Travels in Cascadia: Deserts in Canada...and What's with this Lake??

Did you know there is a desert in western Canada, in British Columbia? Well, okay not quite a desert by any standard we have down here in California and the southwestern United States, but it is a distinctly sub-arid region in a part of the continent better known for temperate rainforests. And we Californians tend to think of any place beyond the 49th parallel as an Arctic wasteland of tundra and Polar Bears. So it was a surprise as we left the alpine landscapes of Whistler and Pemberton to enter into sagebrush country and distinctly warmer weather. We were in the Okanagan Valley, on the verge of returning to the United States.

I had heard of an unusual lake to be found in the hills above the Okanagan Valley that would be a pretty handy mystery for our students, and which had a nice connection for our anthropology majors. The only problem was wondering if it would be dry or not.

Dry? Doesn't that defeat the meaning of lake? In most places, of course. But we are talking deserts here, or at least sub-arid landscapes, and yet a landscape that was sculpted by the massive continental glaciers that once covered all of Canada and 30% of the United States. Glaciers scour out all kinds of undrained depressions and blind valleys, so lakes are common. But if they don't have enough precipitation, they will dry up, and that is often the case with the lake we were seeking out that day. And as it turned out, it had been a wet year, and the lake was full of water when we arrived, and so the mystery was not quite as vivid. But there it was...

What are those weird circles in the water??

The lake has a totally different appearance in dry conditions...it's one of the strangest sights I've never seen!

Source: http://www.geologyin.com/2014/12/the-spotted-lake.html. Provenance is not clear...if this is your photo please let me know for proper attribution.

So what the heck is going on here? I will let you know below in case you want to think about it for a minute...

Source:https://tripandtravelblog.com/the-beautiful-spotted-lake-of-canada/ Provenance is not clear, if this is your photo, please let me know for proper attribution

The answer is....I don't particularly know. Well, I know some things. The lake is in an endorheic basin, and as such does not receive enough precipitation to fill the basin it occupies. Thus it dries up rather than flowing through an outlet. The drying concentrates the soluble minerals in the water. The mineral deposits are primarily magnesium sulfates (the mineral epsomite) along with calcium sulfate (gypsum), and sodium sulfate (mirabilite or thenardite). The source of the sulfates are copper minerals in the surrounding hills. Magnesium is provided by local dolomite exposures.

What I admit to not understanding is the formation of the circles and pools. The boundaries of the circles is a dark organic rich mud that develops an efflorescence of white crystals when dry. I wonder if the circles are related to periglacial processes related to frigid conditions in winter, and I would dearly love to be educated about this!

The epsomite has been mined at times a century ago, but the lake is sacred to the local indigenous First Nations people, the Okanagan Syilx. They came into ownership of the lake in 2001, and for the time being it can only be observed from the hills above on the highway, which is reasonable. One can imagine the damage that could be done by unfettered visits of ignorant tourists. The "European" name of the pond is Spotted Lake, but it has been known for centuries by the Syilx as Kliluk Lake.

Travels in Cascadia: The Toughest Hike I'll Ever Do...Stawamus Chief in British Columbia

Note that I didn't say the toughest hike YOU will ever do. Every hiking experience is individual, and this one left me...breathless. Stawamus Chief is one of the most popular hikes in the Vancouver-Squamish region of British Columbia, and when we passed through the area last July, I knew I needed to give it a shot.

Stawamus Chief is a granite dome that rises more than 2,000 feet above the east end of Howe Sound, the southernmost fjord on the west coast of North America. The dome actually has three summits, the 1st, 2nd, and 3rd, and the trail climbs to the first summit in a little over a mile. That doesn't sound so bad, does it?

The beginning of the trail is pleasingly flat, rising gently through the Stawamus Chief Campground. The wide flat trail offered no clue about what would follow. I know it sounds dramatic, but from the moment one takes the first step upward as the trail starts the climb in earnest, the trail is relentless and steep.

Some of the steps are on wood stairwells, but the rest of them are large uneven stone blocks that I found challenging. And there are no breaks. Many trails are steep, but most all of them have short breaks were the trail is level for a few steps. Not this one. It never stops climbing.

I climbed higher and higher, and grew more exhausted with each step. The thought was slowly building in my head that I was no longer young, and that some trails were simply too tough for overweight 60-somethings. But then another thought immediately followed: this quite probably was the only chance I would ever have at making the summit. Who could know if I would ever be here again, and with time marching on, my ability to climb would no doubt degrade with age. It was probably the toughest hike I would ever do (in the future sense). I decided I had to do it, and kept going. And going.

Everyone's experience will differ, of course, and some younger and healthier people would not have that much of a problem on this trail. Part of my own worries weren't so much the climb, but the descent. All of those huge steps had to be repeated, but going down, and I worried about the impact on my knees and ankles. But I had already come so far.

Stawamus Chief is a granite dome, and the resemblance to Half Dome in Yosemite Valley is unmistakable. One of the things about Half Dome is that it was never covered with glacial ice. The dome took it's iconic shape from exfoliation of the outer slabs of granite. The corners and edges snapped off as the pressure of burial was released upon exposure to the surface. Glaciers at the base quarried away the fallen rocks.

Stawamus Chief was different: as I approached the summit, a most unusual rock emerged from the trees. It was a boulder perched on a granite platform. It was a classic example of a glacial erratic, a rock left behind as the glaciers that flowed over this surface melted away. Unlike Half Dome, the summit of the Chief had been covered by glacial ice. And not just a little...the ice here was over a mile thick!

In the end, I didn't make the true summit. The young men in our group reported that another twenty minutes and 200 feet of hard climbing remained ahead. I just wasn't up to it. But I did make it to the summit ridge, which provided a stunning view of the eastern end of Howe Sound. From this elevation, the glacial origin of the fjord was obvious. And I was happy to be where I was. Elated, even. And thrilled to be alive (literally!).

The knees and ankles took the expected pounding on the way down, but no lasting damage was done. I would live another day, and take on the next challenge. It could well have been the toughest hike that I would ever do (in the future sense; I've done some really tough hikes over the years), but the neat thing about life is that you never know what comes next. Maybe I won't do this trail again, but there are many other trails and challenges ahead. Again, that sounds dramatic, but finding one's limits is always an exercise in drama.

Travels in Cascadia: You Can Have Your Niagara Falls, and I'll Have Mine...Goldstream Provincial Park, B.C.

Our journey through British Columbia last July continued. We were on Vancouver Island and were leaving the city of Victoria to catch the ferry back to the mainland at Nanaimo. But there were still some sights along the way. The town of Victoria was built on the lowlands at the south end of the island, but as we began traveling north the landscape grew more rugged and mountainous. The vast ice sheets of the last ice age covered the entire island, but the ice could not remove the tougher bedrock of the island's interior. Looking south from Malahat Summit (l,155 feet/352 meters) we could see the hills we had just explored, including the delightful Goldstream Provincial Park.

The park hosts a surprising variety of plant and animal life, due to a wide variety of habitats. Part of the value of the park is that it has not been logged, and thus preserves old-growth forests, including 700 year old Cedar trees. It includes an estuary/wetland at the end of the Finlayson Arm of the Strait of Georgia, part of the Salish Sea. The long inlet exists because the glaciers were able to exploit a fault zone that left the rocks weakened and broken. The Leech River Fault, a major terrane boundary, cuts through the park, dividing the Pacific Rim Terrane (the Leech River Complex) from Wrangellia. Wrangellia is made up of igneous intrusive rocks and metamorphic rocks from the Mesozoic Era, the age of the dinosaurs.

Looking south from the Nature Center one can see Mount Finlayson (below), another feature that indicates the presence of glaciers in the past. The rounded form of the mountain identifies it as a roche moutonnée, a larger-scale version of the rounded forms seen at Mt. Douglas and Mt. Tolmie in Victoria.

The title of today's post refers to one of the small delights of the park. The erosive action of the glaciers was oriented mostly north to south, and the ridgelines drop steeply into the valley containing the Finlayson Arm. Small creeks and rivers occasionally form modest waterfalls, including the easily accessed Niagara Falls. Visiting the waterfall, one realizes it was not named for the similarity of its volume to the better-known falls back east, but to the height. At 155 feet, it's just a bit shorter than Niagara's 167 feet (note the people at the bottom of the canyon for scale).

One might wonder why Goldstream Park has the name it has. The rocks of the Leech River Complex were altered by superheated mineralized water, and quartz veins with minor amounts of gold were emplaced in the area. The gold was discovered in 1858, and a minor rush involving perhaps 300 miners ensued a few years later. There was not a great deal of gold to be had, and the boom soon petered out, but the name remained. A few old tunnels and mines can still be seen in the park.

I know this is a geology blog, and most of the time I don't have much patience for trying to get pictures of deer, but as I was walking up the trail to the falls, I broke with tradition. Up ahead of me I could see some kind of four-footed animal, and it turned out to be the cutest little fawn ever. It was happy to share the trail with me for a few moments, until the rest of the crew caught up with me. It then took off into the underbrush.

Goldstream Provincial Park is west and north of Victoria on the Trans-Canada Highway 1. We were there on a holiday weekend and the parking lots filled quickly (we made some people very happy when our four vehicles left all at once). If you have the time and energy, a trail climbs to the summit of Mt. Finlayson.

Travels in Cascadia: Sitting Woman Falls. She's Sitting on Geological Pillows.

There are so many charming little corners to be found on Vancouver Island. We were well underway on our two-week field course on the geology and anthropology of British Columbia, and on this day we had already explored the Sooke Potholes and the base of the ocean crust at East Sooke Park (along with a couple of interesting petroglyphs). It was getting late in the afternoon and the crew was getting pretty tired, but I had heard that there was another site of interest at the end of a short trail, so we made one more stop. It was a place called Witty's Lagoon, which sounds like a theme park or something, but it actually is a geologically interesting section of coastline along the Salish Sea.

This area (and indeed all of Vancouver Island) was covered by glacial ice as recently as 13,000 years ago. When the ice melted, sea level rose to cover some of the previously exposed lands forming a series of bays and coves. Witty's Lagoon is a nice example of one of these, and it is largely unaffected by urban development. Metchosin Creek flows over a ledge of basalt to form Sitting Woman Falls at the upper end of the cove (above).

The basalt, part of what is called the Crescent Terrane, has an interesting story to tell. The basalt erupted on the floor of the Pacific Ocean around 50 million years ago at a divergent plate boundary. It originally melted because of the release of pressure at the mid-ocean ridge, and accumulated in plutons several miles beneath the ocean floor. As the crust spread apart, fractures formed and the basalt followed the breaks all the way up to the sea floor where it erupted out. When basalt erupts in water, it forms odd looking lumps about the size of old-fashioned down pillows, around two or three feet across. These pillows accumulated in layers hundreds of feet deep.

The sequence of gabbro plutons, sheet dikes (the filled fractures), and pillow basalts constitute an ophiolite sequence that in this area is called the Metchosin Igneous Complex. In our previous post we had a chance to see the gabbro as it was exposed on the shoreline of East Sooke and Becher Bay. We didn't get to see any good examples of the dikes, but the cliff at Sitting Woman Falls was composed of pillow basalts. I've zeroed in on the section of the cliff to the right of the falls in the picture above. The pillows are not really well exposed, so I've cheated by adding some pictures below of pillow basalts that we've seen elsewhere in Washington and California.

The picture above shows pillows exposed in the cliffs at Cape Disappointment at the mouth of the Columbia River in Washington. Below we can see some pillow basalts exposed near Nicasio on the Marin Headlands in California.

It's incredible to think of the forces involved in taking the oceanic crust from the bottom of the sea, and mashing it into the edge of the North American continent where it ended up being exposed at Witty's Lagoon, and indeed throughout the region, including the high peaks of the Olympic Peninsula across the Strait of Juan de Fuca.

Travels in Cascadia: Traversing the Salish Sea, and Leaving the USA

Morning in Port Angeles, looking across the Salish Sea

It was the third day of our journey through Cascadia, and after our exploration of the Olympic Peninsula, it was now time to leave the United States. We were in Port Angeles, Washington at the north end of the peninsula, and our route to Canada was by way of ferry across the Strait of Juan de Fuca. The landscape was undergoing a dramatic change. First of all we weren't in mountains anymore, we were crossing a sea. That seems an obvious point, but one has to wonder why the mountains abruptly end in a sea, and why similar mountains don't occur across the water. Second, we had reached the southern reach of the vast ice sheets that covered Canada and part of the United States during the Ice Ages that ended only around 12,000 years ago.

These two things, the end of the mountains and the end of the glaciers are related. The Strait we were crossing, along with the Strait of Georgia and the Puget Sound, are collectively known as the Salish Sea. The term was coined in the late 1980s as a way of recognizing the interconnectedness of these bodies of water as a single environmental entity. The name originated with the indigenous people who first colonized the landscape around the sea.

The Salish Sea (from http://blogs.agu.org/fromaglaciersperspective/2015/06/08/salmon-challenges-from-glaciers-to-the-salish-sea/)

The Salish Sea covers about 17,000 square kilometers (6,600 square miles), and has 7,470 kilometers (2,900 miles) of coastline, along with 419 islands. It is a unique ecosystem, a sea in the Pacific Northwest that is somewhat protected from the worst storm violence and wave action out of the Alaska region. Something like 8 million people call the shoreline home, in a megalopolis that extends from West Vancouver to Olympia. Along with people, there are 37 species of sea mammals, 172 species of birds, 247 species of fish, and over 3000 species of invertebrates.

The western margin of the Salish Sea is formed by the Olympic Peninsula and the mountains of Vancouver Island. The Strait of Juan de Fuca slices between the two landmasses. It was the strait that we were traversing on our way to the city of Victoria. 

The Olympic Peninsula is made up mostly of ocean floor sediments and basaltic rock pushed up as material was stuffed into the trench. Vancouver Island has a different origin. It is a piece of continental crust that traveled across the Pacific (at the feverish rate of a few inches per year) only to collide with the western edge of North America. Such far-traveled landmasses are called exotic terranes.

Source: http://www.deq.idaho.gov/regional-offices-issues/coeur-dalene/rathdrum-prairie-aquifer/geologic-history/

The Salish basin was shaped in large part by the ice sheets that covered essentially all of Canada and a good portion of the northern United States. As recently as 12,000 years ago, a mass of ice a mile (1.6 km) thick pushed south through the basin as far as Tacoma. A lobe of ice also extended west through what would become the Strait of Juan de Fuca.

The ferry ride took about 90 minutes to cover the 20 miles of open water between Washington and Vancouver Island. It's a beautiful ride, made all the more interesting as one realizes this entire body of water was once covered by ice. As one gets further out to sea, the higher snow-capped peaks of the Olympic Mountains come into view.

It may be that the water can get pretty choppy, especially during winter storms, but on my four trips across the strait, conditions were very calm. I almost felt like I was on a lake instead of a sea. We were still on dangerous "ground", though. The Strait of Juan de Fuca is not immune to the effects of huge earthquakes, whether in the immediate vicinity (along the Cascadia Subduction Zone), or from those at great distances (such as the 2011 Tohoku earthquake in Japan). The problem, of course, will be tsunamis.

Sometimes confined bodies of water can weaken the effect of tsunamis by dispersing the energy of the waves, but in some circumstances they can magnify the energy instead. There is some evidence of ancient tsunamis along the shorelines of some of the interior islands of the Salish Sea. The effects will probably muted compared to the damage along the Pacific Coast, but more developments are located there as well. On a positive note, the cities in the region are recognizing the threat and are talking action to minimize the damage (see an example here).

It was a beautiful cruise. Soon, we pulled into the harbor at Victoria and got ready to disembark. We were in Canada!

This post is part of a series on our field study of the geology and anthropology of British Columbia and the Pacific Northwest.

Travels in Cascadia: Burial Mounds of the Kings of the Rohirrim? The Mima Mounds of Washington

NOTE: If this post seems familiar, it should be. I posted it just a month ago. I'm re-posting (with minor changes) to place it in the proper order of the current blog series. 

One of the vivid images in my mind of the Lord of the Rings Trilogy was the resting place of the Kings of Rohan. They were buried in mounds, and the mounds were covered by the white flowers called Simbelmynë. I couldn't help think of the Kings of the Rohirrim when we arrived at the Mima Mounds Natural Area Preserve near Tumwater, Washington.

When European settlers reached the region, some of them thought that these unusual features were indeed Native American burial mounds. But when no further evidence could be found supporting the idea, they looked for other explanations. And didn't find many...

The things we don't know about our planet are, well, not known. But geologists are the first to say that the unknowns are legion. Many aspects of Earth are still a mystery. Lots of the mysteries lie hidden deep in the crust and mantle, or on the deepest parts of the ocean basins. But some mysteries are still right there in front of us, and mima mounds are one of them.

Mounded topography forms in a number of places across the central and western United States in a number of different geological environments. Although they share some similarities, it is possible that they originate from several different processes. Ideas range from the mundane to the exotic (and unlikely). Most of them occur when a fairly thin layer of soil covers a harder layer or substrate underneath. They tend to be just a few feet high, and occur in concentrations of 8-10 per acre.

The mima mounds of Washington formed at the edge of the massive ice sheet that covered most of Canada and parts of Washington as recently as 12,000 years, and so some hypotheses involve glacial meltwater, or subsurface glacial activity. Some suggest erosion of sediment from around concentrations of vegetation. More esoteric explanations involve disturbances from the vibration patterns of major earthquakes.

Occam's Razor states that among competing hypotheses, the ones that make the fewest assumptions are more likely to be correct (sometimes inaccurately described as the simplest answer is always the best). One of the more reasonable explanations for the mounds may be simply rodent activity. When pocket gophers dug into the shallow soils and encountered harder sediments, they tended to build up the mounds, and the process continued through thousands of generations. Maybe. And maybe it's aliens...

I managed to catch a photo of the mima mounds on approach to SeaTac a few years ago.

In any case, it's a fascinating place to visit. Several trails wind their way through the mounds, and there is an interpretive kiosk with a viewing platform. It is a beautiful prairie setting, with the tweeting of birds, the buzzing of insects...and an air of mystery.

I've been to the mounds in Washington twice, and the first time was in the dead of winter when no flowers were present. This time it was summer and it was a thrill to see the fields of flowers, bringing to mind the tombs of kings and the Simbelmynë.

If you want to visit the site, here are the directions from the park website:

From southbound or northbound Interstate 5, take Exit 95 and turn west on Highway 121 (Maytown Road SW) toward Littlerock. In Littlerock, continue west (forward past the school, past the intersection with Littlerock Road that curves south, and past the mini mart/gas station on the right) onto 128th Avenue. Travel about 0.8 mile where 128th Avenue ends at a 'T.' on top of the hill. Turn right onto Waddell Creek Road and travel about 1 mile. The entrance to Mima Mounds Natural Area Preserve will be on the left. A Washington State Discover Pass is required for parking at this site.

Postscript: Dustin commented when I posted the original last month, and these ideas have some merit...

Great features! My guess is that the mounds developed when glacial outflow preferentially eroded the fissures created by patterned-ground permafrost in a periglacial environment. This photo shows mounds forming from patterned ground in Alaska.

 https://en.wikipedia.org/wiki/File:Alaska_patterned_ground_1973.jpg 

In the case of the Mima mounds, if patterned ground was originally present with hard and frozen polygon centers, and margins/edges that were soft and thawed, then water flowing over the patterned ground would preferentially erode the fissures, while being less destructive to the polygon cores. Sustained flows would likely erode all evidence of patterned ground, but the Mima mounds were likely formed from ephemeral flow events associated with glacial melt near the ice sheet margins. This type of environment is suggested by the kettle lakes visible in the upper right of your airphoto, and the mounds being distributed amongst relict braided river patterns.

Travels in Cascadia: Gigantic Floods and Tallapus Meet at Willamette Falls

It's not fair, but I don't spend much time in Portland, Oregon. It's not that I don't like Portland, I just don't know it because the logistics of my normal travels rarely allow me to stop there. We are always three or four hours away from our destination and worried about getting through town without getting stopped in one of Portland's legendary traffic jams. But on our way to meet our students in Seattle for our field studies trip to British Columbia we decided to stay in Portland, ostensibly to get nice pictures of Mount Hood. We were moving along Interstate 205 and the traffic wasn't too bad, and saw a wayside viewpoint and pulled off. It was there that I discovered for the first time the work of Tallapus (Coyote) to help the Clackamas people procure a secure food supply of salmon and lamprey: Hyas Tyee Tumwater, otherwise known as Willamette Falls. It's the second largest waterfall in the United States after Niagara. It's 1,500 feet wide, drops around 40 feet, and has a flow that averages about 30,000 cubic feet per second.

What? You've never heard of it? Neither had I. I would have thought that the second largest waterfall in the country would have attracted a bit more attention among travelers, but there are reasons that it is not all that familiar. Some of the reasons go right to the heart of cultural conflicts between European colonizers and the original inhabitants of the region.

The Willamette River is a major tributary to the Columbia, providing around 10-15% of its total flow. Major rivers don't tend to have waterfalls unless unique geological conditions exist. And the story of the Willamette is pretty wild. The river is one of the few north-flowing rivers in the country, following a geologic trough related to the actions of the Cascadia Subduction Zone. In other words, the valley of the Willamette River was not carved by the Willamette River. The valley is weird in some other ways...there are fine silt layers covering much of the valley floor, but scattered here and there are hundreds of gigantic boulders weighing as much as 170 tons. Boulders that came not from the adjacent Coast or Cascades Ranges, but from Montana and Idaho! How can these things be explained?

The silt would normally be easy enough to explain. Geologists would assume that such sediments represent floodplain deposits of the Willamette, but they're not. The bedrock floor of the valley beneath the silt is actually composed of layers of basalt lava that erupted all over Washington and Oregon around 16 million years ago. The origin of the silt and the giant boulders are related one of the most incredible geologic events ever to effect Washington and Oregon. Considering the presence of giant volcanoes, gigantic rivers, and major subduction zones and earthquakes, that's saying a lot.

Between 15,000 and 13,000 years ago, the Pleistocene Ice Ages were beginning to wane, but an edge of the gigantic ice sheet that covered most of Canada flowed into Idaho and Montana and blocked of a major river drainage. A massive lake, now called Lake Missoula, formed behind the ice dam. The volume of the lake grew to 500 or 600 cubic miles of water, but then the ice dam destabilized and collapsed, sending a massive flood amounting to about ten times the combined flows of all the rivers on Earth racing across the plains of eastern Washington. The raging waters careened through the Columbia River Gorge at depths of hundreds of feet and the flows backed up into the Willamette River Valley. The muddy waters settled out, forming the silt layers covering the valley floor. The boulders arrived encased in icebergs in the turbulent currents. As the ice melted the boulders dropped out. The ice dam re-formed dozens of times and floods occurred at intervals of 50 or 60 years for around 2,000 years.

As the floodwaters receded the lava flows were exposed and then eroded by the waters draining from the Willamette. The ledges of lava became Willamette Falls.

So why isn't the second largest waterfall in the United States not a major national tourist attraction, like Niagara Falls? The basic reason is that although waterfalls are scenic and all, they are also a resource, and if humans of all cultures have anything in common, it is that if a resource is available, it will be utilized. For the Clackamas Chinook people and others in the region, the resource was food. The falls were a chokepoint on the Willamette, a barrier to the movement of salmon and lampreys upstream. Both fish could get past the falls, the salmon by jumping from one particular ledge/pool to another, and the lampreys by using their sucker mouths to climb the wet rocks. But the animals would be concentrated at the falls where they could be easily captured. The falls were considered a gift from Tallapus, and a number of villages were present in the area. The Clackamas had a surplus of salmon that they were able to trade with other tribes in the region.

Source: By M.O. Stevens - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=6816704

To American and European colonizers, the falls meant something different: power. The Native Americans had been decimated by European diseases like smallpox even before first contact, so were able to offer little resistance to the sweeping changes the colonizers brought to the waterfall. A flour mill came first in 1844, followed by paper mills beginning in 1866. A system of locks to allow upstream ship traffic was constructed in 1873. Hydroelectric generating stations arrived in 1888 and 1895. The developments destroyed the salmon runs, so a rudimentary fish ladder was blown out of the basalt in 1882. A more modern fish ladder was constructed in 1971. The flour mill was removed to make room for the paper mills, which operated until 2011. The ship locks were shut down in 2015. Only one of the power stations remains. In other words, the Willamette Falls today look like a nearly abandoned factory slum, which it technically is.

Most of these abuses are not visible from the overlook at Interstate 205. One wishes that with most of the ugly factories abandoned that the river and falls might be returned to a state resembling the primeval river. There are plans to "develop" the site with river walks and interpretive signs, but of course in the current culture of capitalism, also businesses and tourist attractions. It its own way tourism is a resource like any other, a commodity to be exploited.

In the end, I hope the stories will remain. The story of how Tallapus scooped out part of the river to slow down the migration of the salmon and lampreys so the people could catch some of them. And the story of how awesome, almost incomprehensive forces were unleashed by nature to form the falls through lava flows, glaciers, and gigantic floods.

Source: Army Corps of Engineers

Travels in Cascadia: The Southern Sentinel, Mt. Shasta

Long ago in the mists of time, the god Skell, the spirit of the Above-World descended from the heavens and alit on the summit of Mt. Shasta. Eventually Skell waged a fierce battle with the god of the Below-World, Llao, who resided in Mazama, a high mountain to the north. There was much fire and ash, and the skies grew dark. In the end Skell prevailed and the body of Llao was cast back into the underworld, taking a good portion of Mazama with him. The tears of his followers filled the gaping hole, becoming what is today known as Crater Lake.

The collapse of Mt. Mazama was an actual event around 7,000 years ago and it was witnessed and remembered by the inhabitants of the region who told the story above. Large volcanoes loom large in the consciousness of people, as they possess great power and have the potential for great destruction. Mt. Shasta is no exception, and even today a multitude of people tell stories of Lemurians, Atlanteans, and aliens who all seem to have an abode in the mountain somewhere.

Geologists are story-tellers too, although they tend not to invoke gods as a reason for the mountain's activity. They instead look for the natural laws of the Universe to understand how volcanoes work (in a sense those natural laws are the gods of the sciences). It may be that hundreds of years from now, our stories will be seen as quaint myths, but like all societies and cultures, we understand things through the prisms of our technology, mutual experiences, and observations.

I've always found it fascinating the way humans interpret their world, and I've devoted my life to teaching the scientific view. But I come from a family and a society that has not been grounded in the landscape that it inhabits. It is a society of immigrants from all over the world who invaded a "new land" that had in fact been inhabited for thousands and thousands of years before being conquered. Understanding these cultures enriches our understanding of the land, and so I find myself being enthralled by the sciences of anthropology and archaeology. Ultimately I joined forces with the professors of anthropology at Modesto Junior College to put together a series of field courses that teach both the geology and the anthropology of the landscape. We've been to Italy and Switzerland, Hawaii, and all over the Southwestern United States. Most recently though, we explored British Columbia and the northern parts of Washington state. This new series I'm writing will explain my impressions of the trip that we took with 15 students, my fellow professor of anthropology, and Mrs. Geotripper. The term "Cascadia" refers to the Cascadia subduction zone, the huge gash in the Earth's crust that dominates the geology of the region.

Our students didn't actually see Mount Shasta, unless they saw it out the plane window. They all met us at SeaTac airport, but we had reasons to drive from California to Washington. Mt. Shasta is the foremost landmark in Northern California. It is at the southern end of the Cascadia subduction zone, and is considered potentially active (Lassen Peak is even further south, but we only had a brief view of it). It is a classed as a stratovolcano (or composite cone) and is composed mostly of andesite, a gray-colored intermediate silica volcanic rock. It has had eruptions roughly every 600 years over the last 10,000 years, with the most recent event probably in 1786. At 14,179 feet, it is the second highest Cascade volcano, but in volume it is the largest. There are five major glaciers around the summit, including Whitney Glacier, which at two miles is the longest glacier in California.

The volcano is actually a composite of four different cones of different ages: Sargent's Ridge, Misery Hill, Shastina, and Hotlum Cone. There was an even earlier version of Shasta dating to 600,000 years ago, but around 300,000 years ago the summit collapsed to form a gargantuan debris slide that traveled 28 miles north of the volcano, almost to Yreka. The lumpy hummocky surface visible around the Interstate 5 rest area near Weed is part of the ancient mass wasting event.

Shasta is visible from more than a hundred miles away, but as we continued north, the mountain receded from view. We got to Portland, Oregon, just in time to catch a few sights before the sun set. That story will be in the next post!