RIPPLES IN THE ROCK

In your lone, silent traipsing through the Uintas, have you ever walked across a long sloping rock surface, sometimes as long as a small meadow, and stopped to examine the ancient, intricate incisions and ripples cut into the stone beneath your boots?

According to the article, "Classification of Ripple Marks," by Lee High of Oberlin College and M. Dane Picard of the University of Utah (Utah Geology, Spring l977), these ripple marks are used in paleogeographic and environmental reconstruction and can be separated into four types: wave formed, current formed, interference, and eolian. Current ripples are those formed by unidirectional water currents (e.g. streams, tides, turbidity flows and includes wave-drift currents in shallow water); eolian are caused by wind (cleverly named, I suppose, after Aeolus, the Greek god of wind.)

Most common criteria for ripple classification are crest pattern, symmetry, and internal structure, while ripple spacing, crest roundness, grain size distributions, and amplitude are also useful in typing. The Uintas are cited throughout the article as evidence of linear asymmetric ripples from the Triassic (Moenkopi Formation). It is this type I depict in the illustration accompanying this article, drawn from a photo in the article cited.

While this information is taken from an article written 25 years ago, a mere blip on the paleogeographic timeline, it is probably germane to what we see in our wanderings. If you know something more current about the ripple marks, or a totally different natural phenomenon found there, why not contribute to our next issue? Your editor is always on the prowl to discover fascinating natural history notes to add to our common knowledge of the Uintas we so love.

Margaret Pettis