A sea of shifting sand dunes stretches before you, mile upon mile of massive mounds made of minuscule particles of silica. It is hot. You are thirsty. You are baking, you are boiling; the sand is shifting and blowing. You must walk up this dune, down this dune, up this dune, down this dune, and on and on, and the sand is soft beneath your feet… Every smallest expense of effort exhausts you; with each motion all you can say is “Erg… erg.”
And indeed there are two words erg, unrelated. One is from Greek ἔργον ergon, “work”, and is a unit of measurement in the metric system for a small amount of physical work done: a force of one dyne exerted over one centimetre – in other words, one gram centimetre-squared per second-squared, or 100 nanojoules. The other is from Arabic arq or irq or Berber irj, depending on the source you consult. It refers to one of those great seas of dunes – an area of at least 125 square kilometres where sand covers at least 20% of the surface and shifts about in the wind to make dunes. Think Lawrence of Arabia. (They have them on other planets, too, and they are an important feature on Titan, one of Saturn’s moons.) In other words, one meaning is even smaller than this three-letter, two-phoneme word, and the other is much, much larger.
It is the latter sense of this word that brought it to mind today. Verlyn Klinkenborg used it in one of his lyrical pieces for National Geographic. In the February 2012 issue, he writes of the sand on the Paria Plateau in Arizona the following:
That sand (ancient enough, grain by grain) is derived from prehistoric sand – the Navajo sandstone that forms the plateau and cliffs. This sandstone, in turn, is the remains of a vast erg, a windblown sea of dunes that for millions of years covered most of what is now the Colorado Plateau.
(A side note: Verlyn Klinkenborg is one of the great lyrical writers of nature and culture in the English language today. He also writes pieces for The New York Times and I’m not sure where else. I first encountered his work 20 years ago with his book on mid-century Buffalo, The Last Fine Time. I confess he has been a bit of an influence for me, but I do not claim to reproduce or even emulate his style.)
The shifting sands, then, may be the triturated remnants of rock of old, but it in turn can become rock. Where does the cycle begin and end? What is the chicken, what the erg? (I’m sorry. I couldn’t resist the urg. Urge, I mean.)
There is one other thing that erg makes a linguist think of: ergative. This word is derived from the Greek root mentioned above. It can refer to the sort of language wherein the subject of an intransitive is case-marked the same as the object of a transitive, but it can also refer to a particular kind of verb of which we have a goodly number in English: a verb that can be transitive or intransitive, but the subject of the intransitive is the object of the transitive. Some examples:
The sun bakes you. You bake.
The heat boils you. You boil.
The wind shifts the sand. The sand shifts.
The wind blows the sand. The sand blows.
The classic example is break, as in I break the window; the window breaks. But of course break has other senses: I break for a glass of wine. I break off.
And indeed I will break off my efforts now. I have a date with the sandman.