Deep-Sea Trenches for Tectonics Dummies

A deep-sea trench in the Caribbean

Using a familiar word for an unfamiliar concept often creates serious problems for the common dumbass. Take, for instance, the word "trench": most people immediately think of a long, narrow ditch for burying pipes or cables. Our staff geologist, like others in his field, thinks instead of a subducting oceanic plate. It's not a straight-sided vertical hole (spade wide and shoulder deep), it's just called a "trench" because it's so long and narrow. Apparently, however, eHow.com's Mary Freeman didn't learn about trenches while picking up her "degree in human communication," which is very easy to tell from the lack of rudimentary knowledge she displays in the article "Characteristics of Deep Sea Trenches."¹

As is often the case among freelancers, Mary begins by displaying her ignorance in the first sentence:

"Deep sea trenches are formed in the space between two tectonic plates."

No, no, no, moron! Repeat after us: "There is no space between two tectonic plates!" A trench forms at a convergent margin where the rigid oceanic crust of one tectonic plate is overridden by a second plate. It isn't a "gap," a "hole" or a "space"; it's a long, narrow topographic depression. Trenches have relatively steep sides, one formed by the edge of the overriding plate and the other by the bending subducting plate. The depression forms because oceanic plates aren't carrying around enough sediment to fill in the low area.

Mary spends a lot of space describing what goes on in trenches; the flora and fauna. Most of what she says is verifiable (and reworded from material written by people who know a trench from a hole in the ground). Then she goes off the rails again: "Trenches are often formed through subduction, a process that occurs when one plate slides under another. Trenches can also be formed when tectonic plates diverge, spreading apart with a trench in the middle, or transform, moving parallel and opposite to one another."

Wrong again, Mary! Trenches form only at convergent margins. Listing the other two types of plate interactions is mere lily-gilding, just one more case of a dumbass freelancer throwing factoids at the screen to meet eHow's minimum word count. We would also like to bestow yet another Dumbass of the Day award on Demand Media Studios for putting Mary's topic in "Travel." We call that enabling...

¹ The original has been deleted by Leaf Group, but can still be accessed using the Wayback machine at archive.org. Its URL was   ehow.com/info_8588670_characteristics-deep-sea-trenches.html

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