Geologic Field-Trip Guide to Volcanic and Hydrothermal Landscape of the Yellowstone Plateau

Description

Want something a little bit different than your usual "here's the best hikes to go on" guide to a national park? The US Geological Survey publishes "Field Trip Guides" to many of the western national parks. These are intended for professional geologists, to guide them to places of interest. But if you are a rockhound, have a teenager curious about science, or just like a deep dive into natural history, you might enjoy using this to give you a few tips of things to look for in Yellowstone. All the USGS publications are available as free downloads at pubs.er.usgs.gov, so I don't plan to copy a lot of them to MaM. From the web Yellowstone National Park, a nearly 9,000 km2 (~3,468 mi2) area, was preserved in 1872 as the world’s first national park for its unique, extraordinary, and magnificent natural features. Rimmed by a crescent of older mountainous terrain, Yellowstone National Park has at its core the Quaternary Yellowstone Plateau, an undulating landscape shaped by forces of late Cenozoic explosive and effusive volcanism, on-going tectonism, glaciation, and hydrothermal activity. The Yellowstone Caldera is the centerpiece of the Yellowstone Plateau. The Yellowstone Plateau lies at the most northeastern front of the 17-Ma Yellowstone hot spot track, one of the few places on Earth where time-transgressive processes on continental crust can be observed in the volcanic and tectonic (faulting and uplift) record at the rate and direction predicted by plate motion. Over six days, this field trip presents an intensive overview into volcanism, tectonism, and hydrothermal activity on the Yellowstone Plateau (fig. 1). Field stops are linked directly to conceptual models related to monitoring of the various volcanic, geochemical, hydrothermal, and tectonic aspects of the greater Yellowstone system. Recent interest in young and possible future volcanism at Yellowstone as well as new discoveries and synthesis of previous studies, (for example, tomographic, deformation, gas, aeromagnetic, bathymetric, and seismic surveys), provide a framework in which to discuss volcanic, hydrothermal, and seismic activity in this dynamic region. Preface Contributing Authors Abstract The Yellowstone Hot Spot and Snake River Plain Overview Volcanism Uplift Faulting The Yellowstone Magmatic and Hydrothermal System Geologic History Eruptive History of Yellowstone Plateau Volcanic Field (YPVF) First-Cycle Volcanism Second-Cycle Volcanism Third-Cycle Volcanism Precaldera Volcanism Cataclysmic Caldera-Forming Volcanism Postcaldera Volcanism (Plateau Rhyolite) Upper Basin Member Mallard Lake Member Central Plateau Member Extracaldera Volcanism Obsidian Creek Member Roaring Mountain Member Present-Day Magmatic System and Crustal Structure Glacial History Thermal Areas and Hydrothermal Activity Types of Geothermal Fluids Alkaline-Chloride Waters Acid-Sulfate Waters Calcium-Carbonate Waters Gas and Steam Connection Between Geography and Thermal Area Type Types of Thermal Features Fumaroles Mud Pots Hot Springs Geysers Hydrothermal Explosions Microorganisms Related to Thermal Features Geologic History of Yellowstone Lake Yellowstone Seismicity Notable Periods of Unrest: 1985‒2015 Yellowstone National Park and the Yellowstone Volcano Observatory Road Log Day 1: Meet at Bozeman in the Late Afternoon (Fig. 1.) Day 2: Bozeman to Old Faithful via West Yellowstone, Montana (Figs. 1, 28) Stop 1a. Hebgen Lake Fault Scarp Stop 1b. Earthquake Lake Visitor Center Stop 2. Norris Geyser Basin Stop 3. Tuff Cliff Stop 4. Firehole Canyon Stop 5. Midway Geyser Basin Day 3: Old Faithful to Pitchstone Plateau and West Thumb Geyser Basin with Return to Old Faithful (Fig. 36) Stop 6. Phantom Fumarole Trailhead and Pitchstone Plateau Flow Stop 7. Grant Strainmeter/GPS Site Stop 8. West Thumb Overlook Trail Stop 9. West Thumb Geyser Basin Stop 10. Upper Geyser Basin, Including Old Faithful and Geyser Hill Old Faithful Geyser Hill Day 4: Old Faithful to Mary Bay and Elephant Back Mountain, with Return to Lake Village (Fig. 41) Stop 11. Indian Pond, Storm Point, and Mary Bay Indian Pond Storm Point Mary Bay Stop 12. Elephant Back Mountain Day 5: Lake Village to Mud Volcano, Grand Canyon of the Yellowstone, Crater Hills, and Return to Lake Village (Fig. 41) Stop 13. Mud Volcano (Fig. 41) Stop 14. Grand Canyon of the Yellowstone Stop 15. Crater Hills Day 6: Lake Village to Caldera Overlook on Flanks of Mount Washburn, Calcite Springs Overlook, Lava Creek Tuff at Lost Creek, and Mammoth Hot Springs Terraces Finishing at Chico Hot Springs (Fig. 48) Stop 16. Caldera Overlook at Mount Washburn (Figs. 48, 49) Stop 17. Calcite Springs Overlook Stop 18. Lava Creek Tuff at Lost Creek Stop 19. Mammoth Hot Springs References Cited What You Need for the Field Trip