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All posts tagged geology

Knowing that lots of people would like to learn how geysers work, I’ll take a stab at explaining the requirements and the mechanism as simply as possible.

What is required to create a geyser and what’s happening when it erupts? All geysers have four requirements: water, heat, the right kind of rock, and a system of conduits and reservoirs (plumbing) that includes one or more constrictions to keep water and steam from flowing freely to the surface. The water pooled above such constrictions acts like a lid to maintain pressure on water below. Such constrictions differentiate geysers from the much more common hot springs. Although no one has yet been able to see exactly what this plumbing looks like, it must be something like this diagramGeyser Mechanism Figure drawn by my husband Bruno Giletti for Yellowstone Treasures. The countless different shapes the underground plumbing may take must account for the great variety in the patterns and timing of Yellowstone’s geyser eruptions—what I call their personalities.

Whether the water comes from the vent in the distinctive cone of Beehive Geyser2004_BeehiveG. or from the beautiful geyserite-ringed pool of Great Fountain Geyser, 2008_GreatFtnG the mechanism is the same.

Deep below the geyser’s vent or pool seen at the surface is a kind of rock that is rich in silica. In Yellowstone this rock, called rhyolite, was deposited in huge amounts when the caldera erupted. Silica is the primary element in the hydrous silicon dioxide (technical name for geyserite) that is deposited both along the conduits of the geyser’s water passages and all around its surface vent.

Also deep below a geyser are (1) a source of heat—in Yellowstone it is the still extremely hot volcanic rocks more than two miles below the surface—and (2) the water that has seeped into the earth from snowmelt and rain (meteoric water), and voila!—the geyser erupts.

As water gradually fills the reservoirs and is heated from below, it becomes superheated and forms steam bubbles, and the water pressure increases. Eventually, the steam pushes some water out of the vent, and steam—which requires something like a thousand times more space than water—is also released. When the pressure is thus sufficiently reduced, the steam in the conduit can blow the water column out of the vent. In many geysers, when the water supply is exhausted, the remaining steam continues for the steam phase of the eruption.

I have gleaned some ideas for this post from the sidebar my husband Bruno Giletti, a geochemist, wrote in Yellowstone Treasures (pages 88 and 89) and from T. Scott Bryan, a former ranger and also a geologist and author of books about geysers, including his Geysers: What They Are and How They Work. But as early as the mid 19th century, German scientist Eberhard von Bunsen and others already had it pretty well figured out. You can find out more about the study of the geyser mechanisms here in my September 2013 post.

Time lines

Categories: History, Janet Chapple's Other Writing, On the Web
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Jack Baronett wooden bridge

“Yellowstone Jack” Baronett’s bridge over the Yellowstone River


Inside the guidebook Janet shares many anecdotes about the human history of the Yellowstone area, from prospector Jack Baronett who built a wooden toll bridge in 1871 to tourist Hazel Decker who camped in her car for 52 days to observe Steamboat Geyser. In the road logs she discusses the evidence of prehistoric peoples and the recent discoveries scientists have made at the bottom of Yellowstone Lake using a submersible robot. She compiled a time line of many of the important events in the Yellowstone area and the world in a chapter of Yellowstone Treasures called “Chronology: Yellowstone Since 1800,” which takes readers from the Lewis and Clark expedition up to the present day.

But when she and I were creating the first edition of the book in 2001 it became necessary to cut pages from the manuscript and restrict the time line to the most recent couple of hundred years of human history, even though the geological history of the region goes way back before that. Her Geological Time Line, which you can read right here on this website, extends all the way from Earth’s formation 4.6 billion years ago, through the time the Absaroka Range volcanoes formed 53 to 44 million years ago, to the time 12,000 years ago when glaciers last covered Yellowstone. This last episode was the Pinedale Glaciation, evident throughout the lower Lamar Canyon.

Thanks for spending the time with us,
Editor Beth

Credit: Photo courtesy of the U.S. Department of the Interior, National Park Service, Yellowstone National Park.

Muskrat in a kettle pond

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Can’t resist sharing this cute picture of a muskrat in a Yellowstone kettle pond with you. What’s a kettle pond, you may ask? Here’s what the Yellowstone Treasures glossary has to say: “A pond formed in a depression caused by the ground collapsing when a buried block of glacial ice melted. Also called kettle hole.” The melting snow of the caption to this National Park Service photo is just this past winter’s. The hole is much older.

You can find out more about how glaciers reshape the landscape on the illustrated pages 311-312 of the “Geological History” chapter in the guidebook.

—Editor Beth

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Living in the Anthropocene
Part II

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Part II

What is the rationale for creating a whole new epoch called the Anthropocene? Is there any reason to think Earth has changed or is changing so much or so fast that we are in a span of time different from the Holocene?

terms for geological time divisionsThe geological time scale was first developed in the 19th century to divide up geological time. This time scale continues evolving as new methods of determining the dates of the rock strata allow for more and more precision. The broadest division of geological time is the era—the Archean is the oldest, and the Cenozoic the youngest. Eras are divided into periods: the Cenozoic is divided into the Paleogene, Neogene, and Quaternary. The Quaternary is currently divided into two epochs: the Pleistocene (pleistos is Greek for “most”) and the Holocene (holo- is for “whole, complete”). The smallest category is the age: the Pleistocene epoch includes four ages—the Holocene, being relatively short, has not been divided into ages. The latest stratigraphic chart (updated in January 2013) [1] places the beginning of the Holocene at 11,700 years ago; that date reflects the end of the last major glacial epoch. Considering that Earth has now been found to be 4.57 billion years old, the Holocene seems a mere blink of an eye.

What has led scientists to consider declaring a new epoch? Why should this be done soon and not a few centuries or millennia from now? After studying the subject, I will try to answer my first question, but I am not sure anyone can answer the second, unless the answer is that humans may not be around long enough to care about such things.

The first half of the 19th century was an important time for people who cared about Earth and how it may have been changing before they were born. Georges Cuvier (1769–1832) helped start the discipline of paleontology, which establishes units of geological time by studying the differences in fossil remains. He also recognized as early as 1812 that some thing or things (presumably floods) had caused mass extinctions. Another Frenchman, Jean-Baptiste Lamarck (1744–1829) developed the theory of inheritance of acquired characteristics. Later, two English friends, geologist Charles Lyell (1797–1875) and Charles Darwin (1809–1882) had the strongest influence on scientific thought for some hundred years, both believing that changes occurred gradually and extermination of species had always been a slow process. Still, the fossil record clearly showed there were periods when flora and fauna of certain types had quite suddenly disappeared, and very different types of critters had appeared practically overnight.

By the latter part of the 20th century, stratigraphers and other geoscientists had proven that major and quite sudden mass extinctions had occurred five times between about 440 million years ago (mya) and 65 mya, and there were many less-drastic extinctions. Now geoscientists and anthropologists are pondering whether we are plunging headlong into a sixth extinction. If so, what is causing it? How fast is it happening? Is it inevitable or can we act to slow, halt, or reverse it? If we are in a new epoch, just when did it begin? These are some of the questions that must be answered.

Let’s look at evidence of how humans have “altered the course of Earth’s deep history,” as expressed by paleontologist Jan Zalasiewicz of the University of Leicester, U.K., and his colleagues [2]. Take human population: huge increases have occurred in a short span of time (about the last two hundred years); with the consumption of fossil fuels, megacities have grown larger and larger; world population may reach 9 billion by 2050. In a record trapped into Antarctic ice that is almost a million years long, we can trace the recent rapid acceleration of chemical and biological effects on Earth. The increase in worldwide temperatures is causing changes that are unprecedented in their extent, severity, and speed, such as the rise of sea levels, species migration and extinction, and ocean acidity.

To name two of the chemical effects lumped together by Zalasiewicz, there are the well-known effects of excessive carbon dioxide on the atmosphere and the fact that black carbon particles, falling out of the air continually and appearing even in Arctic ice, are now classified as a major human carcinogen, in addition to their effect on climate. These were mentioned by Sybil Seltzinger of the International Geosphere-Biosphere Programme (IGBP) when she spoke at AGU.

I had been pondering these subjects for some time, but a very accessible article related to such questions fell into my hands late last month and precipitated my writing this essay. I read the two articles titled “The Lost World,” by the excellent New Yorker staff writer Elizabeth Kolbert [3]. To Zalasiewicz’s list of effects on Earth traceable to human actions she adds another of his favorite subjects—rats. Rats “have followed humans to just about every corner of the globe, and it is his professional opinion that one day they will take over the earth.” Kolbert has expanded her 2009 article, “The Sixth Extinction,” into a book of the same name to be released next month.

My next post in this Anthropocene series will continue on from pointing out some ways humans have changed the Earth to whether we can counteract any of these effects and why we should care.

References

[1] The stratigraphic timescale: http://stratigraphy.org/index.php/ics-chart-timescale
[2] Zalasiewicz, J., Williams, M., Steffen, W., and Crutzen, P. “The New World of the Anthropocene,” in Environmental Science and Technology: www.pubs.acs.org/doi/full/10.1021/es903118j
[3] Kolbert, E. “The Lost World,” in two issues of the New Yorker, December 16 and 23/30, 2013.

Special alert!

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[Editorial update on December 10, 2020: If you missed this talk in 2014 and still want to watch it, it’s on the USGS lecture page (http://online.wr.usgs.gov/calendar/2014/jan14.html). Jake began with some amusing history but quickly got into the technical details about volcanism and the Yellowstone Caldera. Enjoy!]

Here’s our chance to listen to one of the foremost authorities on what’s under Yellowstone explain what is known about the volcano.

Jake Lowenstern, U.S. Geological Survey scientist-in-charge of the Yellowstone Volcano Observatory, will talk tomorrow evening, January 23rd, at 7 pm PST about the latest understanding of earthquakes, uplifting ground, and steam explosions in Yellowstone’s caldera.

He will also talk about the amazing geological history of Yellowstone National Park and how scientists are monitoring the area in order some day to be able to forecast eruptions.

Tune in to: online.wr.usgs.gov/calendar/live.html

Holiday sale to end soon

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The latest edition of the Yellowstone Treasures guidebook came out in August. Here’s a review of the previous edition:

“[A] magnificent catalogued resource to the full enjoyment of a huge national park and area known as Yellowstone. The author has extensive knowledge and experience in exploring the beauties of the area. . . . Altogether, Yellowstone Treasures fills an ongoing need for new generations of park explorers and appreciators. She has spent much of her life becoming better acquainted with the riches of the area and she is generously sharing her knowledge with this beautiful guidebook. It is not to be missed.”

—Nancy Lorraine, Midwest Book Review, May 2009
You can find more great comments on our Reviews and From Our Readers pages.

As we explained in our November 4 press release, the updated fourth edition boasts:

  • Color tabs to indicate the six sections of the park
  • A dozen new pictures
  • Fully revised maps that show recent road changes
  • Updated geological information to reflect current research on what’s under Yellowstone and how it works, along with new diagrams like the one excerpted below
  • A new glossary of geological and other scientific terms

Yellowstone Treasures fourth edition geological figure

Part of Figure 5. What’s under Yellowstone: Moving plates, mantle plumes, and the Yellowstone hot spot.

The comprehensive guidebook also comes as an e-book in EPUB, PDF, Nook, and Kindle formats.

To encourage sales during the time of the year when not so many people visit Yellowstone, we started a holiday sale in November. You can buy the guidebook for $19.96 plus shipping and handling, which is 20% off the list price. To get the 20% discount on the print book, be sure to type the promo code “Holidays” in the Voucher box of the shopping cart. But hurry, this coupon only lasts until midnight on January 20, 2014.

Best wishes,
Beth Chapple, Editor

Yellowstone magma “Supervolcano” news

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The magma system or reservoir under Yellowstone is 2.5 times larger than previously known

[Editorial update: On December 18, 2013, USGS research scientist Jake Lowenstern, Scientist-in-Charge of the Yellowstone Volcano Observatory, e-mailed us to provide a clarification of this research:
“They are not imaging the hotspot, which is a global feature that extends into the mantle. They are imaging the shallow magma system that lies in the upper 10 km of the crust and feeds the actual eruptions.”]

Recent articles including “supervolcano” in the headline in the blogosphere and in media such as the New York Post shout “We’re probably doomed” and tell us of “a volcano that could wipe out U.S.” That gets people’s attention! The whirl of media activity is all due to research presented at last week’s American Geophysical Union (AGU) annual meeting in San Francisco.

An interesting session and a poster presented by Drs. Robert Smith and Jamie Farrell have stirred up a lot of emotional response, as has a November earthquake swarm in the area. The more these things are discussed in the media, the less rational readers seem to become. Media loves sensation. Perhaps the scientists whose work inspired the sensationalism will soon issue something to calm people down. Meanwhile, I’ll do what I can with this post.

I attended Smith’s 15-minute session at AGU and read Farrell’s poster last week. I am not a scientist, but I know enough about Yellowstone and current research to say this: The size of the magma reservoir below Yellowstone tells us nothing about when it will explode. Just as a reminder, magma is liquid or molten rock, including any dissolved gases or crystals, found deep within Earth.

More and more researchers are using various methods and instruments (seismometers, strainmeters, geochemical analyses, geodesy, instruments measuring electrical conductivity, and so on) to study what is under Yellowstone and its surroundings. Let’s wish them well and not panic about a catastrophe that is very unlikely to happen within the lifetime of anyone who can read this.

What about those earthquakes? One useful conclusion reached by this recent research is: “A large earthquake at Yellowstone is much more likely than a volcano eruption,” according to Farrell.

ON THE WEB: Here is some reliable and interesting information:
1. University of Utah’s Seismology and Active Tectonics Research Group’s faculty member Bob Smith stated on December 5th that U. of Utah’s seismographs will “continue to monitor Yellowstone earthquakes and will provide additional information if the earthquake swarm activity increases.”

2. U.S. Geological Survey’s Yellowstone Volcano Observatory. Swarms of (usually small) earthquakes have been reported frequently over the years; they are detected by the USGS seismograph array in Yellowstone.

3. Phys.org’s article called “Study: Yellowstone magma much bigger than thought (Update).” A relevant quote serves to sum up my comments here: “For years, observers tracking earthquake swarms under Yellowstone have warned the caldera is overdue to erupt. Farrell dismissed that notion, saying there isn’t enough data to estimate the timing of the next eruption. ‘We do believe there will be another eruption, we just don’t know when,’ he said.”

ON THIS WEBSITE: For more about the quest to understand what’s under Yellowstone, be sure to read the nuggets called “The Yellowstone Supervolcano,” “The Yellowstone Hot Spot: History of the Science“, and “The Yellowstone Hot Spot: Modern Science“.

Dynamic Earth: Yellowstone geology doesn’t stay the same

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Yellowstone Treasures‘s geology writing strives to keep up—

If you were to contemplate nature’s many facets and how quickly things change over the seasons and the years, you might think that you can at least count on the rocks and the mountains to stay the same. Wrong! Geoscientists will tell you that even mountains have their own dynamics. But their rate of change is much slower than humans can easily grasp in their relatively short lifetimes. Nature shapes the land we live on over centuries and millennia, but the rate at which geoscientists learn about it using new methods, ideas, and equipment is constantly accelerating.

Wanting to keep track of all this activity as it pertains to Yellowstone Park for the updated fourth edition of my guidebook, I was delighted when my old friend Dr. Jo-Ann Sherwin offered to bring us up to date about Yellowstone’s geology. I’ve known Jo-Ann ever since she was an outstanding student, whose advisor during her Brown University PhD research was my first husband Bill Chapple. She was the first woman to earn a PhD in their geology department and has gone on to a long career in research and teaching. She also lives in Idaho Falls, convenient to the west side of Yellowstone.

Jo-Ann reviewed the entire book and made numerous suggestions. She also rewrote large portions of our geological history essay, “The Stories in Yellowstone’s Rocks.” Our goal is to make our explanations accurate but concise and as clear as possible without any technical writing. Here’s a short sample from our essay that draws upon recent research into the source and age of the water for the park’s thousands of geysers and hot springs (hydrothermal features):

What makes the different hydrothermal features do what they do? Basically, the great volume of groundwater is heated by very hot rocks quite near the surface at Yellowstone.
There is a very large amount of old groundwater, at least 60 but perhaps greater than 10,000 years old, just above the magma below Yellowstone. The source of this water may have been the glaciers that covered the area or rain and snow in the surrounding mountains, 12 to 45 miles (20 to 70 km) distant. Present-day rain and snowmelt seep down and mix with this old water, become warmed to the boiling point, boil into steam, expand greatly, and find a way to escape upward. Most of the features occur where faults are common, making it easy for the heated groundwater and steam to return to the surface.

Understanding the science of Yellowstone

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My first mission in recent years has been to create a guidebook to Yellowstone that will stimulate others to visit and stay longer, helping them see, enjoy, and begin to understand all the amazing treasures the park has to offer. But exploring Yellowstone science is my second mission.

We can only become interested in subjects or activities after something or someone stimulates our curiosity. Think of your own elementary and middle school teachers or family members who have taken you out fishing or on long walks in the countryside, where they pointed things out to you. Several such teachers stimulated my curiosity and then encouraged me and helped me look further into aspects of the natural world. I remember particularly a teacher who was also a family friend. She introduced me to the variety of trees in our town by picking up leaves with me and teaching me their names and then pressing them. One year around the second week of August, she also taught me about the Perseid meteor shower, which fell so brilliantly in our clear Montana skies.

Many years later—concentrating often on the geology of Yellowstone—I’ve taken numerous summer courses offered by the Yellowstone Institute. I highly recommend those courses (http://issuu.com/yellowstoneya/docs/ya_summer_2013_catalog). I also audited a couple of Brown University geology classes, listened to and picked the brains of geologists, and most recently took in some sessions of the 2012 annual conference of the American Geophysical Union in San Francisco. 

Resources

A readily available source of recent Yellowstone scientific information is the journal Yellowstone Science, now available online (http://www.nps.gov/yell/planyourvisit/yellsciweb.htm).

Any of the above are good ways to begin to understand some of the basics of Yellowstone’s science. And the new fourth edition of Yellowstone Treasures is a good source too, because we have brought the scientific information as up to date with recent research as we can make it without technical language.

Three books I’d like to recommend that deal in different ways with Yellowstone geology are Roadside Geology of Yellowstone Country by William J. Fritz and Robert C. Thomas, Geology Underfoot in Yellowstone Country by Marc S. Hendrix, and Windows into the Earth by Robert B. Smith and Lee J. Siegel.

I’m planning to blog this fall about two other geological subjects: Why geology is not taught in our high schools nearly as often as are chemistry, physics, and biology, and the very big subject of what mankind is doing to our earth.

Yellowstone Treasures, Updated Fourth Edition

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I just got in trouble with TripAdvisor for mentioning something on their website [July 2013]. Sorry about that, but someone wanted to know how much difference there would be between the third and fourth editions of this guidebook, and I offered to send the person an autographed copy of the fourth edition from those copies I already have and told him or her another option would be to buy it from our website. My message must have lasted less than half an hour on there!

Here is what we have put out describing how the 2013 edition differs from the previous one: Covering everything there is to know about the world’s first and most diverse national park, the fourth edition of this bestselling guide to Yellowstone boasts more facts, anecdotes, history, and travel tips than ever before. Mile-by-mile road logs document every approach to the park and every interior road. Through easy-to-understand explanations and diagrams, readers will learn of Yellowstone’s campgrounds and facilities, geyser basins and the frequency of the geysers, out-of-the-way hikes, and flora and fauna.

Updates to this edition include tinted tabs to indicate the six different regions of the park and their approach roads, in addition to the tabs in previous editions for the geological, historical, and natural history sections; up-to-date scientific information to reflect recent research, including two new geological diagrams; highlighted historic items in the road logs; a dozen new pictures; and fully revised maps to show recent road changes and other details. A four-page glossary and a twenty-page index round out this indispensable addition to any travel library.

My offer stands to my blog post readers. For as long as my supply lasts, as author and publisher I can send you an autographed copy of Yellowstone Treasures for your use this summer, but I can only accept personal checks and money orders. You can reach me for details at: janet@yellowstonetreasures.com.