Geoscenario Resources—Yellowstone Hotspot: Geologist Task Now that you have explored as a team, the general story of the Yellowstone Hotspot, it is time for each of you to dive into more specialized information. The geologist focuses on the historic path of the Yellowstone Hotspot and how the major geothermal features work. Add helpful details to your notes for Geoscenario Team Questions. Then work together and combine all the information to successfully present your story of the Yellowstone Hotspot. Questions for the Geologist to Consider • How do the major geothermal features in Yellowstone work? • What is the historic path of the Yellowstone Hotspot? Information Water cools near the vent’s surface. Yellowstone National Park is known for its This cooler water “caps” the hotter diverse hydrothermal features. How do they water below. Eventually, superheated work? These diagrams explain how geysers build Side channels can often release pressure water flashes to steam, expanding and within thermal systems. Side channels lifting the water above the vent in an pressure to erupt and why hot springs are so blue. can act as indicators of when primary- eruption. The brilliant colors in hot springs come from feature eruptions may occur. archaebacteria. Aptly called extremophiles for Silica is dissolved from rhyolite (the their ability to survive in extreme environments, Side Channel volcanic rock) and precipitates as these colorful organisms can live in extremely sinter, which forms the geyser cone. high temperatures. Scientists study these bacteria Sinter Sinter to understand how their cells and proteins can Sinter is deposited on the walls and acts High-pressure area caused by survive and function in environmental conditions like a throttle in the vent by constricting expanding water and steam. far beyond the tolerance of most life. water circulation and allowing pressure to build up. Mud pots are drier than hot springs. Sulfuric acid disolves the surrounding sediments into the Recharge of superheated water. muddy pots. Fumaroles, or steam vents, are hot Courtesy of National Park Service springs with a lot of heat but so little water that the water boils away before reaching the surface. A hot spring shows colors caused by the presence of archaebacteria. © iStockphoto/ Wallentine Hot springs are the most numerous type of thermal feature in Yellowstone. Water temperature within some springs is as hot as 93°C (199°F). The intense blue color of some springs results when sunlight passes into deep, clear waters. Mud pot © iStockphoto/tupungato Courtesy of National Park Service Volcanic fumarole steam © iStockphoto/ ChuckSchugPhotography FOSS Next Generation Yellowstone National Park—Page 1 of 8 © The Regents of the University of California Version date November 20, 2018 Can be duplicated for classroom or workshop use. The Hawaiian Islands (with the youngest (Hawaii) closest) and the direction of the Pacific Plate. Formation of the Hawaiian Island chain. Courtesy US Geological Survey /Joel E. Robinson, Will R. Stettner Geologists not only study the current active 4.5 mya: Kilgore Tuff forms from eruption in features in Yellowstone, but they also ask questions Snake River Plain that expels 1,800 km3 of ash. about ancient active areas and the patterns in 1872: Yellowstone is designated as the first the landscape. Satellite images have allowed national park in the United States. geologists to view a pattern of ancient calderas through the Snake River Plain that become 1972: Jason Morgan uses caldera ages to progressively older southwest of Yellowstone. calculate the southwest motion of the North American plate, at 1-2 cm/year. The islands of Hawaii also offer a nice example of how a series of volcanoes can form when a plate 1994: Geologists at the University of Utah moves over a heat source. recalculate plate movements to current rates. Events Vocabulary 16-8 mya: North American Plate moves fumarole steam vent southwest by 6.1 centimeters (cm) per year. geyser hot spring with underground spaces that 12-10 mya: Bruneau-Jarbidge eruption in the trap steam pressure and create periodic eruptions Snake River Plain expells 250 cubic kilometers hot spring a naturally occurring warm body of (km) of ash, creating ash-fall fossil beds in the water Northeast, 1,600 km away. hydrothermal feature surface feature created 8 mya: North American Plate slows to move from underground superheated water southwest 3.3 cm/year. mud pot an acidic hot spring that dissolves rock 6.6 mya: Blacktail Tuff forms from eruption in to create a hot, muddy, bubbling spot 3 Snake River Plain that expels 1,500 km of ash. mya million years ago Track of the Yellowstone Hotspot Like the Hawaiian Hotspot and the Pacific Plate, the North American Plate has Courtesy US Geological Survey been moving over the Yellowstone Hotspot, melting a path through the Rocky Mountains. The red dots indicate earthquakes, and the yellow and orange circles show the ancient calderas. Courtesy US Geological Survey FOSS Next Generation Yellowstone National Park—Page 2 of 8 © The Regents of the University of California Version date November 20, 2018 Can be duplicated for classroom or workshop use. Geoscenario Resources—Yellowstone Hotspot: Seismologist Task Now that you have explored as a team the general story of the Yellowstone Hotspot, it is time for each of you to dive into more specialized information. The seismologist focuses on what a hotspot isand where major hotspots are found across the world. Add helpful details to your notes for Geoscenario Team Questions. Then work together and combine all the information to successfully present your story of the Yellowstone Hotspot. Questions for the Seismologist to Consider • What is a hotspot? • Where in the world are the major hotspots? Information In 1963, John Tuzo Wilson came up with a theory Plain, where the Yellowstone Hotspot triggered to explain volcanic activity in the middle of numerous caldera supereruptions before the continental plates or more-than-normal activity plume began feeding Yellowstone, about 2 million along faults. Wilson described stationary magma years ago. chambers, or hotspots, beneath the plate’s crust, which could cause volcanic activity far from any boundary zone. Since then, scientists have been able to create images of the Yellowstone Hotspot using seismic technology. Scientists at the University of Utah constructed an illustration of the Yellowstone Hotspot plume beneath Yellowstone National Park. Researchers believe that blobs of hot rock float off the top of the plume, then rise to recharge the magma chamber located 6–16 kilometers (km) beneath the surface. The illustration also shows a region of warm rock extending southwest from near the top of the Yellowstone underground plume. The park boundaries are outlined in green at the top plume. It represents the eastern Snake River of the illustration. The Yellowstone caldera, or giant volcanic crater, is outlined in red. State boundaries are shown in black. The park, caldera, and state boundaries are also projected on the bottom of the illustration to better show the plume’s tilt. 1 mile = 1.6 km. Courtesy US Geological Survey University of Utah This map shows some of the most established hotspots in the world. Courtesy US Geological Survey FOSS Next Generation Yellowstone National Park—Page 3 of 8 © The Regents of the University of California Version date November 20, 2018 Can be duplicated for classroom or workshop use. Other Major Hotspots the Cocos Plate. Unlike Iceland and the Mid- The Hawaiian Hotspot is one of the best-known Atlantic Ridge, four major reservoirs feed this and most studied hotspots. It was the basis for hotspot, causing changes in volcanic activity. Wilson’s understanding of how plates move over Thus, land formed on both sides of the divergent magma plumes. Ancient fishers first noticed that boundary over the past 20 million years. the islands got sequentially older as you moved toward the northwest. Notice the abrupt change in direction from the north-south Emperor Seamount chain to the southeastern progression of the chain of the Hawaiian Islands. Scientists continue to debate whether this change happened because of an abrupt change in plate movement or a shifting hotspot. © iStock photo/Liz Leyden The Azores Hotspot lies beneath the junction of three of the world’s largest tectonic plates (the North American Plate, the Eurasian Plate, and the African Plate), creating islands on all three plates. The Azores were uninhabited when Portuguese navigators arrived in the early 15th century. Because these young, remote islands were settled over two centuries, culture, dialect, and traditions vary from island to island. The main sources of income for all the islands are farming, fishing, and tourism. Courtesy US Geological Survey The island of Iceland was created by a hotspot beneath the Mid-Atlantic Ridge. The abundant geothermal reservoir, provided by the Iceland Hotspot, combined with hydropower from many rivers and waterfalls, supply all of Iceland’s electricity. This accounts for about 80 percent of the nation’s total energy. Iceland plans to be © iStock photo/Mlenny independent from oil by the year 2050. Events 1946: A model of the Hawaiian Islands by ages is created, based on dating of surface rocks. 1963: John Tuzo Wilson develops hotspot theory. Vocabulary caldera a cauldron-like feature formed when the center of a volcano collapses after a major eruption © iStockphoto/Rob Broek In the eastern Pacific Ocean near the equator, the hotspot volcanic regions that are fed by Galápagos Islands have geology as complicated superheated areas in the underlying mantle. and mysterious as their ecology. The Galápagos These can be found near or far from plate Hotspot rests beneath the Nazca Plate, and, like boundaries. Iceland, it is near a divergent boundary with mantle plume a thermal dome of hot rock that rises through Earth’s mantle and creates a hotspot FOSS Next Generation Yellowstone National Park—Page 4 of 8 © The Regents of the University of California Version date November 20, 2018 Can be duplicated for classroom or workshop use.