OASIS comes to Barrow -- With a Yellow Submarine Pilot

[Dusty Rhodes]

Originally Posted by Floyd_Davidson

I tried to find a map on the Internet that shows a few of the things that Michelle Ridgway had on her slides to illustrate her presentation, but didn't find what I'd like. So I'll try to describe this as best that I can.

The Bering Sea is divided into two areas. Draw a diagonal line across the Bering Sea from the lower tip of the Gulf of Anadyr in Siberia, to the Pribolof Islands, and then to the Aleutian Chain at False Pass or roughly that area.

Okay, everthing north and east of that line is Beringia, a shelf that is maybe 200 meters deep (and much less in some places). But south and west of that line is a huge basin that is more than 15,000 feet (4700m) deep. But the part that was news to me was that the line between those two areas is basically a cliff, an almost shear drop off. And across that plateau flowed the Anadyr River, the Yukon River, and the Kuskwim River... and when they met the ocean in prehistoric time, when sea level was low enough that the plateau was above water land surface, these rivers flowed directly over the edge of this shelf. Today those rivers flow into the shallow part of the Bering Sea and have built a massive delta, but when flowing into deep water they dug a pair of massive canyons!

Just southwest of the Pribilof Islands, and now totally underwater, is the 8th largest submarine canyon known to exist. Pribilof Canyon is where the Kuskokwim River met the ocean.

And northwest of that is Zhemchug Canyon, the largest submarine canyon with a 2600 meter vertical relief! Apparently the Anadyr flowed into the Yukon and together they flowed into the Ocean at this one point. (Zhemchug is significantly deeper and longer than the Grand Canyon, and is multiple times farther across the top so its volume is many times that of the Grand Canyon.)

With today's technology the maximum depth a manned submarine is able to explore is about 650 meters (1950 feet). Unmanned vehicles are going down to 2000 meters. But they are still not able to come close to reaching the bottom of either Zhemchug Canyon or the Bering Sea.

The Bering Sea floor has been mapped with various technologies, and they have discovered that it has massive amounts of frozen methane gas under the bottom. That might be part of the reason it is such a productive area of ocean. Michelle has a slide showing the biomass productivity, which is dark green all the way around the edges of the deep area and also along the current that flows north through the Bering Staits into the Chukchi Sea. She said that just north of the Straits she collected a sample that turned out the be the most dense biomass sample ever found in an ocean!

Thanks Floyd,....er....Mr. Davidson, Sir!! I am pleasantly surprised that the trench exists, it is something I have suspiciously held in the corners of my brain, or what is left of it, for some time. Two Continents, that close together, to me suggested continental drift, if this were so, then one would suspect a chasm to exist, hehehehe, IT DOES!! I am tickled, every now and then one of these pet hairbrained ideas of mine turns out to be true. The Marianas are a similar phenomenon, except it is a much younger land mass, actually a collective of islands, continental drift in action, makes a snails pace look like warp 8, islands created by the volcanic activity of the earths crust being moved to the side w/trench to mark shelf differentiation (sp?), Thanks again Floyd, that bit of news will keep me grinnin' for a week!! The Alaska Range, quite young by mountain standards give rise to a lot of the colorful geological episodes found most predominately in Alaska, is still growing! And, with this growth comes the assorted earthquakes and volcanos that seem to enjoy calling Alaska," Home ". Redoubt, if you wish, but, eventually it will re-introduce itself to the populace - that's the thing when dealing with geological time, a thousand years is but a blink of an eye.

[Grannysroost]

It looked like an interesting evening...wish I could find that here...