Monday, October 19, 2020

Join Me On a Grand Canyon River Trip - Virtually - November 5, 2020

The Covid pandemic has really slowed things down in my world, as I know it has in all readers of Earthly-Musings. Faithful readers have certainly noticed a sharp drop-off in posts from me as I first, recovered from bilateral knee surgery in late 2019; then in March, the travel industry was put in complete shutdown by the worldwide pandemic. My river trip with the Museum of Northern Arizona in May, 2020 was the first cancellation to my schedule (however, it was run later on August 1 with great safety and success). Then, the same month my Smithsonian Journeys trip to Machu Picchu and the Galapagos Islands was canceled. Another Grand Canyon geology-themed river trip scheduled for late August was canceled next. I lost another two trips that were scheduled this month - a 10-day excursion with Smithsonian to Grand Canyon, Bryce and Zion; then, an Around the World By Private Jet adventure with TCS Travel (that is a tough one to miss). Patagonia and Easter Island with Yavapai College was scheduled for November and December this year but is now rescheduled for 2021 (fingers crossed). And lastly, my 30th trip to Antarctica, scheduled for January, 2021 with Smithsonian Journeys, will have to wait one more year. These are First World problems I know. People are suffering a lot more from this than losing work and our hearts go out to those who have lost loved ones. Stay safe!

Nevertheless, I have been busy with Zoom lectures for various non-profits including Smithsonian Journeys, Geofest/Earth Science Week, and others. I want to bring to your attention an upcoming lecture for a good cause! Museums have been especially hard hit by the lack of visitation due to the spread of the virus. For that reason, I will be holding a fundraiser for the Museum of Northern Arizona on Thursday, November 5 at 6 PM (Mountain Standard Time). Join me as we take a virtual river trip along the Colorado River in Grand Canyon. I will be highlighting some of the many attractions that can be found on this amazing trip, using some of my best images from trips taken in the last 15 years. Hopefully, next year we can all run the river for real. But in the meantime, come run the river with me - virtually!

Thank you and see you "on the river" November 5!

Virtual Grand Canyon River Trip
Thursday Nov. 5, at 6 pm Mountain Standard Time (8 PM Eastern; 7 PM Central; and 5 PM Pacific)

Ticketed online event, $12 for members/ $15 nonmembers

Take a Grand Canyon river trip with renowned geologist and long-time river runner Wayne Ranney, all without leaving home! Ranney will share images of the geology, archaeology sites, and waterfalls on the Colorado River. This is a fundraiser to support the Museum of Northern Arizona.

Thursday, August 20, 2020

Update on A Newly Exposed Trackway Along the Bright Angel Trail in Grand Canyon

Artists rendition of how the new trackway was created (Figure 8 in the paper). Art by Emily Waldman.

I have posted a second addendum to my original post from December 11, 2016. A new paper describes this trackway in detail! See the addendum here.

CNN also picked up the story here.

Monday, August 17, 2020

Jellyfish Sprite Captured by Camera in Texas

 McDonald Observatory

On rare summer nights, ethereal forms leap into the skies above distant thunderstorms. Alien invaders? Not quite: it's a jellyfish sprite, an extremely brief and rarely captured event associated with incredibly powerful lightning strikes. This event lasted less than 1/30th of a second and occurred above a powerful storm about 100 miles away as seen from McDonald Observatory on July 2nd, 2020. 

Image Credit: Stephen Hummel

Tuesday, July 28, 2020

Images from Curiosity on Mars

The Mars rover, Curiosity, has been roaming the Gale Crater for 8 years - it was only supposed to be operating for 2 years. This ten minute video is amazing! They have taken thousands of images and spliced them together to make it look like a video. Outstanding !

Watch here.

I understand that if folks are not in tune with desert landscapes that the video may appear bleak. However, looking at an alien planet ironically brings life to the images. Geologically, we see the similarities between our home planet and the Red Planet - sand dunes, limestone, tilted strata, sandstone, and skylines. Try not to let the barren nature of this "other world" taint your appreciation of the wonders of the solar system of which we are finally beginning to understand more deeply.

Self portrait of the Curiosity rover. I support interplanetary exploration!

Friday, July 03, 2020

Remembering Hugh and Ruth Downs - Fellow Travelers to Earth's North Pole, 1998

From left to right, Hugh Downs, Ruth Downs, Herbergers, and Buzz Aldrin.

You may have heard that Hugh Downs, longtime TV personality at NBC and ABC, passed away on July 1, 2020. His obituary was published by the New York Times on July 2. I was fortunate to travel with Hugh Downs, his wife Ruth, and their friend and colleague Buzz Aldrin to the North Pole in July, 1998. He was filming a segment of the ABC program "20/20." Mr. Downs had previously filmed a 20/20 segment at the Amundsen-Scott South Pole Station in Antarctica and wanted to round out his "far-ends-of-the-earth" résumé by filming a segment at the opposite end of the earth.

In a previous blog posting celebrating the Centennial of statehood in Arizona, I included a picture taken with the Downs' and Buzz Aldrin at the North Pole. The link to that posting can be found here. We were traveling by nuclear-powered ice breaker on the Sovietsky Soyuz through Arctic ice on a 14-day expedition. I was working onboard as a geologic lecturer for TCS World Travel on the trip. 

Ruth (Shaheen) Downs passed away in 2017 and her obituary can be read here. She was a very gracious person on our voyage and Hugh credited her with much of his success. Ruth was quite successful in her own right and I want to remember her passing as well, since she likely escaped much of the limelight when she passed in 2017. They were together for 75 years!

On our voyage, I found Hugh Downs to be an excellent listener, curious, and gracious to all of the passengers on the trip. The well-known Herberger family of Phoenix were also along and our group formed a sort of Arizona contingent on the trip.

I tried to find a link to the 20/20 segment that was filmed at the North Pole, with no luck. If any readers have such luck - send me the link and I will include it here.

Tuesday, June 30, 2020

Meanders, Oxbows, and Time

My colleague, Brad Dimock, sent along a link recently that I know you will find interesting. It involves a cartoon graphic that shows the way mature rivers meander and evolve through time. You will see meanders turn into oxbow lakes that are cut-off from the main stem, then fill with sediment. You will see point bars grow as meander loops arch outwards. You could look a this for a half hour and not see enough. The site was constructed by Robert Hodgin. Watch it here. Thanks Brad!

Here are photos I took of the upper Amazon River near Iquitos Peru in September, 2009. You can easily see the meanders and oxbow lakes. Imagine that these are migrating and moving just like in the graphic above, but on a much slower pace. 

Saturday, June 20, 2020

Why no blogs...?

Palisades of the Desert from the Colorado River, September 17, 2013
I think everyone will agree it has been a difficult few months. While I weathered the pandemic and its consequent isolation fairly well in March, April, and May, I seemed to falter a bit in June. I miss traveling. I miss lecturing. I miss being on the river looking at the Grand Canyon. I know it is difficult for many of us right now. But we have to keep in mind that we, as a species, aren't calling the shots right now. That can be difficult for some - to admit that we are helpless against nature. But why should we be against nature. No matter how difficult it is for the both of us here, we are doing what we can to limit the spread of the virus. We do it for us. And we do it for others. It has been especially hard on my wife not seeing the children or grandchildren. But we want to be good citizens.

There are really two reasons why I have not been blogging since the end of May. The first is that there is nothing to say. I haven't been anywhere, haven't done anything. So why force it. I can take a break - I hope you will stick with me until we come out on the other side. The second reason is that I have been working on a project. I am a co-author on an upcoming geologic river guide for the Grand Canyon. Since the end of April, I have been plugging away at the keys of my computer, transferring my river observations into readable text. A sample spread is included below. There will be a geologic map on one half of each spread and a mile-by-mile description on the other half. My co-author is Dr. Ryan Crow at the USGS here in Flagstaff and the book will be published by them. I am excited to be working with Ryan - he has researched the lava fields found in western Grand Canyon and brings great expertise to the project.

I am hoping the guide will be ready for the 2021 river season. For that to happen, I will have to take significant time away from blogging and dedicate that time to finishing the guidebook. I will try to post something now and then from previous trips, and I may even dip into my vast collection of photographic slides from days long before this blog existed. There are some good ones. But right now I need to focus on the book and maintain some sanity during the necessary isolation.

Just letting you all know there may be less blogging through the summer. My enthusiasm for travel, geology, landscapes, and exploration remains high. Thanks for your understanding.

Saturday, May 16, 2020

Cratering - Marking the 40th Anniversary of the Mt. St. Helens Eruption

Photomural image by Richard Gordon Bowen, May 18, 1980. Courtesy of the Bowen Family.
May 18, 1980. If most people remember this date at all, they will recall it was the sunny morning that Mt. St. Helen's in southwest Washington's Cascade Mountains let loose with a powerful blast that tragically killed 57 people. The 40th anniversary of that eruption is this Monday, May 18. I found out about the blast upon ending a river trip in the Grand Canyon. But first...

... The Portland Art Museum is sponsoring an exhibit to commemorate this historic geologic event. I learned of the exhibit, now viewable virtually and online, through my friend Dixie Watkins and his wife Elaine. They sent me a link that will take you on this virtual tour, which is outstanding! This is the preamble to the exhibit and tour:

"The Portland Art Museum proudly presents this tribute to Mount St. Helens on the fortieth anniversary of the eruptions of 1980. Spanning the period from 1845 to the present, this exhibition is the first survey of works of art inspired by the mountain. Although 175 years is barely a blip in geologic time, the art bears witness to an extraordinary era in the long, cyclical life of the volcano. The beauty of Mount St. Helens has ranged from bucolic to savage. Before the eruptions, painters delighted in depicting its pleasing conical shape rising high above the verdant landscape. The 1980 eruptions challenged artists to capture the thrilling and terrifying displays of nature’s sublime power. When the smoke cleared, the new apocalyptic face of Mount St. Helens compelled the depiction of its haunting majesty. Since then, the rapid return of life to the mountain has captured the attention of photographers as well as scientists from many fields. Although the volcano seems to have reclaimed its serenity, some artists have begun to look to the future. Mount St. Helens will erupt again. We are pleased to welcome you to this celebration of a great wonder on our horizon."

*** You can view the virtual exhibit at this link:***
Paul Kane, 1810–1871) Mount St. Helens, 1849–1856. Oil on canvas. Royal Ontario Museum, Toronto
I remember the day 40 years ago. I was rowing for the very first time a raft down the Grand Canyon. It was a US Geological Survey research trip with veteran geologist Don Elston leading the way. Don was studying remnant paleo-magnetism recorded in some of Grand Canyon's rocks and he conducted river trips to access the sites. Before this trip began, he was short one boatman - and in the final moments before the trip began.

Don had open heart surgery just six months before this trip, which was to be his first since his operation. He was excited and perhaps just a bit anxious about the trip. His wife Shirley and nephew Charlie were on the trip as well.
Gary Mercado, a fellow geology student with me at Northern Arizona University, had previously rowed boats for Don in these studies. But just before the trip began, Gary received word that he got a job with the USGS in Denver. We had both just recently graduated with geology degrees the week before the trip began but now Gary needed to decline his previous commitment to row this trip. Luckily for me, he asked if I was interested in being his replacement. I jumped at the opportunity, not giving it a whole lot of forethought. In those days, I said yes to anything that sounded good, oftentimes not thinking it through (like the one and only time I jumped out of an airplane in 1976).
Gary put me in touch with Don Elston and before I knew it I was rowing a boat down the Grand Canyon!

Up to this point I had only been a passenger on the river in Grand Canyon and that was just half of a trip from Phantom Ranch on down. Like everyone else back then, you learned by doing - just get in the row seat and go. Do what I do. So after the trip started and we would scout a rapid, people would ask me what that particular rapid in Marble Canyon looked like. Not wanting to appear inexperienced, I quickly came up with the honest, but incomplete answer, that, "I've never seen this rapid at this level of water." It seemed to work. (Although to this day I'm sure many of those intelligent folks figured out that I was the new guy. I was so scared from the get go and I made too many mistakes. But I was thrilled for the opportunity to row a boat and there were so many big name geologists that were along on the trip. I remember one - Max Crittenden, one of the first geologists to ever describe metamorphic core complexes. There were others whose names I have now forgotten.

Many interesting events happened on this trip. This was the year that Glen Canyon Dam filled the Powell reservoir for the first time so there was 30,000 cfs coming down the river. It was HUGE! I was rowing a very large 22' snout boat with 12-foot oars. As skinny as I was in those days, and with no prior rowing experience, I couldn't really control the boat. One day, camp was to be made at the Clear Creek beach but I missed the pull in. Don wanted to walk up to the horizontal waterfall and look at some rocks there. It was late in the day we were to camp there. But because I missed the pull-in, we had to continue down to Phantom Ranch.

There was no way to camp there for river parties but we did take time walk up to the Ranch so Don could make a phone call. While we were there, I encountered my old Park Service boss, who was giving an orientation tour of the Ranch to the brand new Superintendent of the Park, Dick Marks. I was not on good terms with my old boss and as the formalities were exchanged between the various members of our group, I eyed my ex-boss warily, as he did me.

We left Phantom but it was too late to go vary far, so we had to find a camp fast. We stopped just a few hundred meters downstream on a cobble beach just across from the River Trail. It was illegal for river parties to camp there in those days but we really had no other choice. It was getting dark and Horn Creek Rapid loomed ahead just two miles. While we setting up camp, wouldn't you know it, the two rangers we saw at Phantom Ranch were hiking up to Indian Garden on the River Trail and stopped across the way to look at our camp. They knew who we were. When the trip was over, Don received a citation in the mail from Grand Canyon National Park for illegal camping. For years afterwards, Don always joked that the citation was labeled "Department of the Interior vs. Department of the Interior".

A few days later, I got into an eddy I could not row out of. It was just above Tapeats Creek. Round and round we went for at least 20 minutes and I became thoroughly exhausted. Finally, one of the younger geologists in my boat stepped in next to me and we each took one oar and finally made it out. Man that was big water!

Albert Bierstadt (American, born Germany, 1830–1902). Mount St. Helens, Columbia River, Oregon, 1889. 
Oil on canvas. Collection of L.D. "Brink" Brinkman, LDB Corp, Kerrville, TX

On May 18, 1980, the day that Mt. St. Helen's blew its top, we were blissfully unaware of it and getting ready for our run of Lava Falls Rapid, the biggest, meanest rapid in the whole canyon. To say I was scared to run this monster for the first time would not convey in a proper way how I felt. I was terrified. And apparently, Don had a history with this rapid that caused his wife Shirley to begin to fret as much as me. While we scouted the rapid, it was determined that Shirley would ride with me on the biggest boat, and Don's nephew,Charlie would ride in the smaller boat with him. Remember, this was just six months after Don's open heart surgery.

Finally, I got in my boat. I was hyperventilating as I pulled away from shore and entered the tongue of the rapid. I guess I was lucky to have such a large craft but one still needs to bee spot-ion for the entry through the tongue. And myriad swirling currents play havoc on smaller boats in there. I remember very little about the specific run I made. Someone on shore took a movie picture of it and I have a copy of that somewhere. But it must have been a good run because I don't remember it! At the foot of the rapid I had a hard time stopping but eventually pulled over on the left bank below Prospect Spring. We couldn't see the rapid from there but waited for the other boats in our party to come down.

As we bobbed in the eddy below the spring, time seemed to drag on forever. Where were they? Before long, Shirley started to worry that no one was coming down. "Where is Don," she repeated. I tried to comfort her as best as I could. But I started to worry as well. Shirley hadn't wanted Don to row this trip so soon after his surgery and wanted to be on the trip with him. She worried audibly that something bad had happened. I tried to calm her down.

Meanwhile, up north, Mt. St. Helens was roaring with its gigantic blast. We would not find out until the trip was over what happened, although we were all talking about it on the trip, as it had been rumbling for months. All geologists back then were excited about what might happen with the volcano.

Finally, we saw something coming down the river. It was an ice chest bobbing in the water. Uh-oh. Something else came along just after that - a life jacket! Oh no, that's not good. Shirley started to cry. I immediately pulled out into the current of the river to be of assistance anyway I could. Just by chance at that time Don came by my boat bobbing in the water. Charlie was very close to him trying to reach him in case he needed help. I pulled them both into my boat as we began to go through Son of Lava Rapid. Someone in another boat wrangled his boat ashore. He had misplaced his position in the tongue of the rapid, the swirling currents grabbed his keel and he ran right over the ledge hole! No man's land!

Forever afterwards, Shirley Elston thought of me as the one who saved her husbands' life. For the rest of our friendship, spanning many decades, I could do no wrong. She and Don took that day at Lava Falls all the way to their graves and I was honored to be invited to Don's memorial. I remain forever grateful to them both in giving me the chance to be a boatman in Grand Canyon.

Look at the online exhibit and remember Mt. St. Helens 40 years on!

Frank Gohlke (American, born 1942). Aerial view: Landslide—debris flow area—looking east toward Spirit Lake, 
5 miles north of Mount St. Helens, 1982; printed 2005. Gelatin silver print. Courtesy of Artist and Gallery Luisotti

Thursday, May 07, 2020

More Cratering in Northern Arizona - Rattlesnake Maar

Photo by Dawn Kish - From the top of the Rattlesnake scoria cone; the reddish arc behind the figure is Rattlesnake maar
An unusual and little-known landform on the eastern side of the San Francisco Volcanic Field is the Rattlesnake maar near Winona Arizona. As the Covid-19 pandemic set in, some friends, my wife and I decided to visit nearby volcanic craters — to get exercise, breathe fresh air, and hone our geologic skills. (Admittedly, I was the only geologist on these excursions and none of the others wished to hone anything of the kind. Yet they at least admitted to wanting to know more)! When I was a graduate student at Northern Arizona University in the 1980s, I took a class called Volcanology and the lab consisted of visiting a different volcano every week! It was the best lab class I ever had. Rattlesnake maar was one of the features we studied.

View of the west side of the maar where the truck is parked. We are on the rim of the maar at this location and simply walked up the gentle slope on the two-track road around to its crest. The snow-capped San Francisco stratovolcano lies in the distance to the west, with other cinder cones in between. Cinder is a term in common usage but geologists also use terms such as lapilli and scoria. All are any pea-sized ejecta that forms when droplets of molten lava are thrown into the air and cool and harden. Scoria contains more vesicles, being the basaltic equivalent of pumice. Thus, the cones can properly be referred to as cinder cones, lapilli cones, or scoria cones.

On top of the Rattlesnake maar looking west. Note the dip of the tuff to the north (right) that was thrown out when the maar erupted (see my detailed description of maar eruptions below).

Looking south to the scoria cone that formed after the tuff cone. The evidence for this is that the southern part of the tuff ring is buried beneath the scoria cone. This was a great hike. For the geologist, I include the next section on maar volcanoes.

Maar's are broad, low-relief volcanic craters found not uncommonly on Earth's surface. Check out this Wikipedia site for some examples of maar's found around the world. They form when hot magma rises into the upper crust and interacts with water. On continents this usually is groundwater but can also be lakes or rivers. When the magma encounters the water a phreatomagmatic eruption occurs. These are violent steam ejections that emplace tuff around the vent. Krakatoa in Indonesia, which erupted in 1883, is an example of an especially large and explosive phreatomagmatic eruption.

Geologists are also interested in the subsurface structure of maar's. The diagram above is used courtesy of Dr. Steve Semken at Arizona State University. It shows a typical carrot-shaped diatreme that underlies a maar volcano. One of the most famous exposed diatremes is Shiprock on the Navajo Nation in New Mexico.

Dr. Semken created this cross-section that places two different, but nearby surface features one on top of the other. They share a common ancestry but one (Shiprock) is the more deeply eroded feature. In other words, before Shiprock was so deeply eroded, it was covered by something akin to the Narbona Pass crater.

Dr. Semken, along with colleague Larry Crumpler of the New Mexico Museum of Natural History, also created this photo collage of the two features. On the bottom is an aerial photo of Shiprock with its presumed diatreme margins added. These project upwards into a second aerial photo of the Narbona Pass crater. I think this image really relates two different parts of maar formation.

This is an excerpt of the USGS geologic map - MF-1960. I have colored some of the pertinent features using the Macintosh Keynote program. The tuff ring of Rattlesnake maar is colored dark purple. Note how it is not present on the south. The Rattlesnake scoria cone is colored lighter purple and overlaps the presumed southern portion of Rattlesnake maar. The brown color denotes the lava flows that issued from the scoria cone and that flowed down the regional slope. Another scoria cone and associated lava flow (not colored), Merrill Crater, can be seen to the east of the Rattlesnake cone.

The map is called "Geologic map of the east part of the San Francisco Volcanic Field, north-central Arizona." You can access the USGS map here:  MF-1960

More cones to come! Thanks as always for reading.

Thursday, April 30, 2020

Moon Crater, San Francisco Volcanic Field, Northern Arizona

The next destination in the series, "We Are Cratering in Northern Arizona" is Moon Crater. This volcanic center is labeled as Crater 170 on Harold Colton's 1936 map in "The Basaltic Cinder Cones and Lava Flows of the San Francisco Mountain Volcanic Field" (republished in 1967), and as Vent 3031 on the USGS "Geologic Map of the East Part of the San Francisco Volcanic Field, North-Central Arizona." You can access the USGS map here:  MF-1960.

*** Note to any would-be visitor to Moon Crater: The eastern half of the cone is on private land and only the western half is open to the public as part of the Coconino National Forest. The red and green lines on the map above only denote a walking route used by the local landowners. 

 Panoramic view of the interior of Moon Crater looking east.

Annotated panoramic view of the photo above. The yellow line depicts the rim of Moon Crater. A secondary cone erupted within this larger feature and is outlined in red.

Five cinder cones are depicted in this excerpt from the USGS map MF - 1960. Moon Crater is the circular feature at bottom center. Qbb represents basaltic rocks that have normal polarity (meaning younger than 780,000 years) and are latest Pleistocene in age. The are rocks that form the cone inside the larger crater (red outline in the photo above). Qbbt represents basaltic tuff of the same age, forming the rim of Moon Crater. Qbsbp is Sunset Crater tephra that landed in the bowl of Moon Crater. It is assumed that the same deposit is already stripped from the rim of the crater.

View to the northeast from the rim of Moon Crater. Merriam Crater is the cone seen in the distant background. It may be the source for the lava flow that created Grand Falls (or the flow may have come from The Sproul, the small, dark, cloud-covered cone in front of Merriam's right shoulder.

A likely fulgurite where lightning struck a rock on top of Moon Crater and melted the heated portion.

View to the southeast of a series of beautiful cones and craters.

View to the northwest. The flat-topped mesa in the far distance is Gray Mountain.

The lone cone in the distance is Roden Crater, where artist James Turrell is shaping the entire cone into a work of art. Look at the web site here and be sure to let each page run the film (three pages).

The rocks on top of Moon Crater have been around long enough to have ventifact surfaces. These are surfaces shaped by particles that blow in the wind and abrade the rock surface.

Late afternoon light on the rim of Moon Crater.

A closer view of the north rim of the crater (foreground and skyline) and the slightly younger interior cone (right).

Descending down to the vehicles. Note the ponderosa pine trees in the valley below. This elevation marks the boundary between the ponderosa and Pinyon-Juniper eco-zones. Next on the tour is the Turkey Hills.

Sunday, April 26, 2020

We Are Cratering In Northern Arizona!

Winter photo of SP Crater, the 4th youngest cone and crater in the San Francisco Volcanic Field. It has recently been re-re-dated at about 60,000 to 70,000 years old. (Photo January 1, 2011)

You might think this blog title refers to a plea for mental health during the global pandemic. But while the heading is pandemic related, it actually involves a more in-depth exploration of various volcanic craters and cones located around my home nestled within the San Francisco Volcanic field. With all of my river trips and international excursions postponed or outright cancelled, we are positioning in place under wide-open skies of northern Arizona. And the Coconino National Forest is currently still open for exploration off trail. A group of friends and I are exploring!
Sunset Crater (Crater 41) is the youngest volcano in the San Francisco Volcanic Field and a recent redetermination of its eruptive date is constrained between 1085 and 1090 CE. You can read the paper that describes this new date here. The original date of 1064 BCE can be found in this reference.

Crater 36 - April 25, 2020
Dr. Harold S. Colton, the founder of the Museum of Northern Arizona catalogued most of the more than 600 volcanic cones and craters within the field. He gave number to many cones that had no otherl names. Crater 36 is a rather indistinct cone in a field of many cones. But it provided a beautiful hike nonetheless on a clear, April day.
The approach to the crater has views of rather mature ponderosa pines. The north flank of the San Francisco Mountain composite cone can be seen in the distance.

This is a panoramic view to the northwest from the top of Crater 36. From left to right you can see the San Francisco Mountain composite cone and dozens of rather young scoria cones. US Highway 89 is the linear gap in the trees.

The coarse cookware pot remains from the occupation of the Sinagua cultural group, which inhabited the area between 700 and 1200 CE. To understand how these people may have been affected by the Sunset Crater eruption of 1985 CE, see this paper.

A view from the west rim of Crater 36 toward the east and to O'Leary Peak, a dacite dome volcano (Crater 23 of Colton) with a K-Ar age of between 240,000-221,000 years.

Panoramic view of the interior crater.

There was early logging inside this crater and the stumps remain in this dry climate. In fact, modern-day ecologists can easily map the tree density in this forest from the time before logging began in the 1880s. This mature ponderosa was cut using a two-man cross-cut saw, as can bee seen by the bi-level cut on top of the stump. The limb debris from this felled tree lies in the background. The tree was cut likely about 120 years ago.

Medicine Valley in the middle distance. This was a wonderful hike! Next up - Moon Crater.