Travels in Cascadia: Walking Under the Ocean Floor at East Sooke Bay, British Columbia

We continued our explorations of British Columbia with a hike at the south end of Vancouver Island at East Sooke. It's an unusual place, out of place with the rocks that make up most of the island. The majority of Vancouver Island is made up of metamorphic rocks of the Wrangellia Terrane. These rocks originated as island arcs and continental fragments in the Pacific Ocean which added to the west coast of North America as the ocean crust sank beneath the continent at the Cascadia Subduction Zone.

Source: Chris Yorath

But the south tip of the island is made up of rocks related to the Olympic Peninsula which lies 20 miles away across the Strait of Juan de Fuca. These rocks are parts of the ocean crust, and are called the Metchosin Igneous Complex, or the Metchosin Ophiolite. They formed in Eocene time, around 50 million years ago as vast amounts of basaltic lavas spilled out on the Pacific Ocean floor

The Olympic Mountains seen from East Sooke across the Strait of Juan de Fuca

Ophiolites are generally considered to be slices of oceanic crust that form at divergent plate boundaries. The oceanic crust is pulled apart by extensional forces, relieving pressure on the underlying asthenosphere where the rocks are close to the melting point. The loss of pressure causes some melting to take place, and the resulting basaltic magma rises through fractures caused when the sea floor is pulled apart. An ophiolite has three distinct parts, with pillow basalts making up the ocean floor (more on pillows in a coming post), sheet dikes (the fractures), and gabbro plutons at the base. Gabbro is a coarse-grained igneous rock with the same composition as basalt (it cools slowly, allowing for crystal growth). A pluton is any kind of rock that has been intruded into the crust.

East Sooke Regional Park lies a few miles west of Victoria along the shoreline of the Salish Sea. For a coastal park it has an unusual 'feel'. Because the Salish Sea consists of a series of straits and inlets, wave energy is considerably diminished, at least at the times that I've been able to visit. The waves barely register and the shoreline seems more like a large lake, much like Lake Tahoe in my own home region. But the water is definitely salty!

My goal for our class this day was to get a close look at the rocks of the gabbro pluton portion of the ophiolite. In other words, we were going to go walking beneath the ocean floor. The class, a combined dyad of geology and anthropology students had other ideas. The anthropologists slightly outnumbered the geologists, so they were intent on finding some reported petroglyphs in the region. We went hiking on the Alyard Farm Trail, which was a loop of about two miles, first along the rocky shore, and ending in a thick conifer forest.

Luckily, the petroglyphs had been carved out of boulders of the gabbro, so we got the best of both worlds, with some glacial grooves as icing on the cake. Can you see the first one in the picture below? Without looking ahead, can you tell what it was meant to be (remember the landscape setting)?

I'm told that this is the representation of a sea lion. One source on the internet (the arbiter of all truth) mentions the following myth about the petroglyph: "Long years ago a great supernatural animal like a sea lion killed many of the Becher Bay Indians while they were canoeing. The tribe nearly became extinct; the remaining members were afraid to go on the water until one day a mythical man caught the sea lion and turned him into the stone representation on Alldridge Point" (Anonymous, Report of BCPM, 1928).

Note the grainy nature of the rock in the picture below. Gabbro is a dark-colored plutonic rock that has the same composition as basalt, but the individual grains are visible because of the slow rate that the magma cooled. The gray minerals are plagioclase feldspar, while the black minerals are mostly a variety of pyroxene, perhaps augite. Small grains of olivine are scattered throughout the rock.

There is a second petroglyph nearby of a salmon (below), but it has seriously faded. Both petroglyphs are attributed to the T'Sou-ke First Nation people, but the age of the rock carvings is not known. They quite likely are thousands of years old, based on the amount of weathering.

I'll probably say something similar to this many more times as we continue our exploration of British Columbia, but here we go: if you ever have the opportunity to visit Victoria and Vancouver Island, set aside some time to explore the East Sooke area. In addition to the beautiful coastal trail, there is also the East Sooke Potholes, a series of deep pools eroded out of the rocks after the last ice age. We didn't have the time to explore further up the coast, but the guides mention a number of fascinating places to investigate.

I had three main resources for the geology in and around the city of Victoria and East Sooke:
The Geology of Southern Vancouver Island by Chris Yorath
Roadside Geology of Southern British Columbia by Bill Mathews and Jim Monger
Geology of British Columbia, A Journey Through Time by Sydney Cannings, JoAnne Nelson, and Richard Cannings.

Home From Back of Beyond: Images of a Harsh Country, Part Three

This first photo may recall the disasters unfolding in the American West and Hawai'i with out-of-control wildfires and volcanic eruptions, but in this case it is no disaster. It is was the sunset on the tenth day of our recent exploration of the Colorado Plateau. We had finished our explorations of Arches and Canyonlands National Park and were headed west, towards home. It's funny, the emotions that can arise on a long journey. It felt like we were nearing the end of the trip yet we still had five days and four nights to go, and there were still four national parks on the itinerary. I've put together two previous posts of my favorite shots from the trip, and this is the third and final chapter.

We had been out for a long time, so we gave the students half a day of free time in Moab, Utah to do laundry, shower, and peruse the rock shops. But first we had one other major archaeological stop to make. The sandstone walls of the Colorado River gorge downstream of Moab contain some fascinating petroglyphs. They are cleverly hidden behind a big highway sign that says "Indian Writings".

Having signs pointing to fragile petroglyphs along a busy highway might not seem to be a good preservation strategy, but in this the highway construction itself provided the protection. There was very little space along the river for road construction, so the crews removed many tons of fallen debris to make room, the same debris the original artists stood on to chip out their art. Many of the petroglyphs are now inaccessible, fifteen or twenty feet above the roadway. One of the most unique is the bear, surrounded by hunters with bows and arrows (I think the artist was bragging).

In the afternoon we headed west and south across the barren lands around Green River. The small village is the final settlement for a hundred miles west along Interstate 70. The only settlement to the south is Hanksville, around fifty miles away. We were in one of the most isolated regions of the lower 48 states. Our destination for the night was Goblin Valley State Park on the San Rafael Swell. The sunset was glorious (the first picture of today's post was also taken there).

In Jurassic time an ocean embayment extended south from Canada into the Colorado Plateau region. Called the Sundance Sea, it left behind all manner of tidal flats, delta deposits, and coastal dunes. The Entrada Sandstone displays many of these environments, and erosion has carved the rock into a variety of fascinating shapes. For one, most of the arches of Arches National Park occur in the Entrada. At Goblin Valley, the rocks were more thinly-bedded and produced small mushroom-shaped spires that gave the valley its name. If you are a fan of sci-fi flicks, you may recognize Goblin Valley as the setting for some scenes from Galaxy Quest (the one with the little purple aliens and the rock monster).

Looking south from Goblin Valley we could see the high peaks of the Henry Mountains, often described as the last mountain range in the United States to be discovered and explored (in the 1870s). Like the La Sal Mountains described in the last post, they are laccoliths, mushroom-shaped intrusions of magma. It was at the Henry Mountains that the term laccolith was first proposed by Grove Karl Gilbert, a pioneering American geologist.

Stars. Night after night of the most starlit skies I can remember. We were in the darkest corner of the continent, and our nights for the entire trip had been free of moonlight, but the following day the thinnest crescent moon I could remember ever seeing was setting in the west. I noticed later that this first appearance of the moon on June 14 was the ending of the month of Ramadan.

Our destination the following morning was Bryce Canyon National Park. The Colorado Plateau is a remarkable region because for close to a billion years it had been remarkably stable, remaining at or close to sea level throughout Paleozoic and Mesozoic time. But in the Cenozoic this began to change as the land rose above sea level for the last time. During the early Cenozoic Era (60-40 million years ago) the region around Bryce Canyon was a huge freshwater lake. The resulting pink siltstone an limestone layer is called the Claron Formation.

The rocks of the Claron Formation are cut by vertical fractures called joints, and these fractures allow water and ice to widen the cracks and forming the spires of Bryce Canyon. The rock towers are called hoodoos. Sometimes arches and natural bridges will form during this process (natural bridges cover a watercourse while arches do not). Does anyone want to guess what kind of opening this is in the picture below? (Hint: It's named Natural Bridge)

Bryce Canyon is an exceedingly popular national park. Besides the spectacular scenery, it lies in close proximity to Zion and Grand Canyon National Parks and thus makes a "grand triangle" of a tour so beloved by bus companies and tourists on a time budget. The popularity combined with the rush that most people are in to get to the most possible localities means that certain parts of the park are more impacted than others. The free trams go to the most crowded parking lots, and the entire south end of the park tends to be far less crowded and hectic (at least in my experience). If you ever visit, make every effort to go beyond Inspiration Point and see Rainbow Point and the many other pullouts. It will take you no longer to see them than it will to wait for a parking spot to open up at the more popular viewpoints.

By the time we left Bryce that afternoon we were making serious mileage towards home. We crossed the deserts of western Utah and arrived at one of my favorite national parks of all: Great Basin. The park is not a basin, it's a mountain range, the Snake Range. It was established in 1986, although a small portion, Lehman Caves, was made a national monument in 1922. The political journey leading to the establishment of the park was different than most. As I came to understand it (and please, provide some insight in the comments if I have this wrong), there was a desire to have a national park representing the best of the Basin and Range geologic province, but promoters were split between three possible locales! There was the Toiyabe Range in central Nevada, the Ruby Range/East Humboldt Range in the northwest part of the state, and the Snake Range, which got the eventual nod. Purists supported the Toiyabe Range because it best exemplified the unique ecosystems of the Great Basin whereas the other two showed more affinities for Rocky Mountain flora. It was an interesting problem because the Ruby Mountains and Snake Range offered more "normal" mountain scenery along with glacial lakes. They really are a bit more like the Rockies. I suspect that the Snake Range got the nod because it already had the infrastructure for a national park (an extant visitor center, for instance), it had Lehman Cave as a centerpiece, but it also had Nevada's only glacier, and a forest of Bristlecone Pines, the oldest living organisms on the planet.

The park also protects Wheeler Peak (13,063 feet), which is the highest peak entirely within the boundaries of the state of Nevada (the actual high point, Boundary Peak, is a spur on the ridge of a higher peak in California, and it is only about 50 feet higher than Wheeler). There is a spectacular ridge-hugging paved road that reaches the main trailheads at over 10,000 feet.

Great Basin is one of my favorites because it still retains the character of what most national parks once were: havens of serenity and wilderness. The park is generally uncrowded (except for the lines at the visitor center for cavern tour tickets), and mostly undeveloped. There are roads and campgrounds, for instance, but many of the roads are unpaved, and the campgrounds are old style: vault toilets, and no hook-ups. The last time I checked, the campfire programs were actually done around campfires, without screens and PowerPoint presentations. I hesitate to even tell you about this because you might want to go and see it, and it will get crowded like all the rest. Just kidding, go see it. It's beautiful, and the caverns are wonderful too.

The next day was a long drive across Nevada, and we had one more night, staying at Berlin-Ichthyosaur State Park. It's a fascinating place and I would describe it in detail, but I took few pictures, and this post is all about my favorite shots from the trip (you can read some details in this post from a previous trip). The next morning we were homebound and quickly crossed the western desert hills of Nevada. We crossed Anchorite Pass and rolled into our home state of California  In a matter of minutes Mono Lake came into view. We took a break at the Interagency Visitor Center at Lee Vining.

Mono Lake is a singular ecosystem in California, like no other place in the state. It occupies a large tectonic basin, meaning it has no (current) natural outlet. Lots of water flows into the lake via streams from the adjacent Sierra Nevada, but the only way water can leave is by way of evaporation. Because of this, the salt content of the lake is three times that of seawater. Few organisms can survive such conditions, so the ecosystem is pretty straightforward: some algae, trillions of brine shrimp, trillions of brine flies, and millions of migratory and resident bird species. Mono Lake is one of the most important stops on the Pacific migratory flyway.

Unfortunately humans always find a way to muck things up, and Los Angeles worked really hard to mess up this system. It involved building a 200 mile-long aqueduct and an eleven mile-long tunnel under a series of volcanoes to siphon off water from the tributaries that drain into Mono Lake. When the city closed off the streams in 1941 Mono Lake began drying up and lost 45 feet of elevation. The salinity drastically increased, threatening to kill off the shrimp. Lawsuits dragged on for years, but now an agreement is in place to raise the lake to a sustainable level. If only the California drought would cooperate...

The day we arrived the lake was (for me) an unusual shade of turquoise. The clouds were a sight as well. There had been not a great many clouds during our trip. The lack of rain was nice, but the entire route of our trip has been in the grip of an exceptionally severe drought. We wouldn't have minded a drencher if it could have helped.

Our final national park of the trip was in some ways the most familiar, but we didn't see it from a normal angle. Something like 90% of the people who visit Yosemite National Park go to the iconic valley, but the valley makes up only 7 square miles of a 1,000 square mile park. We entered the park at Tioga Pass (9,945 feet) and drove through the alpine meadows of the upper Tuolumne River. After more than 3,000 miles of barren desert environments, the greenery was stunning. We made a final lecture stop at Olmsted Point, which provided a unique view of Half Dome, from upstream.

But that was it. Once everyone realized that we had crossed the headwaters of the river that flows through our community, there was no slowing down. Homesickness is a powerful emotion and it was almost as if our vans took on a life of their own as we rolled down the western slope of the Sierra Nevada to the end of our journey. Like crazed tourists, we had visited 10 national parks, 9 national monuments and recreation areas, and maybe a dozen state parks. We had traversed a geological history encompassing 1.7 billion years of geological events and thousands of years of human history. All it took was 15 days, 3,700 miles, and a great group of students and volunteers!

Come join us some time in the future. We're headed to the Cascades this fall with a five day trip to Mt. Shasta, Lava Beds National Monument, Lassen Volcanic National Park, and McArthur-Burney Falls State Park. Contact me for details...

Home from Back of Beyond: Images of a Harsh Country, Part Two

The photo above encompasses so much of what captivates me about the southwestern United States. A trail formed from a natural weakness in the rock providing access to an otherwise inaccessible cliff to who knows where? To be fair, hundreds of thousands of people know where the trail leads, but I like the mystery of the image. The thing is, many people DO follow this trail every year, but they may not appreciate the fact that the last time this surface was exposed to the atmosphere, it was 200 million years ago, and on the slip face of a coastal dune. Some of the irregularities highlighted by the shadows in the picture could literally be the preserved footsteps of dinosaurs, other reptiles, or amphibians.

I am slowly working on a short series of posts with my favorite images from our recently completed exploration of the Colorado Plateau and surrounding provinces. I took 1,400 photographs, so it's a bit difficult to choose between them! As we pick up the narrative, we are eight days into a fifteen day trip. As seen in an earlier post, we'd already been to the Mojave National Preserve, Zion National Park, Grand Canyon National Park, Bear's Ears National Monument, and Mesa Verde National Park. As we left Mesa Verde, we needed to find a way over the San Juan Mountains, a major range within the Rocky Mountain chain.

Because of a major wildfire in the drainage of the Animas River above Durango, we had to find another route over the mountains, so we headed instead to Lizard Head Pass (10,222 feet/3,116 meters), which divides the drainage of the Dolores and San Miguel Rivers. There was a beautiful profile of the high peaks from the summit. The brightly colored rocks above the tree line are volcanic, part of the rhyolite caldera eruptions that were taking place around 35-30 million years ago. Mineralization related to the volcanic activity resulted the emplacement of gold and silver deposits. The old mining towns like Ouray and Telluride are picturesque, but the pollution relating to the mining is a sad heritage.

Near the town of Ouray, one of the old mining camps, there is a difficult-to-see waterfall called Box Canyon Falls. The 200 foot high falls are practically hidden in a deep slot canyon, but the slopes above reveal a spectacular angular unconformity. The underlying vertical layers are more than a billion years old, but erosion planed off the rocks and in Devonian time almost 400 million years ago new sediments were draped over the older rocks. The uplift of the San Juan Mountains caused further erosion, exposing the unconformity that represents almost a billion years of missing history.

Black Canyon of the Gunnison is possibly the most bizarre canyon on the continent. It is a nearly vertical gorge that cuts through what is essentially the top of a mountain instead of having been carved through softer rocks that are exposed nearby. The Gunnison River was forced into the present channel by a series of lava flows that diverted the river from a "normal" course. Around 2-3 million years ago the landscape was uplifted, and the trapped river cut down through all the rock in its path, including the extremely hard gneiss and granite that make up the canyon walls in the park. It's not the deepest canyon in the country, but no other canyon combines the depth and steepness of Black Canyon. It is more than 2,000 feet deep in places, and in one place it is only 1,100 feet wide.

The Painted Wall (above) in Black Canyon is the highest sheer cliff in Colorado at 2,250 feet. The rocks exposed in the face of the cliff include 1.7 billion year old gneiss and schist with numerous intrusions and dikes of lighter colored granitic rock, including extremely coarse-grained pegmatite.

Late in the day we headed down one of the most spectacular roads in North America, Highway 128, which follows the Colorado River from near Interstate 70 to the outskirts of Moab, Utah. While mostly confined to a deep and narrow gorge of sandstone cliffs along the river, there is a moment when the canyon opens up and there is an awe-inspiring view of the Fisher Towers and the La Sal Mountains.

The La Sal Mountains are an anomaly in the generally horizonal landscapes of the Colorado Plateau. Between 28 and 25 million years ago, plumes of magma worked their way almost to the surface, intruding laterally between the sedimentary layers, and causing them to swell upwards like a series of blisters in the crust. The intrusions are called laccoliths. Exposed now by erosion, the igneous rocks reach elevations of almost 13,000 feet.

We arrived at our campsite in Arches National Park as the sun approached the western horizon. I don't think there is a more spectacular place in the country to roll out a sleeping bag. The view from the group camp extends for miles in every direction. There is also a beautiful arch, Skyline, visible from camp (below). The arch more than doubled in size in 1940 when a huge chunk of rock fell from the opening.

The landscapes in and around Arches and Canyonlands National Parks are almost beyond description. We spent two days in the area, and one of our stops was a rock art panel that is so delicate and fragile that I can't believe that it still exists 30 years after I first discovered it. Why? It's easily seen from the paved road leading into Canyonlands. But without signs and arrows pointing the way, people miss it. The first of the images are pictographs (below), those examples of rock art that were painted onto the sandstone. The ghostly figures and small hummingbirds are almost nightmarish in their imagery.

The other images are petroglyphs, the ones carved directly from the rocks. They depict some stylized bighorn sheep and other creatures. The panel has been somewhat damaged, possibly by natural erosion, but vandals have also done their evil work here.

Canyonlands National Park has many incredible vistas, but my favorite is the one that is framed by Mesa Arch (below). The arch is relatively small, but it frames the La Sal Mountains and pillars and cliffs of the Colorado River section of the park (the Green River forms meets the Colorado inside the park). Mesa is a popular short trail, and crowds are especially thick in the early morning when the sunrise can be photographed through the opening. You've no doubt seen an example on just about any nature-based calendar!

Pictures of Canyonlands are often mistaken for the Grand Canyon, but this section of the river includes only late Paleozoic rocks and thousands of feet of Mesozoic layers that are not seen at Grand Canyon. It is not as deep, but it is deeply colorful. It's hotter country in the summer, and there aren't many sources of water. Travel away from paved roads is more challenging than your "average" national park.

After we explored the Island in the Sky District of Canyonlands and Dead Horse Point State Park, we headed back to Arches for one of the greatest excursions on our entire trip, the hike to Delicate Arch for the sunset. The trail (a picture of which started this post) climbs 1.5 miles to an iconic overlook of the famous arch. I would love to say that the hike is an awesome desert wilderness trek where one can discover one's self in the isolation and serenity, but as author Edward Abbey feared in his 1968 book Desert Solitaire, the trail (and much of the rest of the park) has been taken over by industrial tourism. There is a large paved parking lot, and hundreds of people make the trek every evening.

Frame Arch view of Delicate Arch

The crowd at the top was rowdy, in large part because there are always selfish individuals and groups who insist on standing within the arch for selfies and group photos, spoiling the view for everyone else. I didn't have the heart to listen to the ruckus (I most certainly would have contributed, shouting at the jerks in the arch), so I headed instead to my favorite little arch in the park, Frame Arch. Frame is a small arch just above the trail only a few dozen yards from the Delicate Arch viewpoint. Most people pass it by in their race to get to more famous arch around the corner. What most of them don't realize is that Frame Arch has a great view of Delicate Arch, but also of the La Sal Mountains and Salt Wash. And I had the arch to myself for quite awhile even as hundreds of people were gathered just around the corner.

The La Sal Mountains and Salt Wash through Frame Arch

I had to think of my students though. There were a dozen of them who had hiked ahead of me, and they had to be worrying that their old overweight professor was passed out somewhere down the trail dying while they were enjoying the view. So I climbed down from the arch and back onto the trail and walked the last few yards to the overlook. I patiently waited while the jerks stood for their pictures in Delicate Arch and finally got a picture sans people as the sun settled into the horizon.

Our trip wasn't over. We had five more days and two more states to traverse. More favorite pictures soon!

Playing "Where's Waldo" with Bighorn Sheep in Zion National Park

How many Bighorn Sheep can you see in this picture?

One of the surprises of a visit to a place like Zion National Park is the possibility of seeing some of the rarer large animals. We were taking a "short cut" through the park last week on our way to the North Rim of Grand Canyon National Park. The lower valley was crowded, just as one would expect in the height of summer (not unlike Yosemite). We headed towards the much less crowded eastern entrance road when my son spotted some large animals on the ridge above, maybe two miles up the highway from the Zion Tunnel.

Would a slightly closer view help?

I stopped at the first safe pullout and walked back to try and find them. I didn't at first, but then realized they might have walked over the ridge. I walked up the road and across a rock bench and then saw them across the canyon.

Okay, I'll point to them...

They are well camouflaged. I was photographing just the two that I had spied, and then realized another three were nearby. It was a group of ewes and lambs. 

Desert Bighorn Sheep (Ovis canadensis nelsoni) were wiped out in the Zion region in the early 1900s. They were mainly done in by diseases introduced by domestic sheep who grazed the region. In 1978, 14 sheep were re-introduced to the park, and according to the National Park Service, they did poorly at first. They are doing well now, numbering around 400.

There were once millions of Bighorn Sheep across the desert southwest, so much so that they were a primary food source for the ancestral Puebloan people and other groups. 

The sheep are one of the most common motifs in the rock art (petroglyphs) found across the American West. Over the years, though, I have seen relatively few live ones. It was wonderful to see them roaming free, back in their ancestral homeland.

Where are the Ten Most Incredible Places You've Ever Stood? My Number 2: The Grandest Canyon of All

A clearing storm in Carbon Canyon, a tributary to the Grand Canyon

Of course, the Grand Canyon was going to appear on a list like this. It is one of the great spectacles of geology on planet Earth, and it has been entwined with my life many times over. I can trace the first inklings of my curiosity about geology to a vacation at the North Rim when I was a child of nine or ten. Picking up fossils in a meadow along the highway north of the park, I wondered how they could have ended up at 8,000 feet above sea level. A decade later I was a gawky thin teenager in his first year of college looking for direction in his life. A week below the rim on the New Hance and Grandview trails with an inspirational professor provided the impetus for following a career in geology. And then there has been the nearly three decades of leading students to this stunning place, introducing them to this most incredible gorge and the geological history it reveals. Yes, the Grand Canyon is one of the ten most incredible places I've ever stood.

The Desert View Watchtower on the eastern edge of the South Rim of Grand Canyon.

But there is a problem with picking the Grand Canyon as one of my "spots". It's a really big place! There are 200-plus river miles, the canyon is a mile deep and ten or fifteen miles wide, and has countless side canyons and tributaries (so many that a lot are named after their mileage along the river, i.e. Two-hundred Mile Canyon). Many of the side canyons would be national parks of their own in any other setting; Havasu Canyon and National Canyon are tens of miles long, and just as deep as the main gorge.

Mather Point, possibly. I didn't label this one!

So do you pick the rim? This is where most people see the canyon for the first time. There are two rims of course, the North and the South. Probably 90% of the park's visitors come to the South Rim, and that is where most of the facilities are located. It has some grand viewpoints, including, um, Grandview Point. I love visiting there, but it isn't the most incredible part I've stood on.

The North Rim is distinctly different. A thousand feet higher than the South Rim, it is covered with an extensive cool forest of fir and ponderosa. It's lonelier, with a single resort, a small camper store and a campground (check out the excellent Geogypsy Traveler blog for the perspectives of a North Rim ranger). No matter where I am on the North Rim, it feels more wild. It's one of my most cherished places in the world. But I can't pick out a single spot that I've stood on that set it apart from other areas of the canyon.

There are the archaeological sites. People have lived on and in the Grand Canyon for more than 4,000 years, and have left behind intriguing clues about their lives and beliefs, including the split-twig figurines and multitudes of petroglyphs and pictographs. Had I not ended up a geologist, I would most certainly have followed archaeology as a career. The Grand Canyon has some great archaeology, but I couldn't pick a single spot that represents all the canyon means to me.

It took a lot of consideration, but in the end, I knew the "spot" would have to be Hance Rapids at Mile 77 on the Colorado River. So many things in my life converged at this spot. The New Hance Trail reaches the river at this point. I walked the trail in 1976 on my first geology field studies trip and stood on the shore of the Colorado River for the first time. I had walked through 1.7 billion years of earth history to reach this spot, seeing the rocks I had been studying in class for the previous two months. The history of the canyon came alive to me as I walked in wonderment, seeing the crossbedding in sandstone caused by wind blowing over dunes 300 million years ago, the footprints of pre-dinosaurian reptiles and amphibians, the ripplemarks of long-gone rivers and beaches, and fossils from times before multicelled life existed on the planet.

It is at this point that river-runners first encounter the Granite Gorge, the Inner Canyon of the Grand Canyon. The rocks are schist and gneiss 1.7 billion years old  that formed in the roots of a long-gone mountain range that until recently was hidden in the deep crust of the lithosphere. Only in the last five or six million years has the Colorado River exposed these rocks to view. It was near this spot that John Wesley Powell wrote his immortal words about the Grand Canyon: "We are now ready to start on our way down the Great Unknown...We are three quarters of a mile in the depths of the earth...We have an unknown distance yet to run, an unknown river yet to explore. What falls there are, we know not; what rocks beset the channel, we know not; what walls rise over the river, we know not."

The Great Unconformity separates these ancient rocks from the only somewhat younger rocks of the Grand Canyon Supergroup (the reddish sediments on the right in the picture below).  The Supergroup is a group of late Proterozoic sediments that are three times as thick as the main sequence of Paleozoic rocks that make the upper 4,000 feet of the Grand Canyon cliffs. They were faulted, tilted, eroded, and ultimately buried by the advancing Cambrian sea of 515 million years ago. It may be the most famous unconformity on the planet.

This was the spot where I became a geologist.

I returned to Hance Rapids last summer for the first time in thirty years, only this time I came by raft rather than by foot. I am still processing that journey in my mind, but I already know that it was one of the most significant events in my life. I became aware of the fragile nature of life, first among the plants and animals in this challenging environment, but also of my own. Aside from the profound risk of driving a car every day, I came the closest I've ever been to realizing the possibility of death when I was dumped into the near freezing water and rode the toughest rapid for more than a quarter of a mile. We went over more than 150 rapids in seventeen days, and Hance was the first of the monster rapids, rated 8 or 9 on a scale of 10.

Some pictures surfaced a couple of years ago on my Facebook page of that first profound adventure that I had in 1976. It's remarkable how little the river and the rocks have changed, but I realized how much has changed in our understanding of how the rocks of the canyon accumulated, and how the canyon itself came into being. Plate tectonics had been accepted only a few years prior to my arrival in the canyon, and the tectonic history was only just then getting worked out. Parts of the story are still mysterious.

I also realize the massive changes in my own life since then. Back then, there was a dedicated geology professor discussing the history of the canyon, and a young man making life-changing decisions in the professor's class. The young man had not yet married, there were no children in his life, he had not earned a living on his own. He was just starting out.

Today, my kids are grown, I get awards for longevity at my job, and I'm closer to the end of my career than I am to its beginning. I am a teacher now, but I continue to be a student as well, seeking out new places, and revisiting the old ones from the past for continuing enlightenment. The canyon will continue to exist, changed only in a few ways during my tenure on the planet. It knows or cares little of the latest life form that scrabbles about its surface, and it will shrug off the gigantic reservoirs we've constructed to try and control the river.

The canyon is an incredible place. It gives us perspective in so many ways, and that's why it ended up as number two on the list of the most incredible places I've ever stood.

Just who is that thin person in the yellow jacket??