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.

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.

Vagabonding on Dangerous Ground: The Salish Sea and the Strait of Juan de Fuca

As we reached Port Angeles and boarded the ferry to Vancouver Island on our vagabonding journey along the Cascadia Subduction Zone, the landscape underwent a dramatic change. For one, a bunch of it was underwater, the Strait of Juan de Fuca, the Strait of Georgia, the Puget Sound, bodies of water collectively known as the Salish Sea. 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 are related.

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

The Salish 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, along with 37 species of 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, as described in the previous post, 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.

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. At least when the weather is clear! Once again, I'm resorting to pictures from 2014, as conditions were still cloudy for us on our last passage a few weeks ago.

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).

The air masses off the Pacific Ocean reach land and are forced upwards against the mountains. The water vapor condensed into clouds which billowed into huge cumulus towers that reflected off the water's surface.

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

Northern Convergence: America's Pompeii and Sailing to Canada

The first day of our journey through western Canada and the Pacific Northwest continued...

Source: Wikipedia

On this lonely beach on the far northwest corner of the Contiguous United States a village once stood. It was home to some of the Makah people who still live in the region today at Neah Bay. The village, called Ozette, was finally abandoned by the Makah in 1917 because of directives from the federal government requiring their children to attend school. The Makah had lived at the location for at least 3,800 years. Their oral history spoke of a massive landslide that destroyed an earlier town, but not much thought was given to the idea of researching the site. Archaeology in the northwest is hampered by the fact that organic material doesn't do well in the very wet and acidic conditions of the temperate rainforest. For a people who dealt mostly in wood objects, excavation seemed pointless.  A few exploratory holes were dug in 1966-67, but little of interest was found.

Source: http://americanindiantah.com/lesson_plans/ml_makah.html

In the winter of 1969-1970, severe storm erosion exposed wood planks, and archaeologists and Makah people were alerted to the presence of surprisingly well-preserved artifacts. Excavations were begun and continued for 11 years. Some 55,000 artifacts were uncovered. It was an unconventional excavation: archaeologists didn't use brushes and dental picks; they used hoses. The wood and fabric artifacts had been preserved in oxygen-free mud, and needed to be immersed in preservatives before they could dry out and decay away. The excavations eventually uncovered six longhouses dating to around 500-550 years ago. A mudflow (quite possibly a seismically induced liquefaction event) had produced America's version of Pompeii: a perfectly preserved moment in time. For the Makah people, it was a affirmation of their cultural heritage. Many of the Makah participated in the excavations, knowing they were revealing the history of their own ancestors.

The Ozette site was backfilled and little is to be seen today, but hundreds of artifacts are on display at the museum at the Makah Cultural and Research Center in Neah Bay. We took the winding road through the second-growth rainforest to see the museum, and it was worth the long drive. The exhibits are extensive, and the collaboration between the archaeologists and Makah was clearly beneficial. I could feel the pride of the people through the exploration of their past.

Source: The Makah Cultural and Research Center

After our visit, we made our way east across the northernmost part of the Olympic Peninsula on our way back to Port Angeles. Our day had started very early, but there was still a lot to see, and we needed to get to the ferry for our 9:30 voyage to Vancouver Island and Victoria. In places the forest was so thick that it formed a canopy over the highway, but at other times road hugged the coastal cliffs, offering beautiful views of the water and Vancouver Island in the distance.

Photo by Mrs. Geotripper

We saw a few Bald Eagles in the distance, but I couldn't resist including the pair we saw the previous week on the beach. They may be kind of commonplace for the folks that live in the area, but I've only seen two or three of them in our region over the years. They are regal looking birds, even if they are troublemakers at times.

The California coast near where I live is rugged and beautiful, but has very few natural harbors. Glaciation and local geological conditions have produced many harbors in the Puget Sound and Strait of Juan de Fuca. We passed tiny Sekiu. From the hill above the bay we could see Vancouver Island in the distance. The road turned inland back into Olympic National Park.

Photo by Mrs. Geotripper

We passed along the shore of Lake Crescent, a most beautiful lake with a strange geological history. It is glacial in origin, filling a hollow where the ice scooped out softer rock. It is officially listed as having a depth of 624 feet, but that was because it was the deepest their equipment could measure. It is thought to actually be more than a thousand feet deep, but no one really knows for sure. The lake once drained to the east into Indian Creek, but a gigantic landslide about 8,000 years ago split the lake (Lake Sutherland is the other part). As Lake Crescent filled deeper and deeper, the water spilled over into a different drainage, the Lyre River, which flows northwest. Isolation of lake by Lyre Falls has resulted in the evolution of two subspecies of fish, the Beardslee Trout, and the Crescenti Cutthroat Trout.

Photo by Mrs. Geotripper

Another lake along the highway was notable for not being there. The Elwha river was dammed (damned?) a hundred years ago, destroying one of the richest salmon streams on the Olympic Peninsula. A century later, it was decided that the silted-in dams were essentially useless, and their removal was begun in 2011. The lakes have been drained, and it is hoped that salmon runs can be reestablished soon.

We arrived in Port Angeles, parked in the ferry loading area and wandered into town for dinner. The promised storm had not yet arrived, and the Olympic Mountains provided a dramatic backdrop for the quiet downtown area.

The ferry left at 9:30PM meaning we got a fine view of the sun setting over the Juan de Fuca Strait.

The water was calm as we started the 90 minute, 22 mile journey across the Strait.

Most of the passengers were commuters and had obviously been on the ferry many times. They hung out in the lounges and snack bars. But not our crew. It was all "King of the World" off the bow of the ship. Luckily there were no icebergs that night.

The lights of Victoria came into view and soon afterward we dock in the beautiful harbor. We passed through immigration/customs quickly (I think it was their bedtime), drove the two miles to our hotel, checked in, and finally got to sleep. We'd made it to Canada!

Ah, the Life of the Mariner! Well, Maybe...

Ah, the open sea! The adventures of the water world of planet Earth! The mysteries of the deep! Yes, it's the mariner's life for me. Well maybe, maybe not. It's hard to develop a real opinion on the basis of a single ferry ride across the Strait of Juan de Fuca. It sure was pretty, in any case.

The Port Angeles-Victoria ferry crosses the Juan de Fuca Strait that separates the Olympic Peninsula from Vancouver Island on the the Pacific Coast between the United States and Canada. Although the peninsula and the island are both situated in the same geographic location (the western coast of North America) and are only a few miles apart, they have few similarities. The Olympic Peninsula is composed of seafloor sediment and ocean crust that has been shoved to very high elevations by the Cascadia subduction zone. Vancouver Island has a sliver of some of these rocks, but is mostly composed of metamorphic rocks of the Wrangellia Terrane, a collection of Paleozoic and Mesozoic rocks that formed someplace else, maybe thousands of miles away, and which was slammed (geologically speaking) into the west coast by subduction zone and transform fault movements.

We are out doing a bit of reconnaissance for our field studies class that meets next week. We got out to the Sooke region along the south island for a look at the Crescent terrane, and some nice erosional potholes along the Sooke River. Details to follow in later posts!

Oh, and there were lagomorphs too! Cute ones. We passed dozens of them grazing in a freeway median of all places (no, I didn't stop on the freeway for the picture; this one was at East Sooke Regional Park).

The nice thing about traveling this far north is that the sun sets late (this statement does not apply in winter, though!). We had this wonderful view of the Olympic Mountains across the Strait of Juan de Fuca around 8:30, and still had an hour of light.

I guess I'm still a landlubber though...I love the solid ground and the rocks too much.