Tuesday, April 13, 2021

To the Rim of SP Crater


Of the more than 600 scoria (or cinder) cones within the San Francisco Volcanic Field, SP Crater stands out as the steepest of them all! One reason for this  is that its final eruptive phase delivered molten lava that welded into dense agglutinate that caps its rim. This hard carapace protects the top and steepens its sides. SP Crater is likely the second youngest crater in this volcanic field (Sunset Crater is the youngest) and has recently been dated at about 55,000 years old. On April 7, I visited and climbed this unique cone, located about 35 miles north of Flagstaff.


A Google Earth image of SP Crater. The image clearly shows the crater and its spectacular set of lava flows that erupted from its base and flowed downhill to the north (top). Note the variations in color on top of the lava flows - the older (and broader) of the flows are weathered and support grasses that appear as green-gray patches. These are seen mostly around the flow margins where the quenching of the lava produced lava levies. There are two lava lobes on the west (left) margin that spilled over these natural levies into a low-lying valley. Younger flows on top of the older flows are not weathered enough to allow for grasses and they appear jet black on top of the older flows. There are least eight other scoria cones in this image that are much older and much more weathered that SP Crater. Some of these have elongate rims suggesting structural control of the vents. The light color in the upper left is the Kaibab Formation bedrock.

The hike I undertook with friends began on the west side SP Crater (left) and generally switchbacked up to its western rim. Then we hiked around to the south side of the rim. 

This is where the young rubble from SP Crater rests on the older material of an older cone.

Brad and Dawn on the indistinct social trail that climbs the west slope.

Volcanic bombs are seen on the slopes of the volcano. One would not want to be hit by one of these dense blobs of 1000°C  lava.
 
After achieving the top of the cone, a fantastic view to the south is obtained. In the far distance is the San Francisco Mountain stratovolcano. In the middle distance with a deep shadow in Colton Crater. It is a next on our tour of craters in Northern Arizona.

Close-up view of the agglutinate rim of the volcano. This hard carapace protects the unleaded scoria that lies beneath it. Through time the slope beneath this likley becomes oversteepened.

The agglutinate likely once completely covered the surface of the inner crater. It is now being undercut as scoria slips downward, causing the agglutinate cap to collapse. A possible sequence of events at SP Crater would be construction of a cone, possible phreatomagmatic eruption to create an inner crater, then fountaining of lava to produce agglutinate, and finally a lava leak in the north side of the cone to produce a lava flow.

More volcanic bombs lying on the rim.

Beautiful clear skies in an enchanted landscape.

Shadows begin to creep in from the west across the volcanic landscape.

On the way down and toward the lava flows. 

Saturday, March 20, 2021

Icelandic Volcano Erupts!

To watch a Live Feed from a camera set up across from the eruptive center, click here. This is really spectacular.

Watch a video taken from a drone flying over the volcano here.

Hey geology enthusiasts! Scientists in Iceland now have established a camera with a Live Feed on the Thanks to my colleague and volcanologist Kirt Kempter for this link. I have an Icelandic cruise scheduled with Smithsonian Journeys in July - I hope we get to go and see this!

Screen capture of the Live Feed taken at 15:35 MST on March 20, 2021. This could be real exciting - hopefully not too exciting for the wonderful Icelanders. The last time this volcano was actives was approximately lately 6,000 years ago, although a nearby eruption happened 781 years ago (in 1240 AD). People were living in Iceland in 1240 AD but not in 4,000 BC. Friday night's initiation of surface volcanism culminates a three-month-long period where over 50,000 earthquakes have been reposted. These earthquakes were likely due to the magma below slowly rising to the surface.

The volcano and current eruption in daylight. Lots of lava is spilling onto the ground. This is a view from March 21, 2021.

Here is the volcano five days later on March 26, 2021. Lot's of growth in the cone from splatter and flows.

Here is a YouTube video of someone who was very close to the eruptive center. These look like aa (blocky) flows at the lava front.

See the Smithsonian's Global Volcanism Program page about the Reykjanes Peninsula here: https://volcano.si.edu/volcano.cfm?vn=371020. This peninsula is where the International Airport is located. However, that does not appear to be in immanent danger at this time.

ADDENDUM: My colleague Kirt Kempter keeps sending me wonderful videos that are made from near the edge of the eruption. This one is really good from a reporter who hiked one hour right up to the edge of the lava flow. I did see some pahoehoe textures in the lava front in this video. Iceland does have lax personal responsibility laws.

Wednesday, March 17, 2021

Box Canyon and Painted Canyon Along California's San Andreas Fault

Painted Canyon in the Colorado Desert of California 

I recently visited the Colorado Desert in Anza-Borrego State Park, California, where I met up with friends to explore the backcountry. On the way to the park, we hiked in Painted Canyon, located adjacent to the San Andreas fault and where young sediments have been crumpled by the fault movement. Once inside the Park, we hiked in Borrego Palm Canyon, Indian Canyon and the Valley of The Thousand Springs. Along the way, we saw evidence for ancient Lake Cahuilla. There is much to see in this part of the world.

View to the west along the Box Canyon Road off of Interstate 10. These Pliocene and Pleistocene strata have been deformed as the San Andreas fault causes rocks on either side to become compressed.

Entering Painted Canyon as it slices through the Pliocene and Pleistocene Palm Springs Formation. These sediments were derived from local granite outcrops and were deposited in a non-marine alluvial setting as the San Andreas fault opened up a basin. This is within the Mecca Hills Wilderness Area (BLM land).

The young sedimentary rocks are underlain by unnamed Proterozoic gneiss and migmatite rocks. Here you can see the obvious unconformity as we walk up the canyon. Note the topography cut into the crystalline rocks below and filled with sedimentary debris.

Around the bend in the stream bed, the contact is seen dipping down so that we can get a better look.

Sure enough, this really Great Unconformity is right there for us to see and touch. The difference in age between these these two rocks is no less than 500 million years and may be over 1800 million years. 

The textures in the old rocks was truly spectacular.

There are a few knickpoints in the stream bed but ladders are installed to get around them. 

Just above the contact of the two rock units are conglomerate lenses where small channel fills left pebbles and cobbles.

What a lovely hike and if you find yourself in Joshua Tree National Park nearby, I can recommend a hike in Painted Canyon and a drive in Box Canyon.

NOTE: This Wilderness area is adjacent to a very large population near Palm Springs and in the agricultural Coachella Valley. Therefore, it is constantly under threat from activities that may be considered non-compliant with Wilderness values elsewhere. As our society grows and multiples, many of our protected areas will come under similar threats. However, I believe that we must encourage and include wider and larger constituencies for the outdoors in general and Wilderness in particular. Some of the people we saw in this canyon were not "typical" Wilderness users with Columbia shirts and hiking pants. Yet they were enjoying the resource in appropriate ways. I add this note to begin a discussion on how we can grow larger constituencies for Wilderness values!


Saturday, February 20, 2021

Earth's Changing Climate Highlighted in Atlantic Article

The Atlantic recently published an article called, "The Terrifying Record Lurking in Earth's Ancient Rock Record" by Peter Brannen. I highly recommend reading the article to get a flavor for the many interesting (and sometimes frightening) changes that have occurred in Earth's climate since the end of the Thermal Maximum about 55 million years ago. You can read the article here.

The article is a nice synopsis or review of Earth's climate since the dinosaurs went extinct, at a time when Earth's climate was much warmer. I think it could be used as a primer on seminal events that we know happened in the geologic past. 

I really like seeing geology get this much press! 

In the end, I think long and hard about our attempts to control the climate. Even if we were not the cause of the current climate change, our geology would inform us that this change has been ongoing and is a huge shaper of all living things. When we as individuals were born, the depth of knowledge concerning how the Earth operates was unknown. We were still just identifying the various “parts” that came with the planet. Our lives have commenced with the progressive “assembly" of these disparate parts with the result being something far different than the disassembled parts could convey. We have lived through a revolution in Earth knowledge, such that its immensity has not yet truly sunk in to us as a species. This article attempts to help us understand the long arc of Earth history and to connect the dots. What a scary, beautiful, unpredictable planet system we have been born into!

Wednesday, February 10, 2021

To the Border in Organ Pipe Cactus National Monument

In the final ten days of January, Helen and I traveled down south to the beautiful Sonoran Desert. I had been invited by the interpretive rangers and resource managers at Organ Pipe Cactus National Monument to do a little geology instruction for seasonal rangers. I was honored to be asked by their Chief of Interpretation, Jessica Pope. Organ Pipe is a spectacular desert landscape that I first visited in the late 1970s. It is known mostly for the odd columnar cactus that gives it its name and that enjoys a habitat that barely makes it north across the international boundary with Mexico. In this post, we'll learn a bit about the landscape there, one of the major springs in the area and see photos of the newly established "wall" along the border.

Part 1 - The Approach

Our trip began with another volunteer gig - working at the Covid-19 vaccination site at State Farm Stadium in Glendale Arizona. Here Helen is getting trained on using the iPad for checking people in. The cars in the background are being verified at the first station. If everyone in the vehicle has a valid appointment for that day, they are waved to the right and into the inoculation lanes. If anyone in the vehicle did not have a valid appointment for that day (but at least one person did), they were sent to one of our lanes (10 in total). It was nonstop vehicles for us from 2 to 10 PM! It took about 10 minutes to check each person in - we estimate that we checked in at least 40 vehicles and 50-60 people on our shift. Still, it was worth it to help out!

Our next stop was Tucson to see our grandson Jordan, attending the University of Arizona as a pre-Med student. While we were there, it snowed! Not a totally unheard of event in Tucson but it doesn't happen every winter.

On the way from Tucson to Organ Pipe, we passed desert ranges with snow coming all the way down to the highway. These are the Coyote Mountains, southwest of Tucson.

Along the way we saw this cristate or crested Saguaro cactus. See this National Park Service site bulletin that explains this odd growth pattern in the cactus.

This is the map of Organ Pipe Cactus National Monument, which is about 330,000 acres (133,550 hectares). Our training drive went on the Puerto Blanco Drive, shown on the map beginning at the Kris Eggle Visitor Center (green banner) and we traveled anti clockwise on the road shown in black, making stops along the way. NOTE: That the round trip on the Puerto Blanco Drive is currently closed to all visitors during "wall" construction. I was allowed to journey on the road with NPS personnel for the interpretive training exercise. This road may reopen in March or April. Please check at the Kris Eggle Visitor Center for all current information about road closures. 

A nearly full moon rises over the Ajo Mountains and young saguaro cactus (Carnegiea giganticus). Even the folks in Saguaro National Park near Tucson admit that Organ Pipe has more robust stands of these desert giants. And it is the young ones that seem to dominate here. It is about 75 years before they begin to grow arms.

Part 1 - The Puerto Blanco Drive

Leaving the Kris Eggle Visitor Center and heading north on Puerto Blanco Drive. The pavement ends after a few hundred meters. That is Pinkley Peak straight ahead in the distance, composed of mid-Miocene (about 17 Ma volcanic rhyolite tuff and lava).

Readers of this post will find a copy of a geologic map of Organ Pipe Cactus NM at this link. There is a KMZ file available in the link, which opens an interactive geologic map in Google Earth. Users can click on any colored rock unit and find a description of it. The legend for the various rock units is there was well. On this image, I have zoomed in to a section that includes the Puerto Blanco Drive that we completed on January 27, as well as two hikes in the Monument. Check out the map using the link above.

This was the location of our first hike to Dripping Spings. Note the ash flows and tuff in th background.

Dripping Springs in a small alcove of rhyolite rock.

The view back to the northeast and the valley floor. Over 70% of the Monument is covered by alluvial fill. Therefore, the rock outcrops are the lesser part of the landscape. Similar rocks underlie the valley fill bit were downdropped during the Basin and Range Disturbance, which affected this area after about 16 Ma. The rhyolite eruptions that produced these rocks ceased shortly after their emplacement and were pull apart as the transform morion of of the proto-San Andreas fault began.

Organ pipe cactus and the Puerto Blanco Mountains.

Rijk Morawe is the Resources Manager at Organ Pipe and led the field trip. He has worked here for nine years and loves it. His passion for the place is infectious. The other folks are seasonal interpreters who wanted to improve their geology skills.

This is the Golden Bell Mine. Note the quartz dike behind the metal-covered shaft.

The trend of the quartz dike to the northeast.

We stopped for lunch at the old Bonita Well. 

This is the junction of the Puerto Blanco Drive with the Pozo Well Road. The view is north along Pozo Well Road. This is where the Puerto Blanco Drive is closed to further travel at this time due to construction of the "wall." Note the safety beacon in the background. If someone is lost in the desert and out water, food or shelter, they can press a button on this antennae and the Customs and Border Patrol will hurriedly come to greet you.

Warning sign of illegal activity.

And then we arrived at the International Border. This "wall" has been constructed within an eight-month period. You may have noticed that I have placed the word "wall" in parentheses throughout this posting. That is because I think it is more properly called a fence. A wall is something one cannot see through.

You can see through the bollards and so technically, it is not a wall but a fence. Solid metal sheets makes up the top four feet or so. It must be able to stand up to attacks from sledgehammers, pick axes, torches, and other tools for at least 30 minutes.

It is a very high fence at 30 feet!

Tom holds a cross-section of one of the bollards. They are set about 6 feet into the ground (concrete) and then the space is filled with the same.

These gates are meant to let monsoon flood water through when needed. I'm not quite sure how they operate? There is no question that the fence was constructed much too quickly. No matter what your feelings may be about the border, immigration, or illegal entry into our country, the fact that environmental studies were curtailed for this project means that a satisfactory understanding of the natural landscape and its many nuances is lacking. Any sheet wash flood will wreak havoc on this fence. Not to mention that it is barrier to wildlife migrations and water. The fence is a short-sighted attempt to fix an admittedly big problem. I have traveled to many different countries and see how their immigration systems work. We do not even have an immigration policy at this time. The fence is interesting but not for reasons that are beneficial.

Along the fence.

We gave three feet of our country to Mexico with this fence. As I peered though the bollards, I could see one of the original boundary obelisks for the border. Check out this story in The Guardian about these.

Right along the border is Quitobaquito Spring. I first visited here in the late 1970s.

It is a wonderful oasis in the desert. This is a panorama shot of the basin that was carved out by ranchers in the 1930s. The distance across is about 150 feet.

Rijk talks to the group about the importance of the spring. I wanted to show the proximity of the International Boundary to the spring. When I first visited here in the late 70s, there was a three-strand barbed wire fence here. The fence was upgraded in the early 2000s to a vehicle-proof barrier after a Park Ranger lost his life to cartel members. That version of the fence was about four feet high.

The National Park Service has funneled the spring water into the pond as the discharged has gradually been lowered since about the 1990s. Then, nearly 25-27 gallons per minute issued from the spring. It has slowly diminished to about 9 gallons per minute. Still a lot of water for its location but with an alarming trend. Agriculture just south of the fence is likley not the cause and the flow of groundwater is likely from the La Abra Valley to the northeast of the spring.

There are native pup fish in the water here! They are the Sonoyta pup fish (Cyprinodon eremus). See a photo of one in this link. We saw many in the pool behind Helen.

Day 2 - Senita Basin to the Visitor Center

The next day, I went again with Rijk to help him with some of the geology in the Senita Basin. This is the plant that gives rise to the Mexican Jumping Bean, (Sebastiania pavolana). It is actually a larvae, that has been planted into the seeds of the plant by a moth. The larvae wiggle to scare away predators. I remember buying these as a kid in Tijuana.

The basin receives its name from this cactus, the Senita or Old Mans Beard (Pachycereus schottii). This is an even rarer cactus in the USA and the Senita Basin could be its own "Monument Within A Monument!"

Can you see the fence in the distance? We are standing on Laramide-age granite looking southwest.

It was a beautiful day.

The Victoria Mine.

A last view of the Victoria Mine. This was likely a gold and silver prospect that played out enough to have significant infrastructure.

I want to thank the rangers and managers at Organ Pipe Cactus National Monument, especially Jessica Pope, Chief of Interpretation for extending the invitation to us to come and help interpreters, and Rijk Morawe, Chief of Resources Management who led me on two outstanding field trips! This is a gem of a Monument that needs to be a National Park - and soon!