Geologic Excursions in Southwestern North America
This volume, prepared as part of the Geological Society of America Annual Meeting in Phoenix, includes field guides covering aspects of the spectacular geology of southwestern North America. Field guides tackle the geology of the southern Colorado Plateau, from paleoenvironments of Petrified Forest National Park, to Jurassic sand dunes of southern Utah, to the San Francisco Volcanic Field, to awesome Grand Canyon. Appropriately for the 50th anniversary of the first lunar landing, one trip visits sites in northern Arizona that helped prepare astronauts for their missions. Several guides address aspects of the Proterozoic to Cenozoic tectonic development of the Transition Zone between the Colorado Plateau and the Basin and Range. Exploring the Basin and Range, guides feature Laramide tectonism and ore deposit development, features associated with large-magnitude Cenozoic extensional tectonism, large Miocene volcanic centers in northwestern Arizona, and tectonism and development of the lower Colorado River. Three field guides explore various aspects of northwestern Mexico, including tectonics and ore deposits of Sonora, fauna and paleoenvironments of Colorado River delta deposits, and volcanism in central Baja California. Finally, a guide analyzes anthropogenic earth fissures that have developed in the Phoenix metropolitan area.
Journey to the Grand Canyon: A geologic and hydrologic excursion across Arizona’s magnificent heartland
Published:September 04, 2019
Wayne Ranney, Marvin Glotfelty, 2019. "Journey to the Grand Canyon: A geologic and hydrologic excursion across Arizona’s magnificent heartland", Geologic Excursions in Southwestern North America, Philip A. Pearthree
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The Grand Canyon is perhaps our planet’s most widely recognized and single most important geologic landform. The goals for this trip are to give participants an understanding of the canyon’s formation and its dynamic hydrologic system. While our destination is clear, the journey will also provide opportunities to discuss Arizona’s larger geologic setting within the Basin and Range, Transition Zone, and Colorado Plateau physiographic provinces. Stops and discussions will include: (1) geologic setting and groundwater environment of the Phoenix basin; (2) Cenozoic landscape development of the Transition Zone; (3) Montezuma Well, a unique arid-land spring contained within a travertine mound; (4) ascent of the Mogollon Rim, the state’s second largest landform and entryway to the Colorado Plateau; (5) the San Francisco Volcanic Field and surrounding volcanic features, including Sunset Crater, a late Holocene scoria cone; and (6) multiple stops in Grand Canyon National Park to discuss its varied geology. The principal focus here will be on evolving concepts of the canyon’s formation since the time of John Wesley Powell, including the flurry of research results proffered in the past 20 years. Participants will walk the Trail of Time, Earth’s largest man-made geologic exhibit at over 2 km. Another equally important discussion will cover the modern hydrologic system of the canyon, which yields a tenuous supply of potable water from a single inner-canyon spring for over six million annual visitors and 2,500 full-time residents. The National Park Service has prioritized the replacement of the Trans-Canyon Waterline due to climate change concerns.