One Thing the Oregon / Washington Coast Have in Common with Mars

Published 03/24/22 at 12:25 AM PST
By Oregon Coast Beach Connection staff

(Astoria, Oregon) – The oddest, smallest things on the Oregon coast and Washington coast can bring much broader questions and answers. (Above: Thiel Creek near Newport)

You've likely seen them quite a bit in nature and barely given it a second thought. Then again, plenty have wondered what this particular pattern meant, and the surprising answer is that it's connected to smaller and larger things on a scale that's hard to imagine.

An Oregon Coast Beach Connection reader brought this to attention a few years back: branch-like patterns in the sands, which looked as if they were frozen. But things were well above freezing at this place in time. The patterns are easily as intricate as a tree, but the concept is fairly simple.

It's called a dendritic pattern, or more specifically in this case dendritic drainage, according to Seaside geologist Tom Horning. You'll find them in all sorts of places on the Oregon coast or Washington coast where there's streams in the sand, but you won't necessarily find them in streams on land – unless you go much higher in the air. Dendritic drainage is a phenomenon that is a microcosm for things much bigger and much smaller.

It's a pattern you'll even find on Mars where old riverbeds were. It's the one thing the Oregon and Washington coast have in common with Mars – indeed other solar system bodies where there are rivers of anything.

These shots from reader Brenda Vanderpool are from Winema Beach, a very hidden spot not far from Neskowin.

“The photo shows small tributary streams getting started in wet saturated sand,” Horning said. “The water leaks out of the sand to flow over the surface, usually soon after a wave pulls off or near a creek where ground water is in the sand. As it flows down slope, it incises a tiny channel, into which a secondary tributary channel then grows, first at the edge of the first channel and propagating up slope. If enough time allows, even a third or fourth set of tiny tributaries form. This is called a dendritic drainage formation and frequently they look like feathers or tree branches. On land, dendritic drainages can extend for miles but essentially start this way and then grow, starting a pattern that persists as long as the mountain erodes.”

Look on any map that shows outlines of rivers, or look at satellite images such as Google Earth. You'll see this same design emerge over and over, even on this grander scale.

On the tinier side, on the beaches of Oregon or Washington, they appear constantly next to streams, especially if it's been raining recently. As Horning put it, water likes to incise – or cut – its way through things. Even if it's a tiny amount of water.

In the case of the shots from Vanderpool, another little mystery arrives, but it's just a trick of light. The little dendritic lines look as if they're frozen. This is not an uncommon sight in ice.

Horning said it's just a coincidence: the photos were taken from an angle where the light is gleaming off the branch-like figures.

Then, however, some real geology kicks into gear, at least in the Thiel Creek shots from Oregon Coast Beach Connection, a place near Newport.

Horning said the darker stuff is mostly magnetite, one of the heaviest materials you'll find on the beach. Next to it are somewhat lighter materials called pyroxene. This is formed from lava. The lighter colored stuff is quartz and feldspar, some of the lightest materials you'll find on Oregon coast or Washington coast beaches.

Given that every beach has a different geology, the patterns and certainly the colors will be slightly different. Seaside is vastly different from Long Beach, which are both very different from Bandon. Around Gold Beach things get much darker, partially because there's gold flakes in the sands.

From the Viking probe / NASA: dendritic lines on Mars

The shots from near Newport show a lot of other kinds of tiny action.

One: the rock you seen in the photo has lots of holes in it because it once hosted shelled sea creatures. You'll see plenty of these around Coos Bay's Shore Acres, other parts of the south coast, Yachats or Cape Kiwanda.

Each of those materials in the sand has a different density, Horning said, and both the wind and water can push those near-microscopic materials together into different configurations or designs.

“When the sand is saturated with water it leaks out and rolls the sand grains along, and when it’s rolled it washes away, leaving the black stuff,” Horning said. “It just continues and leaves behind the greenish brown stuff, and when it cant reach any further it just stops eroding away.”

Another strange aspect of these patterns is that they're also much smaller iterations of the landslides you'll find in rivers on a much larger scale. The way grains fall away or move is not only analogous to larger riverbanks but just like that.

It's even just like other things in our solar system, except in most places out in space it's former riverbeds that have those shapes.

“It’s the same thing you find on Mars,” Horning said.

Oregon Coast Hotels in this area - South Coast Hotels - Where to eat - Maps - Virtual Tours

MORE PHOTOS BELOW

More About Oregon Coast hotels, lodging.....

More About Oregon Coast Restaurants, Dining.....

LATEST Related Oregon Coast Articles

Back to Oregon Coast

Contact Advertise on BeachConnection.net
All Content, unless otherwise attributed, copyright BeachConnection.net Unauthorized use or publication is not permitted