Oregon Geology Parte the Third: Hug Yer Geology North

Seems like only last year I was promising you I’d get to the next installment of Oregon Geology anydaynow.  Heh heh heh whoops.  Well, better late than never, right?

For those of you just joining or wanting to refresh yourselves on the series to date, Parte the First ’tis here and Parte the Second ’tis there.  When we left off, we’d just watched the Columbia River flood basalts hit the ocean, and things had got a bit steamy.  Were this metaphor to be extended, Hug Point would have to be rated as XXX geology.  Here, basalts and sediments got really intimate.

Hug Point, viewed from Austin Point

There’s something for everyone here.  You want sedimentary rocks?  Gots ’em.  Basalts?  Yup.  Fault?  Even so!  Hydrology, check.  Coastal wave processes, oh check.  And if you’re with non-geo types, you can distract them with the pretty scenery, the nice historical wagon road to the north, and the tide pools, while you go get your rocks on.

I can’t do this place the justice it deserves.  It’s so rich geologically that an amateur like myself can merely stutter over some of its more outstanding features.  But I’ve got a ton of pretty pictures – so many, in fact, we’re going to have to split proceedings into a North Hug and a South Hug.  So come feast your eyes and feed your soul.

Two things drew me to Hug Point: the cave and the waterfall.  We’ll begin with the cave, since it’s right there to your right the instant you step off the stairs.

The Completely Awesome Hug Point Cave

This is one of the greatest wave-carved caves on the face of the earth, because it’s got a lot going on.  Let’s paint the broad outlines a bit.  The pale rocks are the sedimentary sandstones, mudstones, and conglomerate of the Astoria Formation.  The darker stuff is Grande Ronde basalt, which blundered into the Astoria on its mad dash to the sea around 15.6 million years ago.  And I do mean in to – dikes, sills, and breccia abound, basalt and sediments doing a mad little dance as they suddenly found themselves trying to occupy the same space.

Sediment vs. Basalt – Fight!

The cave shows a wonderful example of a basalt dike (or sill, I’ve seen it described both ways in my sources) intruding the Astoria Formation.  Here, it looks like the basalt squeezed its way in and made itself right at home.  Out in the weather, it’s that interesting reddish brown color.  Inside, it forms part of the roof of the cave, glistening black against the pale gold sandstone.

Basalt and Sedimentary Goodness

We’ll just have another view into the cave, then.  It’s too yummy not to:

Delicious Geologic Goodness

And yes, the cave’s big enough to stand up in.  You’d think it’s too small to get lost in, but there are ways of getting lost other than the geographic ones.  My intrepid companion very nearly didn’t manage to extract me.  There’s all too much to look at here, from the rocks stained by iron oxides:

Nature Red in Tooth and Rock

To the utterly intriguing contact between basalt and sandstone:

Contact Fascination

To the crazily contorted sediments:

Folded, Spindled and Mutilated

To the breccia:

All Broken Up

And the wave-plucked conglomerates:

Holy Conglomerate, Batman!

The back shoulder of the cave alone tells a long story:

Tilted Sediments and Conglomerate and Breccia, oh my!

The cave itself is like a geologic version of War and Peace.  If I was a little more geologically literate, I’d probably have been in there reading it until the tide came in and drowned me.  And then, just when you think you’re gonna make it round the headland, bam!  Another cave:

Ooo, Caves!

This one is a slot rather than a great gouge, but it’s awesome and it’s fun to nose into.

Rather Like a Baby Slot Canyon

Once you finally extract yourself from caves, you’re whacked in the eyeballs by some really incredible headlands:

Thar Be Hug Point!

If you have not yet divested yourself of heretics not fascinated by geology, now is the time to aim them north and babble about wagon trails that could only be traversed at low tide, and oh-did-I-mention-tide-pools-go-play-with-a-starfish-now-there’s-a-good-lad.  That should keep them occupied long enough for you to salivate in peace.

You’ll also notice another cave in the distance.  You will be tempted by it.  I assure you that, should you have had your fill of spelunking for the day, other things are going to drive that cave right out of your head.  For instance…

Mmm, Basalt!

…this enormous basalt shoulder now looming to your left.  Let us pause to admire this sill.


Here, it seems the Grande Ronde tried its damnedest to form respectable columns.  This was not an easy matter.  You know what happens to hot things when they hit cold things, and the basalt flows, still hot even after a four-hundred mile journey, had just come smack up against cool mud and cold seawater.  Had you been here, the place probably would’ve been covered in great gouts of steam.  Of course, had you been here, it’s very possible you would have gotten un-gently sauteed by hot lava, so it’s probably best you weren’t.

So, no slow and stately cooling here for the most part, and columns aren’t well-defined like they are further east where the flows could really pile up and take their time cooling down, but here we see some columnar ambitions.  And it’s so black and shiny!  Water seeps down the cliff face, making everything positively gleam.

If you stand still here, nose to rock, lovingly tracing out patterns of cracks and joints, you’ll notice you’re hearing a roar.  This is not the surf.

Fall Creek Falls

Turn around, and you shall see one of the prettiest little waterfalls in the known universe, hurtling joyfully along a NE-SW trending fault line.  Fall Creek leaps over t
he lip of Astoria Formation sandstone and goes pelting for the ocean.  You, on the other hand, probably will not.  If you’ve got any aesthetic sense at all, you’ll go sit yourself down beside the falls, right where the rush and roar of water drowns out other beachgoers’ voices, and enjoy the views.

Serenity Among the Sediments
Steams Flowing Out to Sea

As you relax there in the sun, snuggled up against warm sandstone, contemplating wave, wind and water, don’t forget to make friends with the rocks.  The sandstone’s really pretty here, full of sparkly flakes of (I’m nearly positive) mica.


Eventually, you might be able to tear yourself away and scramble up beside the falls for a good look at the fault.

Fault Line

Plenty of nice rock to poke around up there, including one that may still be in an amusing shape when you visit.

I Dub Thee Pecker Pinnacle

Random humans for scale.

The rocks up here form walls and ramparts – it’s rather like scrambling around in a natural-born castle.

Battlement Boulders

It feels like a very different world from the rough, tough basalts.  These rocks are smoother, rounded, but feel like sandpaper when you stroke them.  The basalt had actually been quite smooth and cool.  And yes, I do indeed spend my vacations petting rocks.  You of all people should understand.

Before you head back down, don’t forget to amuse yourself by gazing over the lip of the falls.

Falling off the Edge of the World – Whee!

Oh, to be a drop of water just now!

It’s about this time that you reluctantly wrest your eyes from the rocks and look up to see what the sun’s up to.  It’s hard to explore geology in the dark, after all.  And you see this great big blue thingy crashing into the rocks.

Oshit, That’s Right – There’s an Ocean…

It’s about that time you realize that the tide will be coming in soon, and you’ve got a whole south sector still needing exploring.  So, with reluctance, you tear yourself away from the great and glorious north, and begin your trek down the beach.  Which we will have to save for next time, because we’re already pushing it on pictures here.

You can see why, though, can’t you?  Told you this place was outstanding.  They may have named it Hug Point because wagoneers had to “hug” the cliffs on their travels, but a geologist might have named it that, too.  You want to hug it and squeeze it and pet it and love it and take it home with you.

Ye olde indispensable volumes of reference as the author was trying to make sense of it all:

Fires, Faults and Floods – one of the best roadside guides to the Columbia River Basin evah.

In Search of Ancient Oregon – simply the most beautiful book written about Oregon’s natural history.
Hiking Oregon’s Geology – chock full o’ adventurous goodness sure to help you get your rocks on.

Northwest Exposures – tying the whole shebang together in one easy-to-follow narrative.

Cataclysms on the Columbia – the book that truly helped me comprehend the incomprehensible.

The Restless Northwest – short, sweet, and yet comprehensive guide to Northwest geological shenanigans.

Roadside Geology of Oregon and Roadside Geology of Washington – indispensable references and inspirations.

Glacial Lake Missoula and its Humongous Floods – not only an informative guide to the discovery and history of the Floods, but an apt title, too!
Oregon Geology Parte the Third: Hug Yer Geology North

6 thoughts on “Oregon Geology Parte the Third: Hug Yer Geology North

  1. 2

    Nice!Great pics of distorted (spindled, mutilated, brecciated) seds, the contact between a dike and sandstone is interesting (no baking – is it a dike?) – and I really love the last picture of the waterfall with beach and ocean behind it!

  2. 3

    Spec-frakking-tacular! We did s trip with the OSU geology club, maybe 83, to look at these CRB-sediment interactions, but I don't recall the waterfall- which I would- so I don't think we made it to this location. Memories are hazy, but this looks better than the outcrops I remember. Gotta go see!

  3. 5

    I don't know if you receive your comments for a long time after you have made a post, but I thought I would comment anyway…This is very well written. I have been impressed with your writing ability and with your enthusiasm for it. I hope you keep up the good work, keep up the good spirit, for a long time!

  4. 6

    Super tiny sparkly bits are usually very good bets on being micas; if it's a clear shiny sparkle it's likely muscovite, and if it's a darker brown-black it's a biotite. Those are both in the mica family.Also in sandstones, tiny bits of quartz can catch the sun.Good reading. ;)

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