sjudge June 8th, 2013
EPHRAIM, UTAH — Generations of Wooster geologists were united today over a common interest: deformation bands of Utah!!
George Davis (Regents Professor Emeritus and Provost Emeritus, University of Arizona) researched the deformation bands of the Colorado Plateau region of Utah and wrote several very detailed manuscripts. As we work on a structural analysis of the Sixmile Canyon Formation, we have been using two of his publications rather extensively this past week: “Structural Geology of the Colorado Plateau Region of Southern Utah, with Special Emphasis of Deformation Bands”…and…”Conjugate Riedel Deformation Band Shear Zones”.
I actually thought that it was a unique twist of fate that Tricia and I were pouring over two of George’s publications last night…and putting our knowledge into use today in the field.
Above is a view of the Sixmile Canyon Formation, the focus of Tricia’s study. It contains wonderful deformation bands and joints, and it just happens to be located next to two characteristic antithetic normal faults that cut the Wasatch Plateau.
Tricia and I stumbled upon these deformation bands early in the morning…
…and these later in the afternoon. With all of the deformation bands in the area, we felt like “measuring machines”. Indeed, we could have used help in the field today from fellow Brunton-lovers!!
In addition to looking for conjugate deformation bands that George describes from his work in southern Utah, we were also trying to identify characteristic “ladder structures” that he identified in the Sheets Gulch area. Tricia is sampling the deformation bands for further thin section analyses to determine if they show any sign of cataclasis. Ultimately, she would like to classify the deformation bands, using one of the kinematic classification schemes proposed in the literature.
Here’s Tricia gathering what she considers to be a “small” sample from a prominent deformation band. You can tell how excited she is about her I.S.!!
One characteristic of this part of the Sixmile is the interesting iron “concretions” that are everywhere. The photo above shows how abundant that they can be within the unit.
Aren’t these awesome??!! These iron “chimneys” rise right out of the rock. Tricia and I will be further investigating the abundance of morphologies of these concretions tomorrow, as we try to tackle some interesting paleo-fluid fronts within the Sixmile. The past two days have been rather safe in the field, because we saw few mountain lion prints at our localities. But, tomorrow is another day, and we are hiking back up to the areas where we saw extensive mountain lion “trace fossils”.