06 September, 2010

Seward Park: A Scientific Wonderland

In Seattle, you take your sunshine where and when you can get it.  The weather reports all assured me we'd get rained on Sunday, but they lied.  I decided, on a whim and on a microscopic amount of sleep, that a trip to Seward Park was in order.  I'd just found out it had glacial erratics and an earthquake scarp, hadn't I?

I ended up taking so many photos in just those few short hours that we'll have to split them into groups.  Fault scarps and erratics shall have their own special post.  In this one, we'll get an overview of some great glacial topography and some lovely sunshiny shots of life, the water, and other gorgeous things that caught my eye.

Allow me to whet your appetites with this image:

If you click to enlarge, and look to your right, you'll see sun dappling the trees in a very satisfying way.  Then follow me after the jump for more.

Seward Park occupies Bailey Peninsula, which juts out into Lake Washington like a crooked finger.  It is (drumroll please) a drumlin.  You're standing on a hill that didn't exist until the great continental ice sheets came down, covered Seattle in 3,000 feet of ice, and left their mark all over the place.  Lake Washington was created by the same glaciation.  Believe it or not, while it's huge, it's a lot more shallow than Lake Crescent - only about 200 feet at its maximum.  What it's not got in depth it makes up for in breadth - and its lovely shallows along the shore where you can see huge freshwater snail shells gathered up in tiny, quiet coves:

If I hadn't had so much astounding geology to look at and so little time before we'd lose the sunshine, I might have lingered at that grassy bank with my feet in the water.  Maybe next summer, then.

The quieter areas of Lake Washington grow a copious amount of Nymphaea odorata, the fragrant water lily, which is incredibly beautiful but decidedly non-native.  Some of them are still in bloom right now:

And yes, that's Seattle poking up in the background.  Could not, alas, find a place to get up-close and personal with the water lilies, so no macro shots of them.  Next summer, my darlings.  I know many good places where you can practically touch them.

They'd run out of maps, so I had to do a blind search for the fault scarp.  I headed up a side trail that turned out to go nowhere but right back to my car, but along the way, I saw a tree with amazingly fat roots poking up through glacial outwash:

I used to be incredibly confused by these deposits, so it's worth taking a moment to discuss them.  All over Seattle, you'll see these deposits on the tops of hills that look for all the world like a river dropped them.  There are well rounded pebbles and cobbles with the occasional odd large rock thrown in, all mixed up in a matrix of sand and clay.  And if you are ignorant of glacial landscapes, as I was, you'll ask yourself, "How the fuck could a river run through this? It's two or three hundred feet above the floodplain!"  Being from Arizona, I hadn't had much experience with such things.

Turns out all that stuff is glacial outwash.  Before the leading edge of the ice sheet got here, meltwater from it poured out up to 400 feet worth of debris.  Ice sheets 3,000 feet in thickness can do such things with ease, especially when they block local drainage to the sea and cause lakes to back up.  I'm sure it dumped plenty more on its way back to Canada, and voila - we have river and lake deposits in some very odd places indeed.  They're so thick, in fact, that you're pretty much shit out of luck if you want to see bedrock in most of the Seattle area.  But there are a few places.  Seward Park is one:

This is a chunk of very coarse sandstone fallen from one of the fault scarps.  These (I'm reasonably sure) are rocks of the Blakeley Formation, about 26-37 million years old, and they tell a story of the days when Seattle was under the sea.  The early Cascade volcanoes erupted and eroded, streams dumped the results all over the continental shelf, et voila - a few million years later, bedrock.  Volcaniclastic, in fact.  (I love that word.  Don't ask me why.)

Here's another piece, which was too pretty to pass up:

'Twas hard to tear myself away from the cliff, but blue water and bright sunshine beckoned, so I went wandering along a deserted strip of beach.  A very narrow deserted strip o' beach, which was probably why it was deserted.  And I saw one of the biggest hollow logs I've ever seen in my life, casting its reflection into the water:

How lovely is that?

Along this strip, you've got a nice bank covered in trees, blackberry brambles, and other assorted plants shielding you from the main path, and a vista of Andrews Bay:

Note the wee waves: the wind was blowing predominately from the left, but you've got waves coming in from the larger lake, too, so you get this hatched, curved pattern.  Someday, I'll know more about wave refraction and interference and all that, and I'll be able to impress people with said knowledge (glazed eyes is a sign of interest, right?)  For now, though, we'll just enjoy the lilies and the brilliant blue water and the glacial topography.

There were a bunch of purple flowers which I will someday be able to identify, all growing up through the blackberry brambles.  It's late in the season, so some of them have dropped off and developed berries.  Here we have an example of both states of being:

One of the nicest things about Andrews Bay is that you get a good view of boats against a city backdrop with a little near-wilderness thrown in.  I know my intrepid companion likes that sort o' thing, so these next two are for him since I abandoned his ass:

Regular flotilla, there.  When I came back this way as I was leaving, they had grills going and were wandering from boat-to-boat having a merry ol' time, which is just as it should be on a holiday weekend. 

This boat caught my attention because it's a bit atypical of what you normally see motoring around Lake Washington:

There are also excellent views of I90 from here.  It gleamed in the sun like a road from a sci-fi fantasy, and so of course I had to shoot it. Here it is headed into Seattle:

And to the east, crossing Mercer Island:

It looks surreal from here.  Sometimes, the things we build actually are beautiful.

Speaking of Mercer Island, here's a good view of it from near the tip of the peninsula:

I learned just recently that it's a drumlin.  Most of Seattle's fabled hills are.  Ice is an amazing artist: it dumps its materials down, then shapes and molds and reshapes and remolds, moving things here and there, piling up masses of stuff in one area whilst gouging it away from others, never quite satisfied, until it gives the whole thing up as a bad job because it's getting just too damned hot round here and melts back to happier climes.  I had only a dim idea of how powerful a sculptor it was.  Looking at Mercer Island, which gets up to 338 feet, one starts to realize that it's not just volcanoes and continental collisions that can pile up a hell of a lot of land.

It has also made it a real bitch to travel on an east-west axis in this city, lemme tell ya.

Here's another good example of the power of water to change the landscape.  The waves curve around the point and come smashing into the shore, and you can see some pretty spectacular examples of sorting:

From right to left, you can see how the wave energy changes.  As water hits the shore and slows down, it's dumped larger cobbles and angular fragments of rock.  Then there are the smaller but still large rounded bits of rock, grading into ever-smaller bits.  And you can walk the beach and tell just how strong the waves are and where they begin to lose their energy: everything's sorted into great, long and very obvious strips grading from large to small, until you round the point and get to a lot of little pebbles that tell you things on this side are fairly calm.  You can see that at a lot of beaches, but this is the best example I've found here in Seattle in a very short stretch of beach.

There's also a large grassy bank with some truly lovely blue flowers blooming in it:

Following the ever-narrowing rocky strip around the point brought me to another bank with plenty of blackberry brambles.  One of the things that's always fascinated me about Seattle is how things grow here.  In Arizona, we haven't got many blackberries, and where we do, they've bloomed, ripened, and are picked out by the end of June.  Here, they ripen late, and in areas with dappled sun, you can have new blooms with ripe berries right on top of each other:

And yes, they were incredibly tasty.  I got a wide selection from barely-ripe and delightfully tart to rich, sweet, melt-in-your-mouth goodness.  I don't care that they're invasives.  I loves me some Himalayan blackberries!

The "beach" becomes just a few inches wide a bit further along, and then you reach the end o' the line, where if you want to get round the point, it's either go back and get on the main trail, or get yourself soaked to the knee.  In that area, sheltered under an overhanging bank and a riot of plants, are some of the most extraordinary wave-carved rocks I've ever seen:

The blackberries prevented me from getting very intimate with them, so I'm not sure what that dark one with the blue base might be.  The whiter ones might be an extremely fine-grained and hard sandstone, or they might be limestone or dolomite.  I'm a bad field geologist - I didn't have hydrochloric acid or even a vial of vinegar with me, so I couldn't do the fizz test.  Never fear - next time I go to Seward Park, I'll be prepared, and the mystery shall be solved.  There's another bit of the same rock available a few feet back, out of the brambles, and it shall be duly interrogated.

Those boulders seem to be eroding out of the bank - judging from the sandy deposits in the lake bed here, I doubt the waves picked them up and moved them.  It's pretty calm just there.  But they have managed to smooth the stones wonderfully.  It's hard to see from the angles I was able to get, but those rocks have really been worked over.  They reminded me a bit of what I used to see in slot canyons.

Alas, I couldn't linger.  Had to get home to call me best friend, get food and drink, and realize how very sadly out of shape I am.  On the way back, though, I had plenty of time to linger lovingly among fault scarps, and to admire yet more blue flowers, which it turns out can grow taller than I am.  And they love to pose:

Up by the Ampitheater where I'd parked, there's a winding rock wall that begs for attention:

That's at the top of one of the fault scarps, so I imagine they put those jagged stones on the top to discourage sitting.  It's hard to see through all the plants that the ground just vanishes.  A person could step right over a cliff if they weren't paying attention.

And here are our tax dollars hard at work hanging in a tree:

Entomologist were here!  The Washington Department of Agriculture is apparently doing a study.  Science happening before our very eyes!  I wonder how many park visitors don't have a clue how important this sort of stuff is.  It makes me want to stand by random trees with green boxes in and give a quick and dirty field lesson in science.  So did the lifeguards at the beginning of the trail, who had no clue what a fault scarp is, or that they had one just a few hundred yards away.  When I retire, if the flesh is willing, I do believe I'm going to be spending the majority of my summers accosting people in parks and taking them on impromptu field trips.  This park especially is an open-air demonstration of several different branches of science all at once.  And I think people would enjoy that if they only knew.

Since you've been so good and made it to the end of the post, I'll give you a sneak preview of the fault scarp:

You know, when I first moved to Washington state, I didn't think I'd be getting much geology-wise.  A few volcanoes, yeah, and some plateau basalts, and that would be pretty much it.  When you come from a part of the country that displays in rather dramatic fashion over 1 billion years of geologic history all in one go, it's hard to believe that a place as young as Washington would have all that much.  But I've discovered some pretty damned dramatic geology up here, all the way from spreading ridges to collisions between tectonic plates, from ancient sea floors to lands left by ice sheets, and from wave-cut cliffs to cliffs made by earthquakes.  Yes, it's young land, but it hasn't had a quiet youth.  And some of the most dramatic examples of the power of mother Earth to create and destroy are right in the middle of the city.

You really can't ask for more.

For Seward Park geology, I commend this missive by Paul Talbert to your attention.  I wish every park had someone who would do up a page like this - it's outstanding.  The Friends of Seward Park do a tremendous job keeping that park in order and interesting, and you can find a lot of information on many aspects of the park at their site.  This pdf from the Geological Society of America contains quite a bit of info on the area, including bits of Seward Park. 


george.w said...

I can't wait for the new book; WALKING REALITY, using your digital camera as a tool of everyday scientific observation, by Dana Hunter

Most people take their super-sophisticated new photographic miracles and point them at people drinking beer. Which is fine, in small doses but it's all they ever do. It's wonderful how you use your camera to look more deeply.

Suzanne said...

oooooooo dana -- what a great place to get your geek on!

i wanna know what the blue rock is