Seafloor Spreading, the Dummies Version (Tectonics Week 1)

Aerial view of the mid-Atlantix rift passing through Iceland

Our staff geologist wanted a theme week, so we assigned him to find as many possible dumbass statements by a google search on a single word. He tried coprolite and geopetal, but quickly realized that it would take a word in semi-common use: that word turned out to be "tectonics." The first candidate he spotted for this week is eHow.com's Scott Thompson, holding forth on "What Is the Primary Force That Causes the Seafloor to Spread?"¹ at Sciencing.com. Unfortunately, Scott, par for the eHow.com course, pretty much screwed the pooch with his answer.

We know: we read that answer and referred it to the staff geologist, who told us so (note that Thompson's bio says nothing about a geology degree).

The correct answer? According to plate tectonic theory, convection currents in the mantle cause tectonic plates to move. Along divergent plate boundaries, where two plates are moving apart, new oceanic crust is created at a spreading center. So what does Scott say?  "When molten rock, or magma, rises up from far below the surface of the Earth, it can split a continental plate in two. This process is called 'rifting.'" Bzzzzzzzzt! Scott, you got that one dead wrong: the rising molten rock doesn't "split a continental plate," it  fills in the gap caused when a plate, oceanic or continental, is split by the motion of two divergent convention currents. That's what rifting is, and that's why you're the Dumbass of the Day!

¹ The original has been sent to the cleanup team by Leaf Group (we'll look at that one later), but can still be accessed using the Wayback machine at archive.org. Its URL was   ehow.com/info_8655103_primary-force-causes-seafloor-spread.html

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