The Other California: A Journey to the Center of the Earth (kind of...)

How many of you tried to dig a tunnel to China in the backyard when you were a kid? Given the soil conditions in the yard I grew up in, I'm probably lucky to be alive. I dug tunnels looking for buried treasures, gemstones, fossils and sometimes I was just curious what was down there. Geologists, I've found, are the kids who tried to find all those things, and never really grew up.

So how far do these overgrown kids get? It turns out that the deepest tunnels that humans have ever been able to dig reach depths of about 12,800 feet, a little over 2-1/2 miles. That might seem like a lot from our point of view, but the depth to the center of the Earth is around 4,000 miles. We've barely scratched the surface, yet the temperatures of the rock at these depths is well over 100 degrees, and the rocks are under so much pressure that explosions of rocks from the walls are a constant danger to the miners. Kids, there's got to be a better way to see what lies deep below. And there is, in the Other California, one of those places not found on the postcards. The adventure lies in the Klamath Mountains, and the most dangerous thing you have to face is slipping on a slick river rock, because geological processes have brought the rocks many miles up from the depths. You need only explore the rivers flowing off the mountains to see what the deep interior of the earth looks like.

The Klamath Mountains are a collection of bits and pieces of the earth's crust that have been carried great distances from their point of origin and slammed (at geologic speeds of inches per year) into the western edge of the North American continent. A huge variety of igneous and metamorphic rocks are found around the province, and some of the most interesting are those that once resided deep in the Earth's mantle, a layer that extends from just below the crust, from maybe 15 or 20 miles beneath our feet, to a depth of about 1,800 miles. Here are a couple of bits of the Earth's deep hidden places that I found on a short trip to the Eastern Klamath Terrane in the vicinity of Gazelle.

The oceanic crust is usually described as being made of basalt, but a few miles down in the crust the basaltic magma cools slowly to form a coarse-grained basaltic rock called gabbro. Sometimes, as can be seen above, the crystals that form are huge, with black hornblende and white feldspar crystals several inches long. Igneous rocks with such large crystals are called pegmatites.

Going even "deeper" into the interior, we pass the Mohorovicic Discontinuity, the dividing line between the crust and mantle. The upper part of the mantle is composed of olivine-rich rocks like dunite or peridotite. Olivine is best known to most people as the green gemstone peridot. That's right, much of the Earth's interior is made up of gems! The rock in the picture above is dunite, in part slightly altered to serpentine.

In many parts of the Klamath Mountains, the mantle rocks are completely altered to serpentine, the state rock of California. These ultramafic rocks are fairly rich in a number of unusual metal ores, including platinum, nickel, magnesium and mercury. One of the most important ores is chromite, which is the only significant source we have for chromium, the metal that puts the "stainless" in stainless steel. We import most of the chromium that we need from foreign sources, but in wartime (especially the two World Wars), the ores were mined domestically, and a number of operations were present in the Klamaths. The black semi-metallic crystals in the picture above are chromite, with green serpentine across the top.

In our next post we are going to "climb" into the underside of a volcano...

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...

The Other California: There's an Endemic in those Red Hills!

Oh, that's right, it's epidemics we're supposed to worry about. An endemic refers to plant species found in specific limited locations. There are a number of these in the Red Hills "Area of Critical Environmental Concern", a rather high-falutin' name for an area that less than two decades ago was barely more than an open garbage dump scarred by numerous off-road vehicle trails. The rare and endemic species are there for a very geologic reason, the subject of this post.

The Other California is my continuing blog series on those places in California that people don't generally find on the postcards at all our tourist traps. I've been following a regional theme, traveling through the northernmost provinces, but the Other California has a temporal pattern as well, and late March is the perfect time to talk about the Red Hills, located in the Sierra Nevada Mother Lode near the Gold Rush town of Chinese Camp (I talked about the area around La Grange a few days ago for the same reason).

Much of lowland California is currently covered with a green carpet of grass (mostly of exotic and invasive origin) along with the occasional oak tree, but as you can see in the pictures above, there are a few places where the grass and oak trees are missing, and a profusion of flowers and scattered pines thrive instead. Why are the oaks and grass missing?

The Mother Lode is famous as the source of the ores during the Gold Rush in 1848-53, and many people know of the association of quartz veins with the gold. What is perhaps less known is that the Mother Lode consists mostly of metamorphic rocks like slate, greenstone, and marble, not the granite that is found in the higher parts of the Sierra Nevada. These metamorphic rocks are the twisted and baked remains of sea floor muds and silts, lime from tropical reefs and shelves, and volcanic rock from the oceanic crust. These collections of crustal rocks (called "exotic terranes") were transported across the Pacific Ocean and slammed (in the geologic sense; they moved at maybe 2 inches a year) into the western edge of the North American continent, mostly in the late Paleozoic and Mesozoic eras (the Mesozoic, from around 251 to 65 million years ago, is best known as the "age of the dinosaurs"). The different terranes are separated from one another by major fault systems.

At times the crustal terranes also include rocks from beneath the crust. This rock hails from the underworld of the earth's mantle, and includes dunite and peridotite, composed primarily of the mineral olivine (known to most people as the gemstone peridot). The rock readily alters to serpentine, California's state rock. These rocks are also collectively called ultramafic rocks, for their high content of magnesium and iron (fe, the 'fi' part). They also contain small, but significant amounts of nickel and chrome.

When ultramafic rocks are brought to the surface, they are far out of chemical equilibrium with the ambient conditions, which means they are easily attacked by oxygen, water and organic acids. Clay is a common product of this process, as well as red or yellow iron oxides (from which the Red Hills take their name). The surface layer resulting from this weathering process is of course soil. We tend to think of soil as a rich surface layer that supports plant life, but some soils lack the necessary nutrients for most kinds of plant growth. This is definitely the case for soils developed on ultramafic rocks, which lack nitrates, phosphorus, and potassium. To make things worse, chrome and nickel are actually toxins. Hence, only specialized species can thrive on these rocks.

The shrubby Ceanothus, or Buckbrush (above) and Gray Pine (below) are two plants that are more or less indifferent to the odd soil conditions. They grow elsewhere, but compete very well in ultramafic soils. A large number of flower species are also indifferent to the soils, but the only grasses found in the region are native species. The European and Asian grass species that have overwhelmed most of the prairies in the Central Valley, Coast Ranges and Sierra foothills cannot grow on the serpentine soils.

There are a number of endemic species that grow on these soils, and at least one is found nowhere else in the world (California verbena, Verbena californica). Other rare endemics include Rawhide Hill onion (Allium tuolumnense), Layne's butterweed (Senecio layneae), Congdon's lomatium (Lomatium congdonii) and the Red Hills soaproot (Chlorogalum grandiflorum). A fairly common serpentine endemic is the Milkwort Jewelflower (Streptanthus polygaloides). Alas, I arrived very late in the afternoon and had no time to search them out (and to be truthful, I am better at identifying rocks and minerals).

Though closely associated with the rocks of the Mother Lode, the serpentine and dunite were remarkably free of gold, and so the Red Hills were mostly ignored by the miners. Farmers couldn't grow much in the soils, and grazing conditions were not favorable, so the when the federal government came into possession of these lands in 1848, they couldn't even give them away! So this swath of land, about 7,000 acres worth, was administered, somewhat indifferently, by the Bureau of Land Management. The landscape suffered the abuses of modern civilization, with trash heaps, motorcycle trails, and unrestrained target shooting. The recognition that the area was a unique geologic and biologic treasure led to the restriction of shooting and off-road vehicle use in 1991. Private groups assisted in cleaning up the trash heaps and a trail network was established, so today the Red Hills are a delightful place to visit, especially in the spring when the wildflowers are at their stunning best. And I could be wrong, but I don't think I've seen any postcards with pictures of the area.

If you want to learn more, or pay a visit, information about the Red Hills can be found on this BLM website , and the nature trail brochure PDF can be found here.

Don't Let Them Fall Through the Cracks! An Accretionary Wedge...

The Wedge is back! This month's new Accretionary Wedge, hosted at Geology Happens, is asking what we geologists are up to:

"Not everything I am studying ends up in a published paper, well actually nothing I study ends up in a published paper. Sometimes my HS students hear about my adventures and sometimes I write a blog post, but mostly it is just for me.

This AW is to share your latest discovery with all of us. Please let us in on your thoughts about your current work. What you are finding, what you are looking for. Any problems? Anything working out well?"

This seems a great opportunity to find out what kinds of things one can do as a geologist, and I hope lots of bloggers and readers out there are responding. As my readers must probably know by now, I teach geology at a community college. I've talked many times about the joy and motivations of being a teacher of geology (here, here, here, and very recently, here), but I don't think I've said much about the day-to-day grind.

As a professor at a community college, I wear a number of hats. Unlike many four-year universities, we are oriented more towards teaching rather than research. The school loves to tout our research if we pursue it, but it is not expected of us. Consequently, the teaching load is larger than it would be at other schools (15 hours a week of instruction time is considered full-time, plus required office hours). A teaching overload is not unusual. I teach classes in physical and historical geology, geology of California, and a distance-learning course called "Introduction to Geology". Laboratory sections are taught as part of the first two classes. Because geology is such a field-oriented science, I teach several field courses each semester, with an extended five-day trip to the Cascades, Death Valley, or the eastern Sierra Nevada, plus a number of day trips to Yosemite, the Coast Ranges, or the Sierra Nevada Mother Lode. The summer usually includes a two week exploration of the American southwest, or Pacific Northwest. If you have read my blog for any period of time, you know that taking students into the field is my favorite part of teaching.

I spend lots of time grading lab reports and tests, which I don't particularly enjoy, but responding to the student's work is one of the most important things I do; in a classroom people can hide in the back and not participate verbally, but their written work and my response is an important direct line of communication.

My job includes other responsibilities. As part of a philosophy of shared governance, we are generally expected to serve on committees, such as Academic Senate, Curriculum, Petitions, Scholarship, and so on. We participate in department and division meetings. All professors, full-time and part-time, are periodically evaluated, which includes peer review, so we spend time sitting in on other prof's courses, and providing advice and guidance. We are also involved in the hiring processes of both professors and administrators.

Finally, although it is not always spelled out in our career announcements, we are ambassadors for our school. We visit elementary school classrooms to talk to children about our work, we give presentations on geologic topics to the community (I talked about the Haiti earthquake a few months ago), and we provide expertise to local governments. I get visits all the time from people who wish an explanation of the strange rock specimens that they have discovered.

Community colleges fill many roles. We provide a bridge for high school graduates who are unsure of what path they want to follow into the future (some data suggests that our students may change majors six times or more) and we are also a cheaper alternative to high tuition universities (our transfers often do very well). We have many reentry students as well, people who need a new career after being laid off or divorced, or need to develop new skills for a changing workplace. And some students, well, they have a life-long love of learning. We are trying to make sure no one with an educational need is falling through the cracks (I had to justify the title somehow...).

So that's what I do, if you have ever wondered (no doubt all of three or four of you), but if it sounds like something you might like to do as a career, you will need to earn at least a master's degree in geology or related science. Most geology departments at California's 112 community colleges are fairly small, so full-time openings are relatively uncommon, especially in difficult budgetary times (like right now, for instance). On the other hand, the average age of us professors is, well, not so young, and many retirements can be expected in the next decade or so.

It is not very often that a newly minted college graduate scores a full-time position as a professor. Many people teach part-time at several schools for a time, or like me, work in a related capacity for a few years (I know some of my old colleagues at Santa Barbara City College occasionally look in on the blog: thanks from the bottom of my heart for the wonderful opportunity you provided me back in the 1980's!).

Teaching at a community college is a great career choice. I'll never be financially wealthy, but I have had a rich life. I have never regretted it for a moment.

Hummingbirds and Evolution

This is what jealousy looks like: my wife, not me, took this gorgeous picture of a hummingbird in our yard today among the newly blooming flowers. I had to find an excuse, however flimsy, to share it with you.

There are between 325 and 340 species of hummingbirds in the world, all in the Americas. There is almost no fossil record, which is no surprise at all, given the small size and delicate nature of their bones. Just two specimens older than Pleistocene are known, in 30 million year old rocks from Germany, which is a bit of a surprise, given their present distribution. The ancient species are modern in their appearance.

To say that the birds are highly specialized is an understatement: their energy budget must be near the limits for terrestrial animals of any sort, their flight abilities are unique to say the least (the only bird that can fly backwards), and they have unique adaptations in their overnight activities that keep them from starving overnight (basically they hibernate). I found various notes on the "Google" that suggest these birds are "proof" of intelligent design, as they are too miraculous to ever have evolved. Oh...whatever. Some sources mention that the average hummingbird is always just hours from starvation. A bird that has to consume more than its own weight in nectar every day seems to suffer from an inefficient design parameter. I dunno...I just wanted to post a pretty picture for you all!

Photo of the day by Mrs. Geotripper.

"...(they) must teach them how to get history from the ground"

"After customary greetings and handshaking, White gets down on his hands and knees with a few fossil hunters to show the tribesmen how the researchers crawl on the ground, shoulder to shoulder, to look for fossils...White explains that these stones and bones reveal the ancient history of humankind. The Alisera smile wanly, apparently amused that anyone would want to grovel on the ground for a living. They grant permission to search for fossils - for now. But they add one caveat. Someday, they say, the researchers must teach them how to get history from the ground."*

This short passage, from an article this month in Smithsonian magazine, brought to mind much of what I find so wonderful about being a teacher in the earth sciences. And a bit of frustration that I occasionally feel as well.

Human beings are curious creatures, and the earth sciences are a treasure trove of fascinating phenomena. Children are endlessly intrigued by dinosaurs, volcanoes, earthquakes, crystals and rocks. Though they try to hide it under a veneer of jaded indifference, my "grown-up" students will suddenly act like excited kids when unleashed on a slope that may reveal a fossil trilobite, a shark tooth or a gemstone. To enter the world of geology is to enter a realm of time and space where pretty much everything that could have happened did happen at some point in the past: massive volcanic eruptions, asteroid impacts, exploding stars, mass extinctions, evolution of strange and wonderful creatures of all shapes and sizes. The clues to these events lie in the grains of sand and silt, in the shapes left behind in the rock of the creatures that swam, walked or crept in numerous environments, in the trace elements found in the rocks. There are even atomic clocks in the rock that allow us to put a date to these events. I love being a teacher, I love being a story-teller. It is what makes "groveling on the ground for a living" a wonderful career. Reading of the natural curiosity of the Alisera people made me smile in recognition of the same impulses that led me into the earth sciences.

Because I realize this curiosity exists, I am patient with the visitors from the community who come to my office, explaining why the chunk of rock they found in their yard is not a dinosaur egg, or an asteroid fragment. They have come to learn something, after all. My enthusiasm dims a bit sometimes when they say "well, where can I go to find out the truth about my rock?" (it happens...), or they ask if I want to buy it anyway. But sometimes something really neat happens. A woman last year brought in what she thought was a piece of petrified wood, only to find she had a one foot section of a mammoth tusk!

But how to explain the willful and downright irrational ignorance I encounter on a too-regular basis? Well, I can't. Sometimes it is relatively harmless, but in other instances it dangerously misguided.

In the relatively harmless category we have a long discussion from Eric's Dynamic Earth about a hilariously over the top video made by an expanding earth supporter. What started as a bit of hilarity among geologists turned into a long debate with true believers, who turned out to be ignorant of some of the most basic tenets of geology. But they believe the earth is expanding, by golly, and we geologists are involved in a conspiracy of silence, preventing the truth from emerging (or expanding, as it were). For a while it was amusing to respond to the questions, but it was soon clear that the people asking the questions had no real interest in learning anything new, and especially not from people who actually understand the processes involved.

And then there are the discussions that pop up once in awhile about evolution and global climate change. The former gets into religious issues, and the latter into conservative politics. I don't want to go into details just now, but I've had a frustrating week in both areas. In short, it saddens and angers me how easily people will believe there is some kind of scientific conspiracy designed to control minds and research dollars. It makes no logical sense, but that doesn't matter. It does make sense that energy companies who stand to lose money would pay immense amounts of money to manufacture doubt. In any case, people have been told specifically what to believe by preachers with no science education, and senators or talk radio hosts with no science education. But the Jim Inhofes and Rush Limbaughs of the world do have their agendas, and the majority of us will not benefit if they are successful. Neither will our grandchildren and great-grandchildren. And how they kill a sense of wonder and understanding!

The sciences like biology, geology, and astronomy have led humanity into some of the greatest adventures of our history. We've explored the limits of outer space, and the innermost workings of the cell. We explored the vast expanse of time, the development of life, and the forces that have moved continents thousands of miles. I don't know the solution to dealing with global warming deniers or creation scientists (although I have some suggestions here). It's not easy, but it must be done.

Below, a treasure of the past, and one of the more exciting moments in one of my student's life!


* Ann Gibbons, 2010, The Human Family's Earliest Ancestors, Smithsonian, volume 40, number 12.

The Other California: The Day of the Fiddlenecks (a trip in the Mother Lode)

The Other California is my continuing exploration of the places in our state that don't tend to show up on the postcards, and are missed by most of the visitors. It's the first day of spring and we headed up into the Sierra Nevada foothills to seek out the Golden Poppy, which should be blooming explosively on the grassy slopes by now. We traveled east on Highway 132 out of Waterford towards the Gold-Rush-era town of La Grange. The poppies hadn't popped out in the lower foothill areas, but the slopes were alive with one of my favorite flowers, the Fiddleneck (Amsinckia). The shape of the flower is reminiscent of the head of a violin.

Amsinckia was utilized as a medicine and a food source by Native Americans, but the seeds and foliage are toxic to cattle. Today, for us, it was a beautiful splash of color along the slopes of the Tuolumne River, which were following out of the Central Valley.

Upstream, the first bedrock outcrops we encountered were low cliffs of rhyolitic ash of the Valley Springs formation. This gentle, quiet landscape was the scene of great violence between 22 and 28 million years ago, as huge calderas to the east exploded out vast amounts of pulverized rock and sent clouds rolling down the slopes of what would one day be the western Sierra Nevada. The rock is solid enough to form cliffs, but is easily shaped, so it was ideal for use as a building stone in the towns of the Mother Lode.

We passed through the quiet village of La Grange, looking at the 1875-vintage schoolhouse and cemetery, and a short distance east we encountered some of the evidence of gold mining (below). The sediments covering the surface were washed away to get at gold particles trapped in the small fissures and cracks in the bedrock below. Sometimes hoses were used. Downstream, where the sediments were deeper, giant dredges were used (these methods will be discussed in later posts). One of the dredges used in the area sits abandoned in a meadow just south of La Grange.

A bit east of the hydraulic pits, the old metamorphic rock of the Foothills Terrane start peeking through the soil cover. These so-called "tombstone rocks" are slate and phyllite that originated as mud and silt on the ocean floor which were accreted to the western edge of the North American continent in Mesozoic time.

Some of the rocks include metavolcanic rocks and an occasional metaconglomerate (picture below, very small penny for scale). These rocks are far more resistant to erosion, and form long high north-trending ridges in the western Mother Lode. We found a delightful new pathway over the metavolcanic ridges from Don Pedro Reservoir to the village of Moccasin along Marshes Flat Road. On this spring day, greenery was everywhere, and most of the gullies had streams flowing.

Did we find poppies? They aren't widespread just yet, but a few beautiful patches showed up along Marshes Flat road. There will be a great many more in the coming weeks. If you are in the area, make time to check it out!

For an excellent road guide to some of the areas covered in this post, and for a discussion of remediation efforts along the Tuolumne River region, check out this guide from the National Association of Geoscience Teachers and Columbia College.