Hiking Trails in Phoenix - Scottsdale - Mesa

Phoenix - Scottsdale - Mesa

Phoenix - Scottsdale - Mesa

Camelback Mountain: Cholla Trailhead

Lost Dutchman State Park

McDowell Mountain Regional Park: Dixie Mine Trailhead

McDowell Sonoran Preserve: Gateway Trailhead

McDowell Sonoran Preserve: Lost Dog Wash Trailhead

McDowell Sonoran Preserve: Sunrise Trailhead

McDowell Sonoran Preserve: Tom's Thumb Trailhead

Superstition Wilderness: Canyon Lake Trailhead

Superstition Wilderness: First Water Trailhead

Superstition Wilderness: Hieroglyphics - Lost Goldmine Trailhead

Superstition Wilderness: Peralta Trailhead

Phoenix - Scottsdale - Mesa - Geology


This article was generously supplied by Tom Kollenborn (c) 1997, renowned author and historian of the Superstition Wilderness

The geology of the Superstition Wilderness Area can be divided into three distinct categories. They include (1) rock type, (2) structure and (3) process.

The rock type consists primarily of extrusive igneous rocks associated with vulcanism. Structure is consistent with the type of landforms that result from volcanic action and tectonic activity. The process is related to mass wasting, erosion, faulting, mountain-building and volcanic activity. All three of these categories contributed to the rugged and spectacular beauty of the Superstition Wilderness Area we enjoy today.

The western portion of the wilderness area is dominated by igneous rock whose origin is primarily volcanic action. There are examples of sedimentary and metamorphic activity within the boundaries of the wilderness, however this activity is very limited.

There are Pre-Cambrian granites in a few isolated areas of the wilderness that were formed from intrusive igneous rocks.

Intrusive rocks are formed from molten magma cooling beneath the surface of the earth. In other words, the melt (magma) was not exposed to the atmosphere while it cooled. Eventually intrusive rocks are exposed on the earth's surface by erosion.

Erosion is the wearing away process of the earth's surface by wind, water and ice. These intrusive rocks can be found along the First Water Road and the Apache Trail (SR 88) northeast of Apache Junction. Granite diabase can be found east and south of the IV Ranch.

Common volcanic landforms found in the area are calderas, blister cones, lava flows, mudflows and ash deposits. Dacite, Andesite, Rhyolite, Tuff and Breccia are the common igneous rocks found in the area.

During a more recent eruptive geologic period (3 million years ago) many erosional remnants were capped with black basalt from the Black Mesa, Willow Springs and Florence caldera systems. Most of these large lava flows were the results of fissures, cracks in the earth, not volcanoes.

North of the wilderness, sedimentary deposits of volcanic debris have been deposited by the action of running water during the eruptive stage. Many of these deposits have graded bedding, which is sometimes indicative of stream deposited gravel. In this case, the water was produced by volcanic steam and vented during the eruptions.

It was very hot and viscous mudflows that formed the graded bedding deposits near Canyon Lake.

Along the Apache Trail, where the road crosses the Superstition Mining District between Superstition Mountain and the Goldfield Mountains, other rock types are prevalent.

These include coarse-grain granites, indurated conglomerates and breciated granites. Arkosics can also be found in this area. Faulting prevails throughout the area. Small stringers of quartz that were caused by epithermal and hydrothermal action intruded the rocks in the Goldfield area. These small veins carry small quantities of gold.

Near Roosevelt Lake, but still within the confines of the wilderness area, true sedimentary rocks can be found. These rocks are ancient Pre-Cambrian sediments of the Apache Group found in the upper Salt River Canyon some forty miles northeast of Globe, Arizona. This group includes limestone, sandstone, and conglomerates.

Outcrops of ancient metamorphics can be found in one isolated area near the southern boundary of the wilderness. These rocks include schist, marble and slate. The Hewitt Canyon metamorphics are commonly intermingled with volcanics. Most of this intermingling is the results of intrusion by igneous rocks. Severe tectonic activity and movement of the earth's crust was caused by the intrusion.

This area appears to be the extreme eastern limits of the Superstition Mountain eruptive field.

The geology of the Superstition Wilderness Area and adjacent areas are very complex. For the most part the region has a tremendous amount of geological diversity.

The actual wilderness area has never proved to be highly mineralized near the surface. Deep-seated deposits of minerals still remain elusive to the mod- ern prospector or miner. Major mining companies have avoided the area for al- most a century. Extensive core drilling was done near the Woodbury Trailhead in the 1970's with no major mineral discoveries being made or announced.

Some geologist believed Superstition Mountain is the remains of a large collapsed caldera. This caldera has experienced three basic geologic stages in its evolution.

The first stage involved the formation of dacite cones on a granitic basement complex more than twenty-nine million years ago. This resulted from magma intruding the granite and depositing basalt and ash in the forms of cinder cones and lava flows. The alternating layers of ash and basalt helped form the present mountain we call Superstition. After millions of years of eruptions the area was leveled by erosion.

After a long period of inactivity the magma below the earth's surface began to recede leaving a massive cavity below the crust of the earth. The second stage in the formation of Superstition Mountain then occurred. The entire area collapsed into the cavity resulting in a huge caldera some seven miles in diameter.

As parasite cones developed within the caldera and began to issue forth ash, deposition occurred over some one thousand square miles. Remnants of these eruptions remain visible today. Picket Post Mountain, west of Superior, is a classic example of deposition remnant.

As the volcanic action of the second stage began to subside, the third stage of the mountain's evolution began.

Uplift and subsidence were both common during this period. However, uplift dominated the development scene for several million years resulting in the familiar landmark we know today as Superstition Mountain. Origi- nally the mountain was some three to four thousand feet higher, but water erosion reduced it to its present configuration and size.

The deeply incised canyons and large alluvial fans are landforms resulting from millions of years of erosion. This is the basic geologic evolution as reported by Dr. Michael Sheridan, Vulcanologist at Arizona State University from 1970-1989. To- day there are other theories as to how Superstition Mountain formed and the other geologic formations in the area. So far none of the theories are conclusive.

Geologists have studied other theories as to how Superstition Mountain formed. The degree of uplift or resurgence as reported by Sheridan is in direct contrast with the findings of some U.S.G.S. geologist have found. Some geologist report Weavers Needle was formed the same way Superstition Mountain.

Weavers Needle was formed as an erosional remnant. Some geologist believed this theory is applicable to Superstition Mountain. However there is not sufficient geologic evidence to support the theory Weavers Needle is a volcanic plug.

The geology of the Superstition Wilderness Area is a fascinating study of igneous rock and their various formations. The rocks of the western portion of the Super- stition Wilderness are eruptive igneous in origin. These rocks formed a wonderland of beautiful volcanic formations deposited between 3 - 25 million years ago.

We can only marvel at the beautifully textured and varied landscape the Superstition Wilderness Area has provided for us. For us, the future lies in protecting this region for our grandchildren to enjoy and marvel at.

Phoenix - Scottsdale - Mesa - Wildlife


Wildlife of the Superstition Wilderness - Tonto National Forest

While the Sonoran Desert can seem desolate and inhospitable, many animals call this area home. Through physical and behavioral adaptation, these animals are able to tolerate the extreme temperatures and harsh conditions of the Sonoran ecosystem.

Mammals of the Sonoran Desert

Mammalian species are found throughout the Sonoran desert and are characterized by both the presence of fur and the ability to nurse their young with milk from modified sweat glands called mammary glands. Mammals are warm-blooded, or endothermic. Bats, the only flying mammal, are numerous throughout the park, as are bobcats, cougar, fox, coyote and javelina.

Bobcats of Phoenix

Bobcats are common throughout Arizona at all elevations, especially in rimrock and chaparral areas, and in the outskirts of urban areas where food is readily available. Bobcats are generally seen alone, but groups may consist of mating pairs, siblings, or mothers with kittens. Bobcats are most active around sunset and sunrise, and it is not uncommon to find one napping under a shrub in a brushy backyard. Individual bobcats will defend a territory of one to 12 square miles.

Also known as wildcats, bobcats are much smaller than mountain lions and easily distinguished by their short tails. Despite their relatively small size, reports have cited bobcats preying on animals as large as adult deer.

Total length: 28-49 inches (71-125 cm)

Weight: 15-29 pounds (7-13 kg)

Diet: Small rodents, rabbits, squirrels, birds and carrion

Javelina or Collared Peccary of Phoenix

Javelina, or collared peccaries, have a limited distribution in the U.S. but are common in the Tonto National Forest and surrounding Phoenix area. They live in groups of 4 - 20 individuals led by an aged, experienced female. Javelina have scent glands on their lower backs. Within a herd, javelina often rub against one another, giving each herd a distinctive smell (at least to other javelina). Though similar in appearance, they are not pigs and differ from pigs in both behavior and physiology.

Total length: 35-40 in. (87- 102 cm)

Weight: 40- 65 pounds(18-30 kg)

Diet: Roots, tubers, seeds, mesquite beans, cactus fruit, agave, prickly pear pads, occasional carrion

Mountain Lions of Phoenix

The mountain lion or cougar, is the most powerful predator in Tonto National Forest and its surrounding area. They have the ability to kill prey much larger than themselves and can leap 20 feet in a single bound. Their jaws are so strong that they can bite through the shells of adult desert tortoises, something no other predator in the Sonoran Desert can do.

Total length: Up to 6 feet (1.5 m)

Weight: 75- 145 pounds (34 to 66 kg)

Diet: Mule deer, white-tailed deer, javelina, jackrabbits, squirrels

Phoenix - Scottsdale - Mesa - Ecology


The Sonoran Desert covers 100,380 square miles in the southwestern US and northwestern Mexico. Its boundaries are defined in part by the Mojave Desert (west), Chihuahan Desert (east) and Mogollon Rim (north).

The Sonoran sees low-intensity winter rains and violent summer 'monsoon' storm patterns; these two distinct rainy seasons are the driving force behind the greatest biological diversity of any North American desert.

The Sonoran Desert is home to at least 2,000 plant, 60 mammal, 350 bird, 20 amphibian and 100 reptile species. Of note, representatives of all three photosynthetic pathways (C3, C4, CAM) are found in the Sonoran.

The Superstition Wilderness is located east of Phoenix in the Tonto National Forest. It ranges from 2,000 - 6,265' across Desert Scrub, Semi-desert Grassland, Chaparral and Pinyon-Juniper woodlands.

The balance of trails pass through Desert Scrub and Chaparral, arid biotic communities dominated by succulents and specially adapted trees and shrubs.

SUCCULENTS

All cacti are succulents. Succulents store water in fleshy leaves, stems or roots in ways that maximize use and minimize loss. The soft, fleshy tissues of the cortex and pith can expand to accommodate additional volume for storing food and water.

This trait is most visible in the ribs and accordion-like outer flesh of a saguaro, which can expand to hold large volumes of water.

Though succulents can absorb large amounts of water in short periods, they can only absorb water from soil wetter than their own interiors (a limitation of passive diffusion).

Since desert rains rarely saturate the soil (or stay moist for very long), most succulents have shallow roots that radiate out from the plant to maximize surface level moisture. A saguaro's roots may extend out as far as the plant is tall, but not penetrate more than a few inches deep.

The stems and leaves of most succulents have waxy cuticles that seal the plant from water loss when the stomates are closed. Water loss is also mitigated by having few or no leaves leaves, and spines that deter consumption and molestation.

Water retention is aided by mucilages (polarized substances that cling tightly to naturally polarized water molecules), and inulins (a starch occurring in the rhizome, which upon hydrolysis yields fructose).

Many succulents practice a water-efficient variation of photosynthesis called Crassulacean Acid Metabolism (CAM).

CAM plants open their stomates for gas exchange at night and store carbon dioxide in the form of an organic acid. During the day stomates are closed, and combined with a waxy cuticle, seal the plant from water loss. Photosynthesis is then conducted with stored carbon dioxide at an optimal time.

Plants using CAM lose up to 90% less water than those using standard C3 photosynthesis. The tradeoff for employing CAM is a slower growth rate, since photosynthetic surface area is reduced. CAM plants are able to idle their metabolism by closing their stomates 24-7, recycling vital material and limiting respiration to moist tissue within.

Many non-succulent desert plants are able to shed leaves during drought and idle their metabolisms as well. The roots of desert shrubs and trees are extensive, and can radiate 2-3x the breadth of the canopy.

Substantial rain is required to wet the deeper roots of desert shrubs and trees. Though non-succulents take longer to respond to soakings than succulents, deeper soil stays wetter and available for absorption longer.

CHOLLA

Cholla are members of the Opuntia genus, distinguished by cylindrical stems made of segmented joints. These stems are actually modified branches that serve several functions -- water storage, photosynthesis and flower production.

Stems and joints vary in width, length, shape and color, as well as in the number of spines and glochids. Cholla spines are covered in a papery sheath that reflects sunlight and minimizes overheating.

Cholla thrive in coarse, well-drained soils. Some have adapted to mountain forests, while others require steep, rocky slopes in mountain foothills. Familiar species include Teddy Bear, Buckthorn, Silver, Pencil, Christmas, Chain Fruit and Staghorn

MESQUITE

Mesquite belongs to the legume family, ranging in size from a small shrub to 30' tall, depending on species and local conditions.

Mesquite branches have thorns to discourage browsing, and will shed leaves in the winter, and in periods of severe drought. They bloom in late spring - early summer, producing edible bean pods that contain durable seeds that must be scarified before they can germinate.

Mesquite are distinguished by wide-spreading lateral roots and deep tap roots considered the most extensive of any Sonoran desert plant. Most significantly, mesquite roots host nitrogen-fixing bacterial colonies that enrich local soil beds and facilitate growth.

PALO VERDE

Palo Verde means 'green stick' in Spanish. Two species of palo verde are found in the Sonoran Desert: Blue Palo Verde and Foothills Palo Verde.

Blue palo verde occur primarily in washes with finer soils, and require more water than the Foothills species. They grow comparatively fast but seldom live past 100 years.

Foothills palo verde thrive in the uplands where soil is more course and quickly drained. Foothills palo verde can live 100 - several hundred years.

Both species have deep root systems and are drought deciduous, sheading their leaves (and sometimes entire limbs) in times of extended drought. With or without leaves, palo verde rely mainly on their green stems and branches to conduct photosynthesis.

Palo verde is a common nurse plant for saguaro, with its modest canopy providing warmth and shade for the developing cactus.

Phoenix - Scottsdale - Mesa - Contact


Tonto National Forest Supervisor's Office
2324 E. McDowell Rd.
Phoenix, Arizona 85006
(602) 225-5200

Phoenix Interagency Fire Center
6335 S. Downwind Circle
Suite 101
Mesa, AZ 85212
(480) 457-1551

Cave Creek Ranger District
40202 N. Cave Creek Rd.
Scottsdale, AZ 85262
(480) 595-3300

Globe Ranger District
7680 S. Six Shooter Canyon Rd.
Globe, Arizona 85501
(928) 402-6200

Mesa Ranger District
5140 E. Ingram St.
Mesa, Arizona 85205
(480) 610-3300

Payson Ranger District
1009 E. Hwy 260
Payson, Arizona 85541
(928) 474-7900

Pleasant Valley Ranger District
P.O. Box 450, FR 63
Young, Arizona 85554
(928) 462-4300

Tonto Basin Ranger District
28079 N. Az Hwy 188
Roosevelt, Arizona 85545
(928) 467-3200