Saturday, January 24, 2015

The Sierra Beyond Yosemite: Donnell Vista and Sonora Pass

It's gloomy and foggy, and I haven't seen the sun for days. It's a few more weeks before field season (Death Valley!), but I can't help exploring the sunnier places from warmer times. I'm looking back at the pics from our fall semester where we explored a lot of places in the Sierra Nevada that aren't Yosemite.

That's the thing. Say "Sierra Nevada", and a lot of people will immediately think of the beautiful valley of the Ah-wah-nee, John Muir's favorite place on the planet, and in many ways mine as well. But the floor of Yosemite Valley is about 7 square miles. The national park covers 1,190 square miles (3,081 square kilometers). But the Sierra Nevada? It covers 39,612 sq miles (102,594 km²).  You could hide more than 30 Yosemite parks in the rest of the range. It is in fact the largest single range in the lower 48 states (large mountain systems like the Rockies and Appalachians are made up of numerous smaller sub-ranges).
So we are off onto a short exploration of some of the wonderful corners of the Sierra Nevada that aren't Yosemite Valley. We are following a week's worth of our trips last fall that took us over the range at Sonora Pass and down the east side of the range as far as Lone Pine and Mt. Whitney. We'll also explore the other national parks of the range, Sequoia and Kings Canyon, which we visited on a second trip.
We began our journey in some serious smoke from a series of fires burning through the western slopes of the Sierra Nevada. The drought and the fires have been catastrophic. We made a stop at the Twain Harte Lake exfoliation site. I wrote about it back then, and it was picked up on Reddit and IFLS, links that led to the post being the most read ever on Geotripper (12,400 hits and counting). We emerged from the smoke and climbed the upper reaches of the Stanislaus River, approaching Sonora Pass, which after Tioga is the highest paved highway over the Sierra Nevada at 9,624 feet (2,933 meters). Tioga Pass in Yosemite is 9,943 ft. (3,031 m.).

In a series of ice ages, glaciers covered about 30% of the range, reaching as low as 3,000 feet or so in some of the deeper canyons. Yosemite is simply the most famous of the glacially carved gorges, and many others are of incredible and spectacular beauty. This was not always fully appreciated, and some of these wonderful wild canyons were dammed for irrigation storage and domestic use. Hetch Hetchy is the most familiar, but the canyon below Donnell Vista on Highway 108 has also been inundated. Still, the glacial heritage of Middle Fork of the Stanislaus is evident from the viewpoint. The steep canyon walls of granitic rock and the overall U-shape of the valleys are the result first of ancient river erosion and then modification by thick rivers of ice.

If you look at the second picture above, you can see some unusual looking mountain peaks. Their blocky flat aspect indicates they are composed of something different than the "expected" granitic rock. They are the remains of lava flows, ash flows and volcanic cones that once covered this part of the Sierra Nevada. Indeed, until 9 or 10 million years ago, the Sierra looked far more like today's Cascades Range than the lofty glacial peaks we see today. There were a number of snow-covered stratovolcanoes, but much of the remainder of the range was composed of lower hills. The upper reaches of Highway 108 where it crosses Sonora Pass cut through some of the volcanic rocks.
We stopped a mile or two short of the pass to get a detailed look at the granitic rocks. Depending on the relative proportions of plagioclase and orthoclase feldspar and quartz, rocks may be identified as granite, granodiorite, tonalite, diorite, or monzonite. The rock exposed just below the pass is called the granodiorite of Topaz Lake, dated about 89 to 83 million years ago, during the Cretaceous era. It was intruded in the deep crust about 4 or 5 miles down where it cooled slowly, forming visible crystals of feldspar, quartz and dark minerals like biotite mica and hornblende.

Glaciers scoured the surface of the granodiorite, polishing it and providing a nice view of the structure of the rocks. Some of the orthoclase (potassium feldspar) has formed huge blocky crystals easily visible in the shot below. Even better, during the intrusion process, blocks of the surrounding rock broke off and sank into the magma. Composed of minerals that had higher melting points, it didn't melt, but instead persisted as an alien mass in the granitic rock. Such inclusions are called xenoliths. They provide a peek at what existed here before the intrusion of the magmas.

We drove over Sonora Pass and headed into the barren lands beyond. Our destination was the site of a gold rush, but not the one that Californians are familiar with.

Tuesday, January 20, 2015

The Insight of Werner Herzog (applied to Geology in the Field)



I was wandering through Salon.com when I ran across this piece about film director and all-around creative person Werner Herzog. Many of his excellent films have had wilderness/outdoor themes, including Grizzly Man and Encounters at the End of the World. A recent book about Herzog has a list of 24 maxims about life and film-making that really struck a chord, and I couldn't help but think how they apply to understanding not just life and film, but also geology in the field. Here, for the fun of it, is an annotated list (stuff in parentheses is mine, and not nearly so wise):

1. Always take the initiative.
2. There is nothing wrong with spending a night in jail if it means getting the shot (sample) you need.
3. Send out all your dogs (graduate students) and one might return with prey (field data that you need).
4. Never wallow in your troubles; despair must be kept private and brief.
5. Learn to live with your mistakes (so true in the field).

6. Expand your knowledge and understanding of music and literature, old and modern (the first researchers who did work in a region had much to offer).
7. That roll of unexposed celluloid you have in your hand might be the last in existence, so do something impressive with it.
8. There is never an excuse not to finish a film (field project).
9. Carry bolt cutters everywhere (!!).
10. Thwart institutional cowardice.
11. Ask for forgiveness, not permission (before you get shot for trespassing).
12. Take your fate into your own hands.
13. Learn to read the inner essence of a landscape (have you ever heard of a better explanation of field work?).

14. Ignite the fire within and explore unknown territory (the heart of the field geologist!).
15. Walk straight ahead, never detour (well, I don't know about this one...).
16. Manoeuvre and mislead, but always deliver (is this advice for teachers??).
17. Don’t be fearful of rejection (for you shall experience it much).
18. Develop your own voice.
19. Day one is the point of no return (so true in the field).
20. A badge of honor is to fail a film theory class (which geology related course should be listed here?).
21. Chance is the lifeblood of cinema (and geology in the field, too).
22. Guerrilla tactics are best.
23. Take revenge if need be.
24. Get used to the bear behind you (no further comment needed).

Thank you, Mr. Herzog for your wonderful work!

4.4 Magnitude Earthquake near Pinnacles National Park

 A 4.4 magnitude earthquake at a depth of about 10 kilometers struck Central California near Pinnacles National Park early this morning. We got an excellent seismic record of the event at Modesto Junior College, as can be seen in the picture above.

Earthquakes of this magnitude are generally felt, but are not likely to cause serious damage. The shake map generated by the U.S. Geological Survey shows that extent of the region where the quake was felt.
ShakeMap Intensity Image
The earthquake looks to have occurred on the San Andreas fault, but in detail it was more than two miles away from the fault. The movement was compressional (a "reverse" fault), rather than lateral, as would be expected on the San Andreas. The odd looking ball below is how seismologists are able to tell the type of causative fault. It is generated by the network of seismometers across Northern California, measuring whether the first wave or motion of the quake is compressional or extensional.
There is a small percent chance (5% or less) that this moderate/small event is a foreshock, or precursor earthquake to a larger event. Such moderate events are good reminders that the people who live in earthquake country must be prepared for large earthquakes. Check your emergency supplies, read up on earthquakes, and be prepared with an emergency plan for your family.

Sunday, January 18, 2015

Giant Alien Space Bear about to Destroy the Earth? Or the Impending Opening of a Great Museum?

What you are actually seeing here is the Science on a Sphere learning area in the soon-to-open Great Valley Museum, and one of the very few blank walls left in the wonderful new center of learning that will serve the northern San Joaquin Valley and the town of Modesto. The new facility was introduced to the community for the first time last night at the "Night at the Museum- the Inaugural Gala" that brought out 240 supporters to a formal dinner and tours of the museum.
The Great Valley Museum has existed since the late 1970s, occupying an old house that originally served as the Modesto Junior College campus bookstore.  The employees and volunteers did a wonderful job of bringing science education to the children of the local community, but they were always hampered by very limited facilities. There has always been a dream of a larger building, but it wasn't until our community passed Measure E in 2004 that the dream could begin to be a reality. The new Science Community Center houses the MJC Science Division with chemistry, biology, astronomy, physics and geology laboratories and classrooms upstairs. Most of the bottom floor of the huge building is now devoted to the museum. The impending opening is a thrilling moment for those of us who have planned and at times fought for a world-class facility to be housed on our campus.
Mrs. Geotripper and I had a marvelous time last night welcoming guests to the Discovery Room, the hands-on area of the museum, which also includes the live animal room. This is the "classroom" for the museum, which will be filled with an array of demonstration materials, books and science based puzzles.
We set out some of the skulls from the museum and school collections, to illustrate some exciting new discoveries that our children and students will be able to make: that our region has an incredible paleontological heritage. The first dinosaur ever discovered in California was found in our county by a 17 year old high school student in 1936. The same young man found a new species of Mosasaur just a year or so later. The skull below is a related species of the gigantic sea-going reptiles that terrorized the late Cretaceous seas. The local species ranged up to 35 feet long.
In the late Pleistocene, the savanna grasslands of our Great Valley supported an extensive ecosystem of grazing animals including horses, camels, antelope, bison, elk, and sloths. They were preyed upon by some terrifying creatures like the American Lion, the Dire Wolf, Sabertooth Cat, Grizzly Bear, and Short-faced Bears (bigger than grizzlies!). Fossils of these creatures have been found in and near our county, but to date few people are aware of this. The opening of the museum will be a big step towards filling in this missing part of our history.
It was through the efforts of our Geology Club and the late Sandy Vanwey (our division's administrative assistant and strong museum supporter) that we were able to purchase a full-scale replica skeleton of a Sabertooth Cat that will grace the entrance hallway along with a number of other symbols for the state of California.
The most important part of the museum's mission is to tell the story of the natural environments of the Great Valley, which includes the northern Sacramento Valley, and the southern San Joaquin Valley. The valley is one of the richest agricultural regions on the planet, but it also still retains some of it's primeval character in a few places, and the museum is equipped as never before to tell that story.
The museum finally has enough space to exhibit the extensive collection of preserved animals specimens in naturalistic settings.
All of the native environments of the Great Valley and adjacent foothills are represented, including grassland/prairie species, riparian species, and the animals of the wetlands and marshes.
There is only one major component of the museum left to build: the Outdoor Education Laboratory, which will be the ultimate part of the learning adventure for the children and students who visit the museum. Imagine seeing the exhibits, and then being able to go outdoors to see many of the species living in a near-natural habitat. Plans call for a stream and pond along with vegetation representing the environments that exist from the mountains to the foothills and the valley floor. The funding for this last part is still pending, but it's been a dream for everyone who has been involved in planning this facility. Proposals for an outdoor lab area date back at least 35 years. It would be such a gift to the community and science education to have that last piece fall into place in the next year or two.
In the meantime, 240 community members gathered together to support and celebrate the impending opening of the Great Valley Museum. Dozens of students and community volunteers were there to welcome them and to help out as servers and guides. It was the biggest event in the 40 year history of the museum, and it was a wonderful privilege to be involved.
The museum still needs financial support to get new teaching supplies and resources that were not provided for in the original bond act. Please consider donating! For more information, check out the museum website here, and the museum facebook page here. It's a great new day for science education on our valley, and it would be great if you could play a part!

Saturday, January 17, 2015

The Way it Was This Week: Winter in the Valley of the Ah-wah-nee


Is there a more beautiful place than this, the Ah-wah-nee, or the Yosemite as some chose to call it years ago? I'm sure that everyone who explores the outdoors has "that place", the spot that represents the highest attainment of their personal concept of beauty in nature. In my life so far, there is no place more beautiful than this.


It isn't just the scenery, which of course is spectacular. It the privilege of coming back time after time, seeing the valley and park in all seasons and all conditions. I've driven through snowstorms, rainstorms, floods, and heatwaves to reach the valley, during every month of the year. I'm guessing I've made the journey 80 or 90 times in the quarter century that I've lived in the adjacent San Joaquin Valley. I've never had a disappointing trip. There is always something new, and there are the old familiar places as well. And much more remains to be explored.
As is clear from the last couple of posts, I was in Yosemite again over the weekend, a sort of last hurrah before beginning the new semester. Despite the lack of snow in the dead of winter, it was a serenely beautiful place. And...very uncrowded. There was some kind of big athletic competition taking place last Sunday or something. The Sentinel Bridge parking area is usually packed with vehicles. Here's how it was on Sunday:

It's a rarely fulfilled desire, the dream to have the most beautiful place in the world to myself. It's just a little selfish too, but hey, I wasn't keeping anyone else from visiting that day. Most seasons it is quite hard to imagine Yosemite Valley as a wilderness. It hasn't been a wilderness for nearly two centuries. But on Sunday, here and there, it was possible to envision the wildness.

After a long dry spell, Yosemite Falls began to flow again a few weeks ago after our December storms. I hope we will have some more storms soon. After a record-setting December, January has been dry. How dry? Zilch, not a drop of rain in the San Joaquin Valley, and none in the 10 day forecast. It is a bit worrisome. Three years of record-setting drought, and this year has the makings of a fourth.

We don't usually stop at the Swinging Bridge Picnic Area, as it is usually packed with people, but not Sunday. It offered wonderful views of Upper Yosemite Falls, and one of Yosemite's less familiar peaks, North Dome (above). I'm pretty sure that if Half Dome didn't exist, or Yosemite Falls, or El Capitan, or Sentinel Rock, or Cathedral Rocks, well then, I am sure that North Dome would be one of the most famous landmarks in Yosemite Valley.
Late in the day we found ourselves in the meadow below El Capitan looking for the free-climbers as they worked their way up the cliff. The few people who were still there were looking up so intently that it took a few moments for anyone to notice that a coyote was standing among us.

I took a moment to look at the oft-ignored cliff across from El Capitan, the wall of spires between Cathedral Rocks and Sentinel Rock. The names are less familiar to most park visitors, Crocker Point, Stanford Point, Taft Fissures, and again, in any other setting, these peaks and cliffs would be the focus of a national park, rather than the relatively unknown cliffs that they are. If the panorama shot below seems a bit less sharp, it's because it was done with my smart phone rather than my usual camera.
It was a beautiful day in a beautiful place. I'm anxious to return.

Where is your most beautiful place?

Monday, January 12, 2015

If These Cliffs Could Talk: The Ah-wah-nee, To-tau-kon-nu'-la, and a Different History of the Sierra Nevada


The first question might be "what is that?". It's a pair of climbers, Kevin Jorgeson and Tommy Caldwell, on El Capitan (To-tau-kon-nu'-la) in Yosemite Valley (Ah-wah-nee) who are seeking to do something never before done...a free climb of the one of the most difficult rock faces in the world. Free climbing means they do the climb with their hands and legs only, not using artificial supports. It's not entirely insane, as they wear rope harnesses to protect them from falls, which they do a lot. In any case, their effort has made it into the national media. They haven't reached the top yet, but you can follow their saga here.
The climb up El Capitan involves about 3,000 vertical feet (914 meters). I was in Yosemite yesterday, and we reached the meadow below El Cap about sunset. Most of the spectators had already wandered off, and we wondered if we could see the climbers. It didn't take too long to find them, but needless to say, they were dwarfed by the cliff. I'm doing these pictures backwards if I'm trying to show how small they are against the cliff, but with a purpose. I realized the climbers had a slightly different story to tell, but probably not one they were intending.
In the original story told by the first people about the cliff, two bear cubs were stuck on top of the cliff and none of the animals were able to rescue them until an inchworm volunteered to climb the vertical face. It was ultimately successful, although the effort took weeks.
Geologists tell stories of the origin of the Sierra Nevada as well. Their stories are based on a different way of understanding things, and their stories are informed by data and observations, both from the Sierra Nevada, and around the world. It occurred to me that the sheer cliff of El Capitan is a metaphor that we can use to understand the immensity of geologic time.

There is nothing quite like seeing the climbers sink into insignificance against the vast expanse of vertical granite. If we imagine each foot of the rock face to represent one million years, the entire cliff face represents 3 billion years. That represents about two-thirds of the entire existence of planet Earth. So we start climbing the face as the inchworm did. There was a lot going on around the world at that time. The first kinds of life had come into existence (primitive microbes), and the first continents were starting to form from the coalescence of numerous volcanic islands. The concentration of oxygen in the atmosphere was starting to rise, albeit very slowly. But there was no vestige of the Sierra Nevada. No rocks of that age exist in California, and for that matter in pretty much the entire American West.

So we start climbing the cliff, each foot representing the passage of a million years. The oldest rocks in California, found in Death Valley and the Transverse Ranges, are 1.7 billion years old. We would find them 1,300 feet up the cliff, perhaps very close to where the climber's base camp dangles. The oldest rocks of the Sierra Nevada found in any abundance are around 500-600 million years old, meaning we would find them at the 2,400-2,500 feet above the valley floor. Keep in mind, every foot is one million years.
The oldest Sierra rocks were formed in an oceanic setting, and were pushed into the edge of the North American continent at different times between 400 and 200 million years. We've reached 2,600-2,800 feet up the cliff as we climb towards the present day. And we haven't even talked about the most common rock in the Sierra Nevada, the granitic intrusions. They happened when oceanic crust was being subducted underneath the continent. As the downward slipping slab of crust warmed up, water was liberated, changing the melting point of rocks at the base of the continental crust. The plumes of molten rock rose from the depths to within several miles of the Earth's surface. There it cooled slowly, forming the crystalline granitic rock. These events took place in episodes extending from 145 to 85 million years ago. In other words, we are now a mere 85 feet from the summit of the 3,000 foot cliff.

From 85 million to maybe 45 million years ago, miles of rock were eroded, exposing the granite at the surface. The mountain range we now call the Sierra Nevada did not yet exist in a way we would recognize. Instead, large rivers with a source in Nevada or farther out flowed westward into a sea where the Great Valley exists today. There may have been highlands, a debate continues. What we do know is that the mountains were most certainly close to their present day elevation by 2 million years ago. That is, two feet from the top of the cliff. At this time, the climate of the planet cooled, and a series of ice ages commenced. Time after time the ice advanced, melted back, advanced, and melt back yet again. This happened a dozen times or more.

About 750,000 years ago a titanic explosion rocked the Mammoth Lakes area. The eruption of the Long Valley Caldera put 150 cubic miles of ash into the atmosphere, covering the American West as far east as Kansas and Nebraska. A vast hole, twenty miles across, ten miles wide, and two miles deep, was left behind. This happened one inch from the summit on our imaginary journey. The last advance of the ice ages receded around 12,000 years ago (about a tenth of an inch from the summit). It was about this time that we have the first well-documented arrival of humans in North America. A tenth of an inch. Everything else, cultural development, wars and invasions, growth of mega-cities, all of it, happened in the infinitesimally small amount of space of the last hundredth of an inch from the summit.
I can't really say that this is the handiest or clearest way of illustrating the immensity of geologic time, but it's what occurred to me as I stared at the climbers inching their way up the cliff, much as the inchworm did many years earlier as it sought to save the bear cubs in the depths of time. The Earth has been here for a long time, and we have not. It's amazing how many changes we have caused in our brief time on this planet.

Postscript: And they've done it! The first ever free climb of the Dawn Wall ( http://www.vox.com/2015/1/14/7545571/el-capitan-climb)

Sunday, January 11, 2015

Land of Shadows and Reflections: A Winter Day at Yosemite

Yosemite is simply a magical place. No matter when one visits, something incredible is to be seen. I'm always hard put to select my favorite time of year, but usually the answer ends up along the lines of "whenever I happen to be there" (though crowded, hot, and dry August is probably my least favorite).
On a whim, Mrs. Geotripper and I decided to go visit the valley today (and believe me when I say I never take it for granted that I can go to Yosemite on a whim). After a smashing start to the water year, it's been dry for several weeks, so we weren't expecting snow and neither were we expecting to see waterfalls. Yosemite and Bridalveil falls were doing okay, but the lesser-known smaller falls like Sentinel, Ribbon and Silver Strand were dry or nearly so. But we weren't disappointed at all. The air was crisp and transparent, and the winter light brought out contrasts that are sometimes missing at other times of the year (like the smog of summer caused by hundreds of campfires).
So, today's photographs offer up some of the beauty of shadows and reflections. The first picture is of course Upper Yosemite Falls reflected in the Merced River at Swinging Bridge. We don't stop there often because most times of the year the parking lot is more than full and people are everywhere. Today it was the busiest spot we saw, but on this winter's day (with football playoffs going on) that meant maybe one or two dozen people spread out along the river and picnic area. Looking west we could see the Cathedral Rocks in shadow (the second picture). Sentinel Rock towered over us (the third shot).
A bit later we had circled the valley and stopped at Sentinel Bridge, which to my great surprise and delight had but a single car in the parking lot! We quite literally had the meadow, usually one of the single most crowded spots in Yosemite Valley, to ourselves. We spent a peaceful hour wandering the meadow and taking pictures of the Cathedral Rocks again, and reflections in the Merced River.
Many people like spring in Yosemite. The meadows are turning green, the waterfalls are booming, and the Merced River swells to fill the meadows. The dogwoods are blooming. Some people like fall the best, as the dogwood, oak, and cottonwood trees are aflame with yellow, orange, and red. Some people like summer, because that's the only chance they have to see the place, and the high country (Tuolumne Meadows and Glacier Point) is available. Winter is a special time, especially when new snowfall graces the valley floor.

But what about the dry days of winter after the snow has melted away, and all the deciduous trees are barren of leaves and the falls are barely trickling? All I can say is that of all my visits over the years, this quick excursion was one of my favorites. It isn't often that one has a place like Yosemite to one's self, and there was more than enough beauty to go around.
More pictures to come!