Within weeks of signing up for a geology course during my freshman year of college, I decided to make it my major. I took to earth science for a number of reasons, not the least of which were the frequent excursions professors led from the classroom to New York State's great outdoor laboratories – Rochester's Genesee River gorge; glacial kames, drumlins and eskers; the Lake Ontario shoreline; and outcrops with textbook examples of ancient sedimentary features.
I liked the simple tools we toted – rock hammers, Brunton compasses, field notebooks, and tiny vials of acid to test for the presence of carbonate.
But I realized this week, as I walked along the twisting stream on our Indiana farm, that the language of earth science had a powerful appeal, too.
I came across a turn in the creek where hundreds of leaves had shingled against the bank, stacked there by last week's rain, and the apropos term leapt to mind – "imbricated deposits." When I'd first heard that descriptor in a course on sedimentary rocks, I'd simply liked the sound of it.
Geology is replete with words and terms that roll off the tongue, many related to ages and epochs of earth history.
"Precambrian" and "Paleozoic" are especially evocative to me (not to mention those "primordial oozes"). I like the dignity of "Devonian," the chalky bite of "cretaceous," and the springlike promise of "Eocene."
A little town just down the highway, Oolitic, Ind., derives its delightfully quirky name from a distinctive marine limestone comprised almost entirely of spherical concentric grains resembling tiny fish eggs – ooids (from the Greek oon for egg).
Although I focused my master's thesis on the microscopic textures of limestones, I also enjoyed the lingo of igneous and metamorphic geology with their "pyroclastic" and "granoblastic" textures, gabbros, obsideans, scorias, gneisses, and plutons. I admired the raw energy of terms such as tectonics and sea-floor spreading.
I enjoyed drafting my thesis far more than actually doing the research (on the Florida Keys, no less). And so, after graduation, my links to geology began to focus on writing about it for popular magazines and university reviews. I reveled in penning features on Scotland's "Moine Thrust," Anglesey's "blueschists," ancient subduction trenches, and inland seas, the evolution of angiosperms, and the rumblings of the New Madrid seismic zone in my own Midwest. Well grounded in geologic terminology, I was never at a loss for descriptions.
Now and then I carry a hammer on my walks about the farm. I'm not pretending to "do geology," but I sometimes lift the rounded concretions of geodes from the streambed and tap them open on the bank, exposing crystalline interiors of calcite and chalcedony that precipitated in darkness during the Cretaceous era.
When I think that these ancient minerals are tossing off sunlight for the first time in their 300-million-year history, words, for once, don't come.
But the language of geology remains with me, ready to leap to consciousness at any moment – when we pass a certain little town on the roads out of Bloomington and certainly when I talk to old schoolmates who have made geology their careers.
It can also happen unexpectedly, as it did when I rounded a bend in the creek and saw those perfectly imbricated deposits of water-borne leaves.