soils, and water across network parks. But it would be impossible to cover every square inch of the Northern Colorado Plateau with boots on the ground. Instead, we simultaneously monitor the parks with boots in space—satellite data that provide information at a much broader scale. Satellite and Earth in space Responding to Climate Change in the Southeast Utah Parks This paper describes how the Southeast Utah Group of parks is responding to climate change. The paper summarizes expected future climate conditions compared with a 20th Century baseline. It describes the foundation of our work within the Climate Smart Conservation framework adopted at our initial workshop in December 2018. A photograph of a grassland, containing some shrubs. Localized Drought Impacts on Northern Colorado Plateau Landbirds Birds of the desert southwest, a climate-change hotspot, are among the most vulnerable groups in the US. To help park managers plan for those changes, scientists evaluated the influence of water deficit on landbird communities at 11 national parks in Utah and Colorado. The results will help land managers to focus conservation efforts on places where certain species are most vulnerable to projected climate changes. A man wearing a clipboard looks through binoculars at dawn in field of sagebrush Series: Intermountain Park Science 2021 Integrating Research and Resource Management in Intermountain National Parks Group of National Park Service staff and volunteers standing in front of a desert canyon.
Natural Bridges National Park Service U.S. Department of the Interior Natural Bridges National Monument Visitor Guide Natural Bridges sits high on Cedar Mesa, 6,500 feet above sea level. Intermittent streams have cut two deep canyons and three massive bridges in sandstone formed from what was once the shore of an ancient sea. At each of the bridges, trails descend into the canyons from the loop road. A longer trail meanders along the canyon bottoms through oak and cottonwood groves (shown above), connecting the three bridges in one loop hike. General Information Scenic Drive The scenic drive is open year-round. This paved, nine-mile loop provides access to all the bridges. Each may be viewed by walking a short distance to an overlook. An archeological site may also be viewed from an overlook along the scenic drive. Visitor Center The visitor center is open 9 am to 4:30 pm daily, with extended hours during summer. The building is closed Thanksgiving, Christmas, and New Year’s Day. Exhibits, a video presentation, and bookstore are available. Entrance Fees (good for seven days) More Information Natural Bridges National Monument HC 60 Box 1 Lake Powell, UT 84533 (435) 692-1234 www.nps.gov/nabr $10 Vehicle $5 Individual (walk-in, bicycle, motorcycle) Weather Month Average High Average Low Average Precipitation Campground The 13-site campground is open year-round, first-come, first-served. Fee is $10 per night. Sites will accommodate up to eight people and one vehicle. There is a 26-foot length limit. Each site has a grill, picnic table and tent pad. Gathering firewood is prohibited. Evening programs are offered in summer (check bulletin boards for schedules). More campgrounds are available outside Natural Bridges. Pets Pets are allowed on paved trails and roads but must be leashed at all times. Pets are not allowed on hiking trails or in the backcountry. J F M A M J J A S O N D 39 17 45 22 51 26 60 32 71 40 81 49 90 58 86 56 77 49 63 37 50 27 40 19 .97 .95 1.22 .83 .67 .57 1.45 1.59 1.07 1.48 1.11 1.28 Visitor Safety • Check trail conditions at the visitor center before hiking. • Drink at least one gallon (4 L) of water each day. • Remain in one place if you become lost or separated from a group. • During a lightning storm, avoid lone trees, cliff edges and high ridges. Return to your vehicle if possible. • Flash floods can occur without warning. Never cross a canyon that is flooding. • Be careful near cliff edges, especially when rock is wet or icy. • Do not climb on the bridges; it is both dangerous and illegal. • Always carry a map, adequate clothing, and a flashlight. Caring for the Canyons Natural Bridges preserves habitat for a variety of plants and animals. Visitors may see mule deer browsing, hear the falling notes of a canyon wren, or smell the sweet aroma of spring wildflowers. To guard these experiences for future generations, please observe the following regulations: • Leave water for wildlife: do not disturb pools or intermittent streams by bathing or swimming. • Do not enter archeological sites, remove artifacts, or touch rock art. • Camping is permitted only in the campground. • Vehicles and bicycles must remain on designated roads. • Vehicles may not be left unattended overnight along the loop road. Cryptobiotic soil crust • Pets are not allowed on hiking trails. • Protect cryptobiotic soil crusts by staying on trails. NORTH CAN YON Hiking Trails EE R Overlook/ Paved road CANYON W D Hiking Trail Bridge view Sipapu Bridge Intermittent Stream Horsecollar Ruin Overlook H ITE Bridge View Drive 9mi 14.5km 0.6 on w e- Visitor Center 6505ft 2001m 0.8 Tr a il ay 0.3 p Loo 2.3 WHITE NYON CA "Knickpoint" Pour-off Bridge view 1. 2 1.0 0.7 Kachina Bridge op ST Lo M AR ay e-w TUWA N NYO CA Owachomo Bridge Kachina Bridge Trail Hiking Times & Distances Round Trip Elevation (mi/km) Change (ft/m) Hiking Time Bridge Hikes Sipapu 1.2/1.9 500/152 1 hr Kachina 1.4/2.3 400/122 1 hr Owachomo 0.4/0.6 180/55 30 min 8.6/13.8 500/152 4 to 6 hrs 5.6/9 500/152 2 to 4 hrs Kachina/Owachomo 5.4/8.7 400/122 2 to 4 hrs Horsecollar Ruins 0.6/1.0 30/9 30 min Loop Hikes Hikers make their way down the trail to Sipapu Bridge. Horsecollar Ruin earns its name from the shape of the doors to these granaries. N R 0.2 Sipapu/Kachina YO 3.0 O N G Tr a il Bridge view Sipapu/Owachomo CAN on Kachina is a massive bridge and is considered the "youngest" of the three because of the thickness of its span. The relatively small size of its opening and its orientation make it difficult to see from the overlook. The pile of boulders under the far side of the bridge resulted from a rock fall in 1992, when approximately 4,000 tons of rock broke off the bridge. As you descend the switchbacks, notice the “Knickpoint” pour-off in Armstrong Canyon below to your left. During floods, this spout sends a muddy red waterfall plun
Natural Bridges National Park Service U.S. Department of the Interior Natural Bridges National Monument Archeology Listen carefully while you stand at the rim above Horsecollar Ruin. Can you hear voices in the wind? Listen for the rhythmic grinding of mano on metate as corn is turned to flour. Turkeys cackle in a pen while dogs bark. Children laugh as they play among the rocks. The soft song of a potter at work is interrupted by the shouts of a returning hunting party carrying a bighorn sheep. The sharp pecking sound you hear may be an artist or shaman carving a new petroglyph. Migrations: A Hopi Perspective Pictograph representing the Migration of the People Migrations: An Archeological Perspective “The Hopi today live on or near three mesas in Northeastern Arizona. In the past they lived other places as well. Their history is a story of many migrations—the movements of clans and villages. The ancestors of the Hopi, called Hisatsinom, once inhabited many parts of the American Southwest, including the Natural Bridges area. Archeologists often refer to them as ancestral Puebloans. Throughout their migrations the Hisatsinom clans left markers (pictographs and petroglyphs) to show where they had been. Often they left artifacts from special religious societies in place and they left markings on walls to indicate that particular ceremonies had been performed before the people left. Religious society leaders gave permission for such sacred symbols to be put on the walls. These images make up much of the ‘prehistoric’ rock art now enjoyed by visitors to the Southwest.” Archeologists believe that the ancestral Puebloans occupied this area during three distinct periods. Between these occupations were periods of 200 to 300 years when few people, if any, lived here. Were these the migrations Mr. Hamana refers to? but wild plants and game made up more of the diet. The bow, arrows and pottery were not made yet, but spears and baskets were. Homes were small, slab-lined “pithouses.” A.D. 200 to 400 While hunters and gatherers may have passed this way earlier, settlement first occurred during this period. Corn was farmed, Mr. Walter Hamana, Hopi Elder 1992 visit to Natural Bridges rock art sites A.D. 650 to 725 After 250 years of abandonment, people returned to Cedar Mesa. They brought beans, and pottery to cook them in. The cultivation of beans enriched the soil with nitrogen which growing corn had depleted. The bow and arrow appeared at this time. Larger homes of connected rooms above ground replaced pithouses as populations grew. A.D. 1060 to 1270 Three hundred years after their ancestors left, the farmers returned. They built homes of sandstone masonry or mud-packed sticks, Connections and Abandonment Styles of masonry, ceramic decoration and other artifacts suggest that the people here were related to those of the Mesa Verde region to the east. Influences are clearly evident from the Kayenta region to the southwest and the Fremont culture to the north. Like these people, the inhabitants of Cedar Mesa left this area for the last time around A.D. 1270. Theories and speculation surround this great abandonment. Some would suggest that raiding nomads forced the ancestral Puebloans first into the cliffs for defense, then out of Protection: Why? How? both on the mesa tops and in alcoves in the cliffs. South-facing caves provided passive solar heating and cooling. They often chose sites near seep springs where water could be found. The last canyon dwellers left about A.D. 1270. the region entirely. Little evidence is found to support this theory and it is believed that groups like the Navajo, Apache, Ute and Paiute did not arrive until well after the abandonment. Another theory suggests that the people had overused the fragile soil and timber resources. This would have caused increased erosion and reduction in crops, wild game and water supplies. Still others believe that the people simply reached the end of their migrations when they arrived where their descendants, the Hopi, Zuni and Rio Grande peoples, live today. These places are critically important to all of us. Mr. Hamana and others have their roots here. Hundreds of years of their history are written on the stone walls of these canyons. We frequently see these ruins and rock art only as curiosities, but perhaps they can teach us about our history and our future. enforced federal and state laws, notably the Antiquities Act of 1906 and the Archeological Resources Protection Act (ARPA) of 1979. These laws provide substantial fines and jail terms for site damage or the removal of even one small artifact such as a piece of pottery or part of an arrowhead. It is easy to distance ourselves from the ancestral Puebloans through time and technology. After all, what can we learn from a “primitive” culture such as theirs? Quite simply, they were people with the same basic needs as people today. They faced hunger, population growth, floods, drought and war
Natural Bridges National Park Service U.S. Department of the Interior Natural Bridges National Monument Geology Stand for a moment at an overlook. Nothing in the scope of your vision moves. Strain your ears for a sound; silence alone greets them. The desert landscape seems eternally unchanging. But stay a moment longer and a small animal sends a pebble clattering down the slickrock. Stay for an hour and the wind picks up, blowing sand and dust against you. Tomorrow a thunderstorm may send a flood twisting down the course of White Canyon. In one month, several tons of rock may thunder down from Kachina Bridge as it did in June of 1992 when 4,000 tons fell from the bridge. If you return next year, Owachomo Bridge may no longer be standing. The momentary stillness of Canyon Country is deceptive; the same processes which formed the seemingly eternal landscape you are enjoying today are still at work, continually changing the face of the earth. Before the Bridges Current Slip Face Formation of the crossbedded Cedar Mesa Sandstone Bridges and Arches Bridges are formed by the erosion of meandering streams. If you had visited this area 260 million years ago, you would be standing on the dazzling white beach of a sea which covered eastern Utah during the Permian geologic period. You may have noticed the sweeping lines, known as crossbedding, that pattern the white sandstone. Crossbedding represents the down-current face of a sand dune, down which sand slips as the dune advances under the force of wind or water. Geologists debate whether the Cedar Mesa Sandstone formed under water or along the shore as windblown dunes. You can see ripple marks forming today in the mud left in the canyon bottoms by receding flood waters. Although the waters of the warm Permian Sea supported abundant life, fossils are rare at Natural Bridges. If you have ever stood on the ocean shore, you may know why. You may have noticed that arches stand on the skyline whereas bridges form in the bottoms of deep canyons. Once water dissolves the cement between the grains of sand in a narrow fin of sandstone, frost wedging and gravity begin to work. While seeping moisture and frost shape arches, running water carves natural bridges. As the curving meanders of streams carved down into the sandstone, they undercut the canyon walls and bent back upon themselves until only a thin fin of stone separated them. Flash floods periodically pounded against weak spots formed by the soft siltstone layers in the sandstone. Eventually, the water cut through the narrow neck of the meander, forming a A beach is classified as a high energy environment, where grains of sand continually grind back and forth with each sweep of the tide. Few organisms can survive such rough treatment; thus, few make it their home. Any plant or animal remains swept ashore soon wear away. If you examine the Cedar Mesa Sandstone with a hand lens, you may see that some of the sand grains are actually fragments of fossils. One type of fossil is abundant in the streambeds of White and Armstrong canyons: petrified wood. This wood washes out of the Chinle Formation, found high above the Cedar Mesa Formation. When the trees died, they fell into stagnant swamp water which prevented their decay. Eventually, silica derived from volcanic ash replaced the wood, preserving its grain in stone. natural bridge. At first each bridge is thick and massive, as is Kachina Bridge, but as erosion attacks them on all sides, the bridges become more delicate (as with Owachomo Bridge) and eventually collapse. How Old is Old? We know that compared to the other bridges in the monument, Owachomo is the oldest bridge, but how old is old? Geologically speaking, the bridges themselves are relatively recent and short-lived occurrences. Since sandstone erodes at different rates (more weathering occurs when the climate is wet than during times of aridity), the exact age of the bridges is difficult to determine. We do know that ten million years ago the Colorado Plateau was flat and featureless. When the last glacial period ended 18,000 years ago, glacial melt and increased rainfall speeded the erosion of canyon country. A wet climate between 900 and 4,000 years ago probably began the erosion of most spans; the largest spans are believed to be over 5,000 years old. The Many-Colored Landscape Southeastern Utah is a land not only of texture, but of radiant color. In the hills, pale greens mingle with grey and white, and mesas glow with the red of the setting sun. Much canyon country color derives from the presence of iron in different combinations with oxygen. The original sediments may have been drab, but they contained a small percentage of iron-bearing minerals. Groundwater later weathered these minerals, and oxygen rusted the iron a brilliant orange-red. Without enough oxygen, iron turns green. When iron combines with both hydrogen and oxygen, it becomes yelloworange limonite. Beneath the multi-colored mesa

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