Geological Setting of Yellowstone National Park (click for larger version)

Did you know that geologist Jo-Ann Sherwin and I spent a lot of time updating the geology in the latest edition of Yellowstone Treasures? This map we revised is the most technical one, not intended for navigation like most of the 38 maps in the guidebook! Besides the types of rock in the different mountains, the map shows calderas. (A caldera is a large circular or elliptical crater or depression formed by the collapse of a large land area after the emptying of a magma chamber in a massive volcanic explosion.) Notice how the most recent—and famous—Yellowstone Caldera is marked with a solid line because much of its edge is visible at the surface. Meanwhile, the Henrys Fork and Huckleberry Ridge Calderas have a dashed outline to show that the caldera edge is buried under more recent volcanics. East of the park, the dotted outlines of the Heart Mountain detachment and its remnants show their general size, shape, and location. These are large chunks of Paleozoic sedimentary rock that became detached from the underlying rock and slid to the southeast over the Bighorn Basin. There’s lots more to explain calderas and other geological formations in the guidebook’s Geological History chapter.

We welcome your feedback on either our books or this website. Contact us!
—Editor Beth Chapple

Map credit: Jo-Ann Sherwin adapted this map with permission from Mountain Press’s Roadside Geology of Wyoming, 2nd ed., 1991, by David R. Lageson and Darwin R. Spearing.

Elsewhere on this website you can read about “The Yellowstone Caldera” and the Heart Mountain Interpretive center: https://www.yellowstonetreasures.com/2013/07/14/trip-report-heart-mountain/.

Sixth edition (May 15, 2020). ISBN: 9781733103206

Special features of the sixth edition:

• Cover photo by Janet Jones of SnowMoon Ink, Cody, Wyoming
• Extensive text and diagram updates by editor Beth Chapple and geologist Jo-Ann Sherwin
• Descriptions of the new overlooks on the South Rim of the Grand Canyon of the Yellowstone, the new trail to the Grand Prismatic Spring overlook, Steamboat Geyser’s resurgence in March 2018, and the surprise eruption of Ear Spring in September 2018
• Map updates and one new map by Jennifer Johnston of Inspirit Cartographics.

Fifth edition (2017, reprinted 2018). ISBN: 9780985818272

Special to the fifth edition:

• Cover designed by Vicky Vaughn Shea of Ponderosa Pine Design with a photo by Stephen Michael Gryc, composer and geyser gazer, chosen as part of our summer 2016 photo contest
• Won Silver in Independent Book Publishing Association’s Benjamin Franklin Awards in 2018
• 65 new photos, many resulting from our photo contest or from Suzanne and David Cane
• Revisions to the glossary of geological and other scientific terms by Jo-Ann Sherwin

Fourth edition (2013, repr. 2015). ISBN: 9780970687388

Special to the fourth edition:

• Cover photo of Old Faithful Geyser by geologist and family friend Don Forsyth, continuing the theme inspired by the old Haynes guides
• Text updates by author Janet Chapple
• A dozen new pictures
• 37 maps fully revised by mapmaker extraordinaire Linton Brown
• Thorough update of the geological information and a new glossary by geologist Jo-Ann Sherwin
• Book expanded to 400 pages
• Color tabs to indicate the six sections of the park

Third edition (2009, repr. 2011, 2012). ISBN: 9780970687333

• Cover focuses on Don Forsyth’s Old Faithful Geyser photo to evoke the covers of the old Haynes guides, published almost every year from 1890 to 1966
• Won Silver in IBPA’s Benjamin Franklin Awards in 2010. One judge wrote: “The third edition is a charm. I can’t think of any way to improve this book; it is well-researched, easily accessible and shows great love of place.”

Second edition (2005, repr. 2007, 2008). ISBN: 0970687311

Special to the second edition:

• Cover features the photo of Old Faithful Geyser by geologist and family friend Don Forsyth, along with insets of black bear cubs and Tower Falls
• Author Janet Chapple updated campground information and geyser activity
• Expanded section on wolves
• Book expanded to 392 pages
• Colors for each road log section added to the tops of pages to aid in navigation

First edition (2002). ISBN: 0970687303

Special features of the first edition:

• Cover designed by Elizabeth Watson with photos of Old Faithful Geyser, fireweed, sandbar and lagoon near Yellowstone Lake, mule deer. Lower Falls of the Yellowstone River, bison, and Mammoth Hot Springs
• Won Gold in Foreword Reviews’ Book of the Year Awards, 2002
• Author Janet Chapple wrote the 384-page book, from recommendations on the best sights and organizing the six road logs to the chapters on natural and human history
• Geologist and husband Dr. Bruno Giletti wrote the geology chapter and took most of the original photographs during their many years of trips to the Park
• Family friend Linton Brown creates 37 maps
• Informational sidebars are tinted according to their topic: geology and geography, human history, natural history, and park information

See our new E-book page to buy! You can get the new book in Kindle, ePub, or PDF formats for a variety of e-readers. If you’d rather borrow the book, you can ask your library to acquire this new version. (The ePub ISBN is 9781733103213.)

The print book will ship on May 15, but you can preorder it now, such as via Bookshop, a new online bookstore with a mission to financially support independent bookstores and give back to the book community. Buy local, indie first! Or see other places to buy the print version.

This photo of a major eruption of Steamboat Geyser gives a sense of its power but not its full height!

Here are a few of the geyser changes since the cutoff date for the first printing, February 2017. During 2017 Atomizer Geyser (p. 96) noticeably slowed its interval down from twice a day to an average of 20 hours. Page 93 of the first printing says Giant Geyser last erupted on September 28, 2015 (and that was after a five-and-a-half year hiatus, so it was pretty important). But nature has been busy proving the guidebook wrong. Giant erupted on July 7, October 9, and November 3, 2017, so we included the November date as the last eruption. Now the most recent eruption was actually July 24, 2018, and that was the third time in the month of July.

We are fortunate to have a website called GeyserTimes.org, where geyser gazers can log their observations or the notes from a ranger or scientist at the US Geological Survey (USGS) Yellowstone Volcano Observatory. Readings from seismometers, thermometers, and water discharge monitors are used to record eruptions even when nobody is there to witness them. That is how we know that Steamboat Geyser started erupting again on March 15, 2018, too late to get into the second printing. On page 233, it unfortunately still says “After eruptions in 2003 and 2005, Steamboat erupted once each in 2013 and 2014.” Yet as of today there have been 11 more since March 15, with the latest occurring on July 20, 2018! The USGS is keeping a running count of Steamboat’s water eruptions at the Yellowstone Volcano Observatory page.

You may have a chance to see the Giant or Steamboat Geysers on your trip to Yellowstone. Stay informed with Yellowstone Treasures, both the book and this website.

—Beth Chapple, editor and publisher

Photo credit: James St. John, June 4, 2018. Reproduced courtesy of a partial Creative Commons license. More photos and more about the history of Steamboat Geyser is available at on the geologist’s Flickr page for this photo.

Abiathar Peak

You can read the nugget “How did these mountains get striped?” to see the new explanation. Stay informed with Yellowstone Treasures, both the book and the website.

Photo by Niklas Dellby, 2013

Janet on the north shore of the lake, 2009

While we recline in the doldrums awaiting the opening of Yellowstone Park’s roads—mostly on April 21st, when the bulk of the plowing should be done and wheeled vehicles can again reach the interior of the park—I will pass along a link about a man who is building a robot to learn what is below Yellowstone Lake and is yet to be discovered and explained by scientists. Elsewhere I learned that project leader David Lovalvo’s crowd sourcing for this project reached its goal of raising $100,000 last year.

Granted, this article appeared on the Internet a year ago, but its interest is evergreen. Geoscientists at the U.S. Geological Survey, particularly Lisa Morgan, Wayne Shanks, and Kenneth Pierce, published classic research papers on what they had learned by 2007*. But there is much more of interest lurking in the depths of the lake, and I only hope to live long enough to find out more about it.

*See the section titled “Yellowstone Lake Studies” in: Integrated Geoscience Studies in the Greater Yellowstone Area: U.S.G.S. Professional Paper 1717.

I’ve been following research on the wonders of the lake for many years, especially as written up by Lisa Morgan of the U.S. Geological Survey and involving the Global Foundation for Ocean Exploration’s Dave Lovalvo.

A quick apology: My long silence as a blog-poster or tweeter has been due to spending all my time promoting my new historical anthology, Through Early Yellowstone, and working on rewrites needed for a super fifth edition of Yellowstone Treasures.

Part of Yellowstone Lake with Mount Sheridan

Just coming off the deadlines for suggesting changes to the designer’s files for my next book, Through Early Yellowstone, I want to pass on a delightful link from the Yellowstone Insider. On January 27th publisher Kevin Reichard passed on some interesting news published in Jackson Hole News and Guide. Hey! Sharing good stuff is what the Web is for, isn’t it?

My interest in microorganisms stems from a Yellowstone Institute class I took with researcher Anna-Louise Reysenbach way back in July 1999. Microbial research is a fascinating but very complex subject, and in recent years I’ve been learning and writing more about it. Take a look at my website “nuggets” from July 8 and 9, 2014, on “Yellowstone Park and the Quest for the Origins of Life.”

In a nutshell, some major research bodies, such as the USGS, NOAA, and several universities, are collaborating with the Global Foundation for Ocean Exploration to build a research boat and diving robot that will explore the bottom of Yellowstone Lake.

If all goes as planned, starting next summer the robot will take pictures and return samples of what it finds there. This will follow up on lake bottom research reported by USGS scientist Lisa Morgan and colleagues as part of a series of articles published in 2007: “Integrated Geoscience Studies in the Greater Yellowstone Area,” USGS Professional Paper 1717.

[Revised Feb. 27, 2017—Ed.:] The Global Foundation for Ocean Exploration created a fascinating ten-minute video starring microbial ecologist Dr. Reysenbach that does not seem to be available any longer. Although the video does not show us any microbes (seen only under a microscope), it does show some views of the thermal vents on the ocean bottom, teaming with hitherto unknown life.

Photo credit: This photo from page 144 of Yellowstone Treasures, fourth edition (2013), was taken by Bruno Giletti.

Lowenstern is Scientist-in-Charge of the Yellowstone Volcano Observatory and studies magma and volcanic phenomena in Yellowstone and all over the world for the United States Geological Survey, Menlo Park, CA.

The misconceptions this article lists are:

• When Yellowstone erupts it will be Armageddon
• The Yellowstone magma chamber is growing
• Yellowstone is overdue for a supereruption
• Yellowstone is rapidly rising
• Earthquake data indicates moving magma.

All this is well worth absorbing and passing on to any worrywarts you know! And if you want to read more of the “true facts” (what are false facts?) about supervolcanoes, the Volcano Observatory has recently updated another great page by the world’s best authorities on the subject.

At least the article about this that I just found ends with a sensible paragraph:

“Fortunately, the USGS agrees the likelihood of a Yellowstone volcano eruption is unlikely at this time. The volcano alert level is currently green, and seismographs detected only 178 earthquakes in the region, with the largest registering at a magnitude 1.9 on January 20, 2015. The USGS also calculates the odds against a Yellowstone eruption as 730,000 to one on an annual basis. As a comparison, the odds of a royal flush in poker is 1 in 649,740, so perhaps that’s not too comforting.”

For the best current information on the subject see this USGS page, or take a look at our own nugget about it.