A NUANCED VIEW
nuance |ˈn(y)o͞oˌäns| nouna subtle difference in or shade of meaning, expression, or sound: the nuances of facial expression and body language.
It is an easy thing for many of our friends and members to visualize the geology of the Greater Yellowstone Region. We have a mental picture, in general terms at least, of the major events which ultimately led to the creation of the Teton Landscape. Ancient volcanic and sedimentary rocks that were deposited some 3 billion years ago (we can’t say exactly when because their radiometric clocks were reset during metamorphosis) were recrystallized under tremendous temperature and pressure deep within the earth around 2.7 billion years ago, which produced the Web Canyon Gneiss. Some 130 million years later, these rocks were fractured and invaded by a massive igneous intrusion that crystallized into the Mount Owen Granite and associated pegmatite, which is around 2.55 billion years old. There is no need here to recite the entire geologic pedigree of our back yard, but it is interesting to note that the age of dinosaurs was a startlingly recent event when compared to the age of most of the rocks in the Teton Range. Likewise, the faulting which exposed the rocks of the Tetons to the light of day was mostly accomplished in the last 5 million years, which makes the dinosaurs suddenly seem ancient and the structure we refer to as the Tetons seem, well, as recent as recent can get for a geologist.
If there are a lot of us who possess a rudimentary understanding of our geologic history, there are even more of us who possess a strong sense of our cultural history. The first non-native American known to have set foot in the valley was John Colter, a mountain man and member of the Lewis and Clark Expedition (1804 -1806), who dropped in here (alone) in the winter of 1807 – 1808, which for practical purposes marks the beginning of our recorded history in this region and labels the insanely brave and adventurous Mr. Colter as ancient notwithstanding the fact that he arrived here some 5 million years after the Teton Range sprang forth and more than 4 million years after the first super eruptions at Yellowstone’s current location. Still, comparing the ancient John Coulter to the Teton topography makes our landscape seem mighty old and our oldest connection to the valley seem mighty recent.
There is somewhere between these two narratives a third perspective, which only a handful of people in the whole world are qualified to discuss. Here, we are examining that uncomfortable span of time that bridges the gap between what geologists call current and historians call pre-history – for present purposes the time between the retreat of the last ice age about 14,000 years ago and the arrival of the young John Colter in the winter of 1807. What was this area like after the last ice age and before the first white man? How was it different? What natural disasters, if any, befell this area before we “settled” it? This uncharted margin of science can only be effectively explored by a geoarchaeologist, and they are a rare breed. Fortunately for us, there is one within our membership ranks, and he has directed his multidisciplined talents to exactly these questions.
If you are curious about this time between times, you simply MUST come hear fellow GJH member Bill Eckerle this Tuesday (3/17/15) at the Teton County Library Auditorium at 6:00 pm. Bill is one of only a few scientists qualified to give us a nuanced view of the geologic, anthropologic, and ecologic changes during our prehistory.