Airliner Chronicles: Stuck on a Plane with a Proselytizer...

And really, I felt sorry for the poor guy who was stuck sitting with me on the plane flight from St. Louis to LAX. Oh, I wasn't trying to convert the poor guy into some religion. No, he got the full-court press from me about the importance of understanding what was going on 35,000 feet below us on the ground. He was being proselytized into the world of geology.

People who fly a lot for whatever region may be forgiven for not paying attention to the grand panorama unfolding below them, but to a geologist, the extra dimension is pure gold. Seeing a large swath of the Earth's surface grants a whole new perspective to understanding geological processes.

I didn't have a working GPS on the flight, so I had to guess our location for the first two hours of the flight, somewhere over Missouri, Oklahoma, or Texas. But it was unmistakable that we were over oil and gas country. The drilling rigs and their connecting roads could not be missed. Some politicians once described the "footprint" of oil and gas drilling on a landscape as just a few acres being torn up. Seeing the scene from above suggests that the footprint is "small" in the sense that a spider web is a few strings of dragline silk.

I was lost until the mesas and plateaus appeared. I knew at that point that we were in New Mexico, and I correctly figured out that we passed Sante Fe and Las Vegas, New Mexico. My seatmate, a Pittsburgh resident, got a bit confused about the Las Vegas part; "We're in Nevada already?". I crushed his hopes (that is NOT the way to proselytize, by the way).

The landscape turned into a rainbow of color, and I suddenly knew our precise location better than a GPS unit. We had reached the Painted Desert area of Petrified Forest National Park in Arizona. A plateau covered by basalt flows was breached by erosion, exposing the brightly colored layers of the Triassic Chinle Formation. The Triassic rocks reveal the beginnings of the dinosaur domination of our planet, and the floodplain and river deposits contain some of the earliest dinosaur species known. There is the wood, of course, and a stunning variety of amphibians and reptiles, including Phytosaurs, huge crocodile-shaped creatures that exceeded 30 feet in length.

Just west of Petrified Forest, I got the finest treat of the day, a perfect view of Meteor Crater. I put the best of the pictures up in yesterday's post.

A short time later, more colorful rocks came into view, but they were older than the Chinle of Petrified Forest. We had reached the Pennsylvanian and Permian rocks of the Supai Group. These rocks are the same ones exposed in the walls of the Grand Canyon, about eighty miles to the north. This is the edge of the Colorado Plateau, where the high flat landscape gives way to the deep fault valleys of the Basin and Range Province. Because the valleys are so deep, erosion eats away at the edge of the plateau, forming scenic deep gorges like Oak Creek Canyon, north of Sedona.

I was distracted by some wildfires burning in the thick forests of the plateau. I finally realized I was missing one of the more extraordinary features of the Colorado Plateau, the San Francisco Peaks Volcanic Field. The field is a vast basalt lava plain populated by hundreds of cinder cones, and an immense stratovolcano that reaches more than 12,000 feet in elevation, the highest point in all of Arizona. The edifice of the San Francisco Peaks has been altered somewhat by erosion; it was once 4,000 feet higher. It would have been the highest point in the lower 48 states.

The existence of the volcanic field is somewhat of an enigma. There's no obvious reason for it being here. There are suggestions that it is the result of an incipient hot spot, but the idea is not wholly accepted. The field is active; an eruption took place less than a thousand years ago.

Somewhere near the end of the flight, my poor beleaguered seatmate asked a geological question. He was wondering why there was a gigantic hole in the ground that wasn't a meteor impact crater. It was an open pit mine, probably for copper. I almost had a convert to the ages of rock!

The Other California: The Volcanoes of San Francisco...

After spending several posts talking about the "volcanoes" of Los Angeles, let's turn our attention to the other famous metropolis of our fair state: San Francisco and the Bay Area. Most people know of the famous association of earthquakes with the city by the bay, including the 1906 event, and the Loma Prieta quake of 1989. But what are the chances of a volcanic eruption in the Bay Area (note: I am using the term "bay area" loosely)? Are there any volcanoes looming about? And really, wouldn't lava in a Hollywood movie look a lot cooler if it were streaming down Lombard Street?

If you want to look ahead at some possible answers, might I suggest the work of Andrew Alden at Quest, Oakland Geology, and About Geology. The Bay Area is his geological beat, and I only pay the occasional visit. Also, don't forget the Interactive Geological Map of California!

So Much for the Green Flash...But is the Coast Toast?

So much for the green flash...the consensus seems to be that I didn't see one, although I stubbornly hope that I saw it but just didn't happen to photograph it...anyway, courtesy of wikipedia, here is what one type of a real green flash, a mock-mirage flash, looks like.

I'm thinking that seeking a green flash and failing like I did is a bit like those first few times panning for gold. You'll see pyrite (fool's gold) a dozen times and think it might be gold, but when you see a gold flake for the first time you'll never misdiagnose pyrite again. I shall keep searching for the green...

I enjoyed the sunset that night immensely. There were all kinds of things going on, in the sky and over the water. The optical effects of a setting sun are always interesting of course. The distortion almost looked like a bomb blast. Or a light bulb...

It was interesting to see the amount of damage that has been done by wave action. This used to be part of the parking lot at Leo Carrillo beach. This is a look at the future; rising sea level and declining supplies of sand can only mean that coastal erosion will be increasing in extent and intensity.

 The seas were calm on this late summer afternoon. The effect was hypnotic and peaceful.

There were dozens of pelicans flying west along the coast line.  I love how they glide just inches above the waves; they are such graceful fliers. The Brown Pelicans almost disappeared in the 1960s as they absorbed so much DDT in their diet that their eggshells weakened and broke. With the ending of the use of DDT as an insecticide in the 1970s their population rebounded strongly.

What a shame it would have been if they had disappeared entirely. Does anyone besides me and Steven Spielberg think that they look like resurrected pterodactyls?

The sun sank below the horizon and the clouds briefly turned orange and pink. We headed back to camp up in the canyon.

I glanced at one of the rocks on the beach that was being used as rip-rap (wave barriers). The holes made me wonder about something. Fifteen years ago a movie was released to a certain amount of derision among geologists: Volcano. Tommie Lee Jones played a gruff but lovable emergency services director, and Anne Hecht played the geologist with the heart of gold. The volcano sucked (literally it sucked: Anne's friend in the movie got sucked down a hole into the lava). There were earthquakes, there were exploding buildings, there were lost children, and melting people.

Obviously, the idea of a volcano erupting in downtown Los Angeles is preposterous. There must not be a volcano within hundreds of miles of the city. I mean, there aren't any volcanic mountain ranges in southern California...right? The faults are all strike-slip and thrusts. It just doesn't seem likely. So how to find out? Maybe, a look at the interactive geologic map of California from the California Geological Survey (clue: most of the volcanic rocks on the map are pink or orange...).

Is the coast really toast, or is it already toasted?

Geological Jealousy: Why don't I get to see this in California?

This spectacular image comes courtesy of Halldor Sigurdsson at Iceland banking crisis news and more, who has been providing some nice coverage of the ongoing eruption at Eyjafjallajokull (you may be sure that I didn't spell that from memory). More pictures and a nice aerial video can be found here. Note the cars parked at the edge of the lava flow. Yeah, I know most people run away from volcanic eruptions, but geologists and I guess Icelanders aren't most people! Erik at Eruptions has a nice rundown of recent activity.

Iceland is a volcanic wonderland, with the activity resulting from the country's location on the Mid-Atlantic Ridge (a divergent plate boundary), and possible location on top of a hot spot, perhaps similar to the one that underlies Hawaii. The precise nature of the conditions resulting in the volcanism is a concern of ongoing research.

So why can't we see this kind of thing in California? Well, actually we potentially could, but not for the same reasons. California does in part sit astride a divergent (or potentially divergent) boundary in a number of places. The Salton Sea and Imperial Valley area, for instance, sits in a deep trough caused by the rifting of Baja California. A few small volcanoes can be found near the lakeshore. The Basin and Range and Mojave Desert provinces in the eastern part of the state have also been rifted apart, and contain dozens of fairly recent cinder cones and lava flows. The northern Coast Ranges have a number of potentially active volcanoes in the Clear Lakes/Geysers region. And as I discussed in detail in the Other California series, the Cascades and Modoc Plateau provinces are both rich with recent volcanic activity due in part to the presence of the Cascadia subduction zone offshore to the west.

In short, our volcanoes don't erupt nearly as often as those in Iceland (39 times last century), but we do have lots of potential for future geological excitement. I would just love to see a modest eruption somewhere in the state, in one of remote spots anyway. Mt. Shasta and the Long Valley caldera are two places that I prefer would remain quiet...