Friday, April 18, 2014

Geo 730: April 18, Day 474: Confluence

Somewhere in the OR/WA/ID tri-state area, a spring surfaced in the Miocene. The liquid did as liquids will, and flowed downhill, rushing across the landscape. Gurgling, bubbling, and chortling across the territory later to become known as Oregon, it charged toward its confluence with the great basin of saltwater we now call the Pacific Ocean. When the torrent finally reached that shore, it playfully plunged in.

And froze solid.

Because this was no ordinary, aqueous, spring, but a vast cauldron of molten rock, likely in the range of 1200 degrees Celsius (~2200 F).

The two likely products of a basaltic lava entering water are breccia- shattered fragments- and pillows. Both are evident at Depoe Bay and in this photo. Below, I've highlighted a few of the pillows, balloon-like structures that form as lava enters the water, are quenched on the outer surface, then continue to fill for a bit.
Photo unmodified. July 10, 2012. FlashEarth location.


Hollis said...

I believe this is my favorite OstIz. The gurgling, bubbling, chortling, and playfully plunging -- only to freeze solid -- made me smile

Lockwood said...

I had four nearly identical photos of this spot, and could not figure out why. Turns out, of you enlarge it to full-size, right in the middle is a crow, who proceeded to play/bathe in the small tidepool. So all the "happy" language turns out to be even more appropriate than I had recalled. Here's a crop of another shot: