Back to the Variolites

Variolites, Olympic Peninsula, WA

I was back on the Elwha River again yesterday, documenting the amazing restoration project underway there after the removal of two old, salmon-proof dams.

(To learn more, go to:  http://en.wikipedia.org/wiki/Elwha_Ecosystem_Restoration)

In the meantime, however, I always had an eye out for one of my favorite rocks - the Variolite, a rare altered basalt associated with the Crescent Formation.

This is not a lapidary stone - it does not take a good polish, but it is rare and unusual enough, that I collect them whenever I see them. In France, they are considered medicinal and just quite possibly spiritual. Who knew?

Geology 101 Redux

Variolite "Cross-section" - Elwha River

One of my favorite finds from my search for variolites on Sunday was this fellow. About 6" inches long, it shows the distinctive feldspar "dots" of all variolites, but grading dramatically in size from the bottom to the top.  Varioites are believed to form inside "pillow lavas" or basaltic lava that erupts underwater, forming unmistakable round structures visible in many NW roadcuts (especially on the Olympic peninsula). My sources tell me that the smaller dots form as the edges of the pillows, which cool more quickly, while the larger dots grow in the slower-cooled, better-insulated interior of the rock.

This makes sense to me, but whatever the explanation, I thought this sample was particularly cool...

Return of the River

Variolites,  Elwha River

One of the biggest things happening in the Northwest this year has been the beginning of two dam removals from the Elwha River on the Olympic Peninsula. It is a huge project, the largest dam removal effort ever undertaken in the US and promises to restore both a spectacular river and the salmon runs that used to inhabit it.  For more information on the project, see here.

I had a chance to visit a part of the river yesterday that has re-emerged from the lake that once covered it;  gravel bars have appeared that I have never seen before!  And those gravels were covered with a rock that I have been tracking for years - Variolites (see previous posts here). I have been convinced that one major source for this rock is in the Elwha Valley. Now after finding dozens within a small area, I am convinced of it. I guess the trick will be to travel upstream until I can't find them anymore - and then look in between!

These things have no gem value, or any other reason for being sought, other than personal obsession. Stay tuned.

Mystery Rocks

Mystery Rocks, Olympic Peninsula

I would love to figure out what these rocks are. I have found them repeatedly among the beach gravels of the northern Olympic Peninsula, along the Straits of Juan de Fuca, but have not managed to figure out where they are from - or what they are.  (I found them in many locations but they are especially abundant around the mouth of the Elwha River)

They are brittle but soft enough that they do not take a polish, despite the superficial resemblance to the Orbicular Jaspers (with red spots) found in the same region.  But the raised dots are odd, and I can't think what rock type these might represent.  Anyone recognize them? The matrix is grey-green and apparently crystalline, but whatever it is, it's a really distinctive rock.

No mineral value, of course, and no one is going to make jewelery from this material, but if there is a geologist out there that recognizes it, or where it outcrops, I'd love to hear about it....

POSTSCRIPT : One reader asked whether the blebs are just surface marks, e.g. barnacle scars, but I broke some open and the spots are distributed throughout the rock.

POSTSCRIPT TWO :  MYSTERY SOLVED 8/26 !  More on a later post...