how were the mountains in arizona formed

Arizona's oldest rocks'1800 to 1400 million years of age'have not been adequately searched for remains of microscopic life. The mountain ranges here include the White Mountains to the east and the San Francisco Peaks to the northboth with average elevations of 11,000 feet, which Cobbles and gigantic boulders, as large as houses form sedimentary rocks in a matrix of volcanic material. Professor of Geography and Regional Development, University of Arizona, Tucson. Continents, oceans, the climate, our atmosphere, and all life have co-evolved on this planet in a complex, interwoven web. These days the San Andreas fault allows for the For the full report and geologic map and cross sections by R.K. Merrill and T.L. Subsequent erosion has generated large caves in the limestone, including Kartchner Cavern in Cochise County and the Grand Canyon's Vesey's Paradise. us: storm tracks funneled by Basin and Range topography, which ultimately You can unsubscribe at any time by clicking the link in the footer of our emails. throughout the region either dried up or initiated flow. 70 Million Years Ago. Volcanic activity, magmatism and mineralization shifted eastward into Arizona. We can see such a confinement for the Sonoran Desert on the map below, which resembles a shallow bathtub, breached at its south end where it receives Pacific moisture, and at its north end where it joins the rain-starved Mohave Desert. The tilting of those blocks is what accounts for the tilted layers in Papago Park and in the volcanic rocks around the ASU campus, Reynolds said. Late Cretaceous strata of the northern Santa Rita Mountains contain a remarkable fossil record including the titanic long-necked sauropods, horned and duckbill dinosaurs, and some of Arizona's oldest fossil mammals. Ground ruptures associated with prehistoric earthquakes are known from near the towns of Green Valley and Gila Bend in Arizona. About 10,000 to 12,000 years ago, Paleo-Indians settled in what is now Arizona. New York: Noonday Press, 1990. the past four million years. and rose along deep cracks. (See the chapter "Desert fracture-free, may weather into large, spectacular domes that develop The lava flows, volcaniclastic, and epicIastic rocks can be separated into two age groups: the first of Oligocene and Miocene age and the alluvial fan shapes are not obvious. Previously, Laurentia only extended as far southwest as present day Wyoming, but with Granitic plutons tended to form near well-developed crush zone and often have tungsten and quartz rich veins in garnet-muscovite granitoids and pegmatite dikes. cones and flows Since that time the chief geologic activity has been the movement of rock debris off mountains and into adjacent valleys through stream action, as seen in illustration D. Most Basin and Range valleys are filled with 5000 feet (1525 m) or more of gravel, sand, and clay beds, If a flat (horizontal) set of joints is also present, weathering along this base eventually forms a rounded balanced boulder. sub alpine spruce-fir forests, cool enough to have supported semi-permanent ice masses on shady north slopes during the Pleistocene (the past two million years). survival story, like so many others, continues to unfold as the Sonoran Desert evolves. Geologists say the mountains there likely were deposited by landslides along a steep mountain front that has since eroded away. transport of all land on its west side (the Baja California peninsula Migratory routes are often determined by geologic processes. Desert varnish Juniper Mountains Yavapai County. Since Gootee described it this way: Other continents have come and gone and hit him and been pulled away and, and hit him again, and been pulled away, and slid past them and buried them in, uplifted him and eroded them and buried them again.. South Mountain, the Estrellas, maybe, San Tans, White Tanks, Sacaton mountains all of these mountains, like in the McDowell Mountains as well those start to form as nascent mountains around 25 to 20 million years ago, he said. Over the course of millennia, rivers and their tributaries have carved distinctive landforms on these surfaces. the rising magma with water-saturated sediments, which adds the force The Sonoran Desert contains a characteristic series of landforms, shown in the illustration below. Gootee simply means that, in the days of the dinosaurs, the area was a mountain range, built by the same kinds of tectonic forces currently uplifting the Andes in South America. continues in our own time. Mountains around Phoenix formed by eons of pushing, pulling and hitting Nicholas Gerbis / KJZZ Dec. 21, 2018 A view from the Hole in the Rock at Papago Park in Phoenix. Geologists say the mountains there likely were deposited by landslides along a steep mountain front that has since eroded away. Corrections? produced rhyolites (light-colored Amid these fractures, some blocks of rock rose to become mountains while others dropped to form valleys. These unusual craters owe their explosive origin to an encounter of Sharp, Robert P. Geology Field Guide to Southern California. Freeman & Company, 1966. [6], The USGS published research in 1997, examining the Pennsylvanian and Permian age sandstone, limestone and siltstone underlying Flagstaff and the southern Colorado Plateau, which forms a complex regional aquifer with poorly understood groundwater flow. Formed miles deep within Earths crust before being exhumed, this ancient structure has guided surface weathering and erosion for millions of years. For the remaining 350million years of the Proterozoic, Arizona experienced extensive erosion, with only a few areas of sediment deposition in down-dropped basins. The subduction of the Farallon Plate beneath western North America remains a poorly understood event, although new seismic and computer tomography modeling is shedding light on the event. Eventually, the ash and basalt that solidified inside the collapsed caldera uplifted and eroded.

Specifically, the Pacific Plate and the North American Plate came into contact and created the major tectonic forces that uplifted, wrinkled, and stretched Arizonas geologic crust, forming its mountain ranges, basins, and high plateaus. Specifically, the Pacific Plate and the North American Plate came into contact and created the major tectonic forces that uplifted, wrinkled, and stretched Arizonas geologic crust, forming its mountain ranges, basins, and high plateaus. Twenty-five (million to) 15 million years ago, the continental crust was stretched, and the rocks in the South Mountains were pulled out from underneath that area to the northeast, underneath Fountain Hills, and brought up to the surface, said ASU geologist Steve Reynolds, an expert on bedrock features in metro Phoenix. Local governments take a risk in stabilizing channel embankments with soil cementation. There, ancient submarine hydrothermal vents precipitated sulfides directly onto an ancient seabed, creating massive copper and zinc ore sulfide deposits. Tucson residents reported large clouds composed However, slight readjustments to changing conditions do occur. This story is part of Elemental: Covering Sustainability, a new multimedia collaboration between Cronkite News, Arizona PBS, KJZZ, KPCC, Rocky Mountain PBS and PBS SoCal. What was here, we ask, when dinosaurs roamed, or when mountains were new? South Mountain arose from the hotter caramel layer 6 miles beneath the surface. Learn more about what we do and how to find our content on our broadcast, digital and social media platforms. Youd fall a mile and a half, said Steve Skotnicki, an independent researcher who uses drill cuttings from water wells across metro Phoenix to map the areas geological and hydrological prehistory. For the most part, water from these aquifers is high quality although some wells exceed EPA recommendations for arsenic, barium, uranium and lead. The Sonoran Desert and nearby mountain islands exhibit nearly two miles of vertical relief, from sea-level deserts to mountaintops at 9500 feet (2900 m) that harbor WebAn Elevated Perspective. Roadside Geology of Arizona. Company, 1990. Pleistocene fauna of the last 2 million years included camels, herds of bison and near-modern horses, mastodons, imperial mammoths, giant ground sloths, wolves, lions, giant beavers, and short-faced bears. pendulum clocks in Phoenix. nearly flat faults, such as the Catalina detachment fault shown in illustration Rebecca Noble | The Daily Wildcat . Dubuque, Iowa: Kendall/Hunt The border fence separating Arizona from Mexico as seen from the Nogales, Arizona side on Nov. 20, 2016. (Refer to the seismicity map.) These ranges formed along the eastern edge of a region of carbonate sedimentation some 17 miles (27 km) thick, which had accumulated from the late Precambrian to early Mesozoic time (i.e., between about 1 billion and 190 million years ago). in the Superstition, Tucson, and Ajo mountains. However, all of these civilizations Mesozoic fossil beds (150 to 90 mya) represent a regional trend toward terrestrial conditions as the land rose and drained.

WebYou need to be more specific as Arizona has dozens of mountain ranges. Volcanic material is interbedded with dune sandstones in the Santa Rita Mountains, to the south of Tucson and correlate with the Aztec Sandstone and Navaja Sandstone, spanning northern Arizona to Zion National Park. Rocks that ancient can pose particular problems for scientists trying to unravel their history, Gootee said. As climates and habitats change, plant and animal species either adapt, migrate to more favorable ground, or become extinct. sedimentary rocks of diverse age (from 30 million to 1200 years old), exposed over a wide area, but most famously in the walls of Arizona's Grand Canyon National Park. Laguna Mountains (Arizona) Yuma County (see also: Laguna Mountains (Calif)) Las Guijas Mountains Pima County. Although they are labeled mesas and plateaus, their ruggedness and inaccessibility have been exaggerated. https://www.britannica.com/place/Arizona-state, Official Tourism Site of Arizona, United States, CRW Flags - Flag of Arizona, United States, Arizona - Children's Encyclopedia (Ages 8-11), Arizona - Student Encyclopedia (Ages 11 and up), Tribe, US officials reach deal to save Colorado River water, Spoon spotted: Arizona Dairy Queen's big red spoon found, Towering Monument Valley buttes display sunset spectacle, Fox lawsuit highlights effects of conspiracies on Dominion, Arizona Dairy Queen on the hunt for missing red spoon statue. Tohono O'odham residents at the village of Pan Tak Granite intrusions 190million years ago enriched many veins with minerals and generated copper porphyry gold deposits. The maps, reports, and other information and content on this website are provided as a public service for informational purposes only. The limestone contains stromatolite remains, mounds of blue-green algae. Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. The Santa Rita Mountains and Tombstone Hills contain silver and lead formed by hydrothermal fluids in fractures, during the Laramide orogeny. The Mescal Limestone metamorphosed, forming asbestos and superheated diabase magma "baked" the limestone to marble. The Mesoproterozoic formations in the Grand Canyon are overlain by the 850million year old, Neoproterozoic Chuar Group and Sixtymile Formation sedimentary rocks. The Colorado River forms the boundary with California and Nevada. In the last 14million years of the Miocene, Pliocene, Pleistocene and the current Holocene, the subducting Farallon slab was cut off by strike-slip motion on the San Andreas Fault, coupled with a transform boundary. (See photo below.) The Mid-Tertiary ignimbrite flare-up created smaller mountain ranges with extensive ash and lava in the Cenozoic, followed by the sinking of the Farallon slab in the mantle throughout the past 14million years, which has created the Basin and Range Province. We often wonder what the land we stand on was like in times past. cemetery at Mission San Xavier del Bac near Tucson, and stopping large The lava flows, volcaniclastic, and epicIastic rocks can be separated into two age groups: the first of Oligocene and Miocene age and the All rights reserved. The volcanic caldera cycle that created the Tucson Mountains rock formations also gave rise to the Silver Bell Mountains, Sierrita Mountains, Santa Rita Mountains, Chiricahua Mountains, Superstition Mountains, Galiuro Mountains, Dos Cabezas Mountains and other southern Arizona ranges, he added. Learn more about Mailchimp's privacy practices here. Publishing Company, revised edition 1976. piedmont is used in situations where The Phoenix Mountains North Mountain down though just south of Piestewa Peak are 1.7-billion-year-old rocks that have endured eons of punishment. Users are responsible for verification of all facts and information to their own satisfaction. Groundwater serves to augment surface water. The intense All rights reserved. By clicking below to subscribe, you acknowledge that your information will be transferred to Mailchimp for processing. Balanced boulders can be seen along the Gates Pass road in the Tucson Mountains, along the Mt. Published Apr 5, 2023 5:09pm above), where tremendous heat from beneath was concentrated. The hump of Camelback Mountain is made mainly of granite, which forms via volcanic activity underground. Both aquifers have seen extensive pumping increases since 1975.[8]. Laramide copper porphyry deposits are common around Tucson and include the Twin Buttes, Sierrita-Esperanza, Rosemont, Silver Bell and Mission-Pima mines, as well as the historical Ajo mine to the west. About 10,000 to 12,000 years ago, Paleo-Indians settled in what is now Arizona. This last climate change marks the birth of the modern Sonoran Desert ecosystem. These calderas collapsed on themselves, leaving behind remnants such as the Cat Mountain Rhyolite, to the west of Tucson. Plate tectonicsthe shifting of large, relatively thin segments of Earths crustand stream erosion have done the most to create Arizonas spectacular topography. [5], Because of its arid climate and large population, water is critically important in the state of Arizona. Then as mountains slowly erode to In northern Arizona, the Mogollon Rim (the Rim) transitions from desert to forests of pine and alpine where bear and elk roam. 2023 Cronkite News. The lava flows, volcaniclastic, and epicIastic rocks can be separated into two age groups: the first of Oligocene and Miocene age and the

Near the end of major Basin and Range formation, about 6 million years ago, Geology of Arizona. is part of a regional trend throughout the West called "arroyo cutting," likely caused by a combination of factors, including increased cattle grazing However, rare heavy rains produce torrents of mud, rocks, and vegetation that cascade rapidly down steep narrow canyons in the mountains. Though we may imagine different landforms, different vegetation, we probably still imagine "here" as a definite, and permanent, spot on the globe, a place with constant longitude and latitude, a place whose changes we could trace through time, perhaps by reading the record in the strata beneath our feet. WebJohn the Baptist Mountains Pima County. (See photograph below.) The field contains a central 4000-foot tall 70 Million Years Ago. Get a Britannica Premium subscription and gain access to exclusive content. WebYou need to be more specific as Arizona has dozens of mountain ranges. Arizona is the sixth largest state in the country in terms of area. Although widely reputed for its hot low-elevation desert covered with cacti and creosote bushes, more than half of the state lies at an elevation of at least 4,000 feet (1,200 metres) above sea level, and it possesses the largest stand of evergreen ponderosa pine trees in the world. Groundwater was up to 7000 years old in the C aquifer and up to 22,000 years old in the Redwall-Muav, based on tritium and carbon-14 analysis. Before this geologic onslaught there is good evidence the region stood as an extensive upland, devoid of today's mountains and smoothly connected to all the surrounding highlands (see map above). As it domed upward, South Mountain sent fault blocks sliding down into the valley. Earlier forms included ancestral horses, giant rhino-like titanotheres, and oreodonts (ancestors to peccaries and camels). be toxic to other plants. Virtually all of Arizona lies within the Colorado River drainage system. from the flood plain of the San Pedro River, while other streams and springs The oldest Proterozoic metamorphic and igneous rocks were intruded with granites and pegmatite between 1.45 and 1.4billion years ago. The San Francisco Peaks, for example, were formed by volcanism, but other ranges were formed by other processes. Find out how your news organization can use Cronkite News content. a severe sideways ripping action began along the Pacific coastline; this The Great Unconformity is a famous gap in the stratigraphic record, as Arizona experienced 900million years of terrestrial conditions, except in isolated basins. The northeastern two-fifths of Arizona is part of the scenic Colorado Plateau. Missoula, Montana: Mountain Press Publishing A few thousand years ago, the Ancestral Puebloan, the Hohokam, the Mogollon and the Sinagua cultures inhabited the state. than what's on the surface-the often-neglected third dimension is vital, During the Pennsylvanian and the Permian, the final assembly of the Appalachian Mountains to the elevation of the Himalayas occurred with the Alleghanian orogeny and the formation of the supercontinent Pangaea. By about 8 million years ago, the pull-apart action stopped, the thinned crust cooled, and Basin and Range mountains and valleys stabilized. Learn more about Mailchimp's privacy practices here. Some comprise truly ancient rocks. During the Eocene, Oligocene and Miocene, the Mid-Tertiary igmibrite flare-up, a mountain building event tied to the Farallon Plate, erupted huge quantities of volcanic ash. Geologists say the mountains there likely were deposited by landslides along a steep mountain front that has since eroded away. The northward dragging action is related to that which originally ripped By Caitlyn Murphy. All these effects The region retreated to marine conditions and clam shells built a limestone deposit around Bisbee. This heating became important when the Pacific Coast became somehow attached or glued to the edge of the Pacific Ocean tectonic plate, which was at the time beginning to move northwest relative to the main continent. Arizona's oldest rocks overall are metamorphosed volcanic rocks, including basalt and rhyolite and related sedimentary rocks, that now constitute the bottom of the Grand Canyon and formed beginning 1.8billion years ago. Basin and Range country is unique'no other region of similar The breakup of Pangaea was accompanied by the subduction of the Farallon Plate, which drove volcanism during the Nevadan orogeny and the Sevier orogeny in the Mesozoic, which covered much of Arizona in volcanic debris and sediments. 2023 Cronkite News. The Black, White, and Verde rivers are the primary perennial tributaries of the Salt River, which enters the Gila River southwest of Phoenix.

The Martin Formation in southern Arizona contains limestone, sandstone, shale and chert deposited in the Late Devonian and laden with fish and invertebrate fossils. concentric rounded joints just like a layered onion, from which segments of layers separate, exposing a cone-shaped core. covered with a single layer of desert-varnished rocks. Arizona is a land of contradictions. In northern Arizona, the Mogollon Rim (the Rim) transitions from desert to forests of pine and alpine where bear and elk roam. To Arizonas two major physiographic divisions, the Colorado Plateau and the Basin and Range Province, geologists add the Transition Zone (or Central Highlands). Far less rugged than adjacent portions of the plateau in Utah, these tablelands in Arizona consist mainly of plains interrupted by steplike escarpments. WebThe history of Arizona encompasses the Paleo-Indian, Archaic, Post-Archaic, Spanish, Mexican, and American periods. The crack at the edge of the ripped-off land Its romantic reputation as a wild desert and a place of old-fashioned close-to-the-earth simplicity is at variance with the fact that after the 1860s the states economy became industrial and technological long before it was pastoral or agrarian. */. volcanoes then collapsed, forming large circular basins called calderas, as seen The region oscillated between terrestrial and shallow ocean conditions during the Paleozoic as multi-cellular life became common and three major orogenies to the east shed sediments before North America became part of the supercontinent Pangaea. It consists largely of broad, open-ended basins or valleys of gentle slope. natural history. Beginning about 25 to 30 million years ago, Arizona and the West experienced crustal stretching which began to tear things apart. Mountaintops range from 3000 feet (915 m) in the west to 10,000 feet (3050 m) in the east. lichen colonies; the wide variety of landforms and rock types. Contrary to desert stereotypes, sand dunes are nearly nonexistent, and stony desert surfaces are seldom visible except in the far southwestern portion of the state. But its head known, appropriately enough, as the Camel's Head Formation is composed of sedimentary rock, which forms from particles deposited on the floor of a body of water. Webhow were the mountains in arizona formed. As the mountain domed up, it shed the blocks that became Camelback Mountain and the Tempe Buttes. WebThough glaciers in Arizona mountains were confined to elevations above 9000 feet (2740 m), vigorous stream runoff during the first million years removed much soil and debris from mountain slopes and deposited it in many large fan-like deposits below the mouths of the larger canyons. Boulders are eventually shaken free by earthquakes or uneven weathering and litter the nearby ground. The Ray, Miami, Pinto Valley, Morenci, Safford, Carlota, Superior and Resolution mines are examples of open-pit extraction sites for copper in east-central Arizona. of steam blasts to the normal volcanic fountain. Dubuque, Iowa: Kendall/Hunt up further into an aligned series of "pimples," due to their heat and of valley bottoms rise from sea level near Yuma to 5000 feet (1525 m) in southeast Arizona, where deserts are replaced by grassland valleys. #mc_embed_signup{background:#fff; clear:left; font:14px Helvetica,Arial,sans-serif; } of the Gulf of California. However, unlike the Nevadan orogeny, there was no significant vein-related mineral formation in Arizona. Considerable high country exists west of the Sonoran Desert in Baja California's Sierra San Pedro Martir and in southern California's coastal Laguna Mountains, loosely joined to the imposing Sierra Nevada farther north through the Palm Springs Unlike in the past, the marine transgression originated to the southeast and the east of the Western Interior Seaway. The Kaibab Limestone is a famous formation from this time, covering much of northern Arizona. PHOENIX Ask Brian Gootee of the Arizona Geological Survey how the mountains ringing metro Phoenix formed and youll get what sounds like a riddle: When you think about this flat (Salt River) valley, I think you have to kind of start over with what it wasnt, right before it started to become what it would be, he said. The Sonoran Desert lies in a region of the West called the Basin and Range geologic province. For example, climate dictates that a river be perennial or intermittent, and that a lake expand or dry up. of the past are interwoven into a tapestry of cause and effect on a grand The oldest rocks in Arizona likely date to the late Archean or early Proterozoic, although evidence of earlier geology was overwritten during the Yavapai orogeny and the Mazatzal orogenymajor mountain building events 1.8 to 1.6billion years ago. Arizona is known as the Copper State because it produces two-thirds of US copper annually. The overlying tuff was deposited during an eruption which created a discussion of the causes of these phenomena as they have come to be understood Low angle normal and detachment faults deformed sedimentary and volcanic rocks from the final phase of the event. Intense heat rising into the crust was hot enough to entirely melt and soften portions of the lower continental crust into a viscous fluid, similar in consistency to molasses taken out Company, 1983. Published Apr 5, 2023 5:09pm the line of mountains (shown as metamorphic core complexes on the map, Following this activity, the stretching action quickly spread across most of the entire region, which would eventually become the modern Basin and Range country. 2:15 pm. Trilobite and brachiopod fossils appear in the stratigraphic record. The Oracle Granite, near Tucson, the Ruin Granite, close to the Ray-Superior area, and the Zoroaster Granite at the base of the Grand Canyon all contain one to two inch long, pink orthoclase crystals. fashion at the startling speed of a few inches per year. and parts of western California) toward the north in a very irregular The term bajada is generally reserved for those areas where obvious alluvial fans line the mountain front, while One of these, the Pinacate field, lies just (See illustration C.) Virtually all mountains of the region were simultaneously born in this way; this also explains the semi-parallel trend of the region's mountains and valleys'they are perpendicular to the direction of stretching. These minerals were emplaced by hot hydrothermal fluids moving through the weak zones in the rock. rising air cools, annual precipitation Pediments are buried shoulders of mountain rocks that extend from the edge of the exposed mountain some miles toward the valley center, where they contact the buried Basin and Range fault, beyond which lies thick valley alluvium (gravel, sand, silt, and clay). These volcanic areas occasionally The main mass of the Tucson Mountains is composed of rhyolite produced during an earlier rhyolite volcanic episode some 70 7,359,197. WebThe White Mountains in east-central Arizona were the site of middle to late Cenozoic volcanism. The vast Cactus Plain dune field near Parker derives its sand from the old shoreline sands of the Colorado River. Let us consider the topography WebYou need to be more specific as Arizona has dozens of mountain ranges. Only during the infrequentand occasionally devastatingflood periods does runoff water advance downstream past the numerous dams built on the Salts system. Spectacular conical granite domes with "onion-peel" structures may be seen along the high ridges on the west side of the Santa Catalina Mountains above Catalina State Park. A Native American tribe in Arizona has reached a deal with the U.S. government not to use some of its Colorado River water rights in return for $150 million and funding for a pipeline project, A giant red spoon that was stolen from an Arizona Dairy Queen and sparked a mystery on social media was found and its partly thanks to Pokmon GO, A sunset spectacle featuring towering rock formations that resemble mittens played out this week at Monument Valley on the Arizona-Utah border, Dominion Voting Systems has been ensnared in a web of conspiracy theories that have undermined public confidence in U.S. elections among conservative voters, The owners of a Dairy Queen in Phoenix remain perplexed and slightly amused as to why someone would steal the giant red spoon that adorned their restaurant, Tour the butte escarpments and vegetative landscape of Arizona desert terrain, Travel down the Colorado River, through the Colorado Plateau, to behold Arizona's Grand Canyon. Such spectacular landforms as the Grand Canyon and the Painted Desert have become international symbols of the regions ruggedness, yet Arizonas environment is so delicate that in many ways it is more threatened by pollution than are New York City and Los Angeles. By Caitlyn Murphy. Arizona, constituent state of the United States of America. As a result, steep normal faults formed the horst and graben landscape of the Basin and Range Province. WebJohn the Baptist Mountains Pima County. region. They write new content and verify and edit content received from contributors. We recommend moving this block and the preceding CSS link to the HEAD of your HTML file. The volcanic caldera cycle that created the Tucson Mountains rock formations also gave rise to the Silver Bell Mountains, Sierrita Mountains, Santa Rita Mountains, Chiricahua Mountains, Superstition Mountains, Galiuro Mountains, Dos Cabezas Mountains and other southern Arizona ranges, he added. calcium); basalt formed beneath the continent during pull-apart actions and alkalinity determine the kinds of plants that will survive on them. lifetimes or of centuries. Many small mountain ranges in western Arizona, including the Superstition, Galiuro, Chiricahua and Tumacacori mountains are predominantly made up of ash flow tuff from these eruptions. Before our eyeblink of human occupation, what we call the Valley of the Sun was at the bottom of shallow seas, built up multiple mountain ranges and fluctuated between wet, cool ice ages and, of course, a dry heat.. A few thousand years ago, the Ancestral Puebloan, the Hohokam, the Mogollon and the Sinagua cultures inhabited the state. It may be hard to imagine but it puts logic around how the mountains in Tucson were formed. walls in Tucson and El Paso, knocking over an adobe wall at the Spanish