Oregon Coast Geology Fun Facts: Behind the Look of Cape Kiwanda

Published 12/30/2012

(Pacific City, Oregon) – It adds a whole new meaning to the idea of earthly delights.

What happened to create the Oregon coast landscapes you know and love is something just as fascinating as staring at their intricate beauty. Knowing how they got to look that way adds another dimension of enjoyment and amazement – the same way learning about fine wines can add to that experience.

At Pacific City, Cape Kiwanda and Haystack Rock have been an engaging means of repose for decades now, but its natural history goes back millions and millions of years. Here are just a few fun facts about the area.

Lots of the dunes have been around for 12,000 years or more. State of Oregon geology documents from the 70's indicate these are “extensive” around Cape Kiwanda and Sand Lake. Some of the wooded areas around Kiwanda are actually the remains of other dunes.

Geologists also say remnants of these sit just north of Netarts Bay, but that's difficult to see from aerial photographs of the area now. Perhaps these have been developed since the 70's or covered over in forest as well.

The fun and interesting fact about Cape Kiwanda is that it should've disappeared long, long ago. The colorful sandstone that makes up this dramatic and often strangely-shaped headland is extremely soft as far as rocks go and very prone to erosion. But what kept it around all these millennia is – fascinatingly enough – Haystack Rock. Made of basalt and sitting about four tenths of a mile southwest of the cape, it keeps those rough ocean waters at bay, especially during the onslaught of each winter's storm conditions. Also helping out is a formation of basalt just beneath the waves, at its southern flank.

Geologists say Cape Kiwanda actually extended all the way to Haystack Rock at one time. But the north and south faces were eroded away and finally separated it from the big rock. This caused the tip of Kiwanda to recede much faster until it reached its current position.

Above: this arch is gone now.

That erosion is continuing ever faster now, however. In fact, a sandstone arch that was at the cape's western edge, in a kind of ocean canyon formed by two chunks of the headland that had been otherwise separated, crumbled a few years back.

Photos of the area from the 1970's show dramatic differences between then and now, actually.

Sand Lake is a shallow marshland-like area, with not much public access, except at Whalen Island State Park. It's fed by a few small streams inland, but there's enough of an opening to the sea to allow a little tidal movement.

Just south of Pacific City there are some amazing geologic wonders hiding in plain sight. The famed “ghost forest” sits there – a stand of tree stumps some 2,000 years old or so. These are so named for their slightly eerie appearance, but also for the fact they are the remains of a forest caught in some sudden geologic change.

Two main theories are maintained about these. One is that something sudden and violent, like an earthquake and/or tsunami, came in and covered up the trees in sand and sediment. It's possible the ground dropped as much as 30 feet. The other theory is something less sudden, over a period of decades, when the landscape simply changed for some reason.

Whatever the exact cause, the end result was they were covered up and choked to death. But because they were immersed in sediment for at least 1,000 years, they were cloistered from the decaying effects of oxygen. They were preserved.

Proposal Rock at Neskowin is now a tree-covered island, but it's made of the same basalt that nearby Cascade Head is made of. That headland was once a volcano all its own. Proposal Rock was actually part of Cascade Head, as it was bigger at one time, according to geologists.

Pacific City is about a 20-minute drive from Lincoln City, and to the north it is about another 20-minute drive to Oceanside or Tillamook. More about Pacific City and the Three Capes Loop, including its geology. Click here for more about Oregon Coast Geology.

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