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!