Skip to main content
Worldbuilding

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

5
  • 2
    $\begingroup$ The question is about "convection currents", whatever they may be, carrying sediment 40 miles up from the bottom of the ocean to the surface. Here on Earth oceanic ecosystems sometimes rely on upwelling to get nutrients from the deep-ish ocean to the surface, but I've never heard of anything travelling up to the surface from the really deep ocean floor, with the effect being seemingly limited to a maximum of less than 1 (one) mile of vertical distance and most often no deeper than 400 meters (1/4 of a mile). $\endgroup$ Commented Feb 1 at 8:17
  • 1
    $\begingroup$ @AlexP that's why I say "if the current is energetic enough". Reportedly bomber crews saw wooden beam carried up at their cruise level by the updraft when they were flying over the firestorms they had caused upon German and Japanese cities $\endgroup$ Commented Feb 1 at 8:22
  • $\begingroup$ @AlexP, There are a few things that prevent that. The first is that we don't have 40 mile deep oceans, of course, but also we have thermoclines that prevent a lot of mixing. What we don't have is a lot of volcanic activity in the deep ocean. Our oceans are shallow enough that most volcanic activity will create an island. With an ocean that's deeper than our tallest mountains, even the tallest continental plate would be submerged. That leaves plenty of opportunity for volcanic upwelling. $\endgroup$ Commented Feb 1 at 22:08
  • $\begingroup$ @RobertRapplean: Earth has a lot of submarine volcanoes; three quarters of the magma output on Earth come from submarine volcanoes. And we have a lot of ocean deeper than 1 mile, and yet no upwelling was ever observed carrying to the surface nutrients from more than 1 mile down, and even that is very exceptional. (The average depth of Earth's oceans is about 3,700 meters or 2.3 miles.) $\endgroup$ Commented Feb 1 at 22:45
  • 1
    $\begingroup$ @AlexP, I checked a few extra sources and concede the point. Volcanic heating doesn't make the water rise more than a kilometer, but does spread out a lot after that. The high pressure prevents density-based rising, keeping even super-critical water from expanding the way gasses do. That really surprised me. By the time it hits a kilometer, enough mixing has happened to even out the density. $\endgroup$ Commented Feb 2 at 0:18