Friday, February 8, 2008

Friday Field Foto: A little volcanic geopuzzle

Since it seems to be geopuzzle day, I thought I'd pitch in with something for the more igneous-inclined. (And it's an excuse to post a cool photo - always a good thing.)


So what's going on here? Click on the image for a larger version (somehow larger than I wanted, but it'll do for now). Wild conjecture and serious exposition are equally welcome; I'm going to withhold hints for the moment, since I don't know how easy or difficult this will be for everyone. (For a sense of scale, though, I will say that the two red rocks at the top left are about 4 or 5 cm wide.)

PS - If you've been to see these, no ruining it for the guessers. I'll throw in a poster of "Volcanoes in the National Parks" for the correct answer!

14 comments:

Mel said...

I haven't seen those exact ones, but I recognized them right away from a trip I took a few years ago. Nice puzzle! I won't spoil it for others.

Callan Bentley said...

Pinecones that got caught up in a lava flow?

BrianR said...

whoa ... those are cool, whatever they are.

the individual shapes are very polygonal, like there was some contraction of some kind ... crap, I don't know my volcanic structures!

Julian said...

I have no idea what kind of scale this photo is on, but I immediately was reminded of pine cones by the shape and texture of those "inclusions."
I'm not sure exactly what kind of process it would take to preserve the pine cone structure in the midst of a lava flow, but could it be the same general principle as those lava-encrusted tree trunks in Hawaii? Or could they have been surrounded in pyroclastic stuff - a closeup in one of those Mt. St. Helens-demolished forests, perhaps?

Ron Schott said...

Okay, I honestly haven't seen these before, so I'm gonna make an educated guess. My impression (pardoning the pun) is that these maybe pineapple casts in a basaltic lava flow in Hawaii. I don't honestly recall any pineapple plantations in the areas I've visited around Kilauea, but I'm thinking maybe they're from somewhere out near the Eastern Point of the Big Island in the area of the Kapoho eruption of early 1960, which, if memory serves me erupted in a cultivated area (though I have a sneaking suspicion it wasn't pineapples). I'd think the water content of a pineapple (or similar fruit) would effectively chill the lava in much the way that tree molds are formed in the Kilauea Summit/Chain of Craters area.

Julian said...

D'oh!
I think I have to lose automatically, even if I actually got it right, for saying I had no idea of the scale despite your being sure to mention that the red rocks are 4 to 5 cm.

Tuff Cookie said...

Great guesses so far! Ron's closest with the location and the concept - these are impressions out on a lava flow near the black sand beach at Kalapana on the Big Island of Hawaii. Yep, Julian, that's the same idea as the lava trees - there 's actually a palm trunk impression a few feet away.

But they're not quite pineapples. Want to try another fruit? (Ron's got the poster, but I want to see if anyone can guess the correct agricultural product. Actually, I have lots of posters, so I'll send another to whoever gets it right.)

Callan Bentley said...

Lychees?

Callan Bentley said...

Ooh! Ooh! How about the Hala, a.k.a. Screwpine, Pandanus tectorius?

Mel said...

I'm going to have to say durians or sugar apples (Annona squamosa ). Lychee, cherimoya, alupag, and atemoya seem to small. Jackfruit seems too big.

Tuff Cookie said...

Wow...I've never even heard of some of those. Nope, keep trying. :)

Ron, if you'll send me your address using the email in the profile, I'll put your poster in the mail on Monday.

John Van Hoesen said...

Are they breadfruit casts? I first read about breadfruit in Treasure Island and was psyched to actually get to try them while in Hawaii. Nope, never been to this site either. Hopefully I'll get to visit them next year when I head over.

http://www.vanheygen.com/Silhouette/images/breadfruit.jpg

Tuff Cookie said...

Yes, indeed, they are breadfruit casts. You're a bit late to win the poster, but good guessing!

John Van Hoesen said...

No worries, I didn't even know there was a poster involved! :)

cheers
J~