Kurt FriehaufPhotos from Structural Geology

Kurt Friehauf

When I first came to Kutztown, I taught structural geology - probably my second favorite branch of geology (after mineral deposits).  It was a lot of work to create that class because I built it up from scratch, trying to make it particularly useful to students who would graduate into jobs in the environmental and engineering geology fields.  Now we have a very excellent full time structural geologist (Dr. Sarah Tindall) who does a great job teaching her course.

Port ClintonPort Clinton - looking at slatey cleavage and bedding, trying to locate the axes of large scale folds

bloomsburgSo is this an anticline or a syncline?  My friend the geoarcheologist Bill Chadwick for scale.

bloosmburgSlatey cleavage at an angle to bedding.  The angle between slatey cleavage and bedding is different in different parts of the fold and can be used to help you locate yourself within large structures.

bloomsburgA fault is simply a crack in the rock along which the two blocks of rock slide past one another.  Slickenlines are mineral growths that are aligned with the direction of slip along a fault.  Studying slickenlines thus allows us to determine the direction of movement along a fault (and thus deduce the forces/stresses that caused the deformation!)

martinsburg-shawangunkMe standing on a tilted angular unconformity.  Prior to folding during the Permian Allegheny orogeny that formed the modern Appalachian mountains, the boundary between the old, eroded surface of the Ordovician Martinsburg Formation (450 million years old) and the younger, Silurian age Shawangunk Formation (425 million years old) on which I'm "standing" would have been horizontal.

martinsburg-shawangunkThere is a nice bed of conglomerate at the base of the Shawangunk Formation - very typical of angular unconformities.

pencil cleavagePencil cleavage in slate at the nose of a fold at the Whale Back (Big Bear Coal Mine).  Slatey cleavage causes the rock to break perpendicular to bedding in the nose of folds because slatey cleavage forms perpedicular to the direction of maximum compression (sigma 1).  Breaks along both bedding and slatey cleavage form long pencil-shaped pieces typical of the noses of folds.

Out on the limbs of folds, slatey cleavage is almost parallel to bedding, so shales break up in flat disk-shaped plates instead of pencils. 

in classIn lab, we wanted to learn to distinguish between the effects of pure strain and simple shear.  We tried using homemade playdough models to measure the change of angles and lengths of reference axes.

in classAmane and Lea prepare their playdough models.  Amane works in Nevada now, and Lea went off to graduate school at the University of Alaska in Fairbanks to study geophysics.  Both of them were always great at math!
in classin classSimple shear changes angles between marker axes

in classAfter studying the effects of strain, we made three dimensional geologic structures (folds, faults, etc.) to see what map patterns would develop as erosion cut down into the models.  Three dimensional visualization is a strength with geologists.

in class.

gpsKnowing where you are on the map is essential for a geologist.  We learned to use high resolution differential GPS (Global Positioning System) instruments for this purpose.

gpsWe have two Trimble GPS units, so we split up into two groups.  Rich here was given the assignment to teach himself how to use the instrument and then teach six of his peers.  It's important to be able to teach yourself things!
Our nasty old building in the background has since been raised and replaced with a sunken "garden."



in class

drillingGeologists often work with drillers to get rock samples beneath the surface.  We had an engineering geology consulting company drilling on site to plan for some new buildings.  We visited them several times to learn how to log the types of rock that come out of the drillhole and, more germain to structural geology, measure the rock fracture characteristics. 

We studied drill core of bedrock as well as soil samples from the split spoon and hammer blow test.  The drillers were good guys!


drillingDrill core is stored in nice wooden boxes - a whole lot fancier than what I've been used to working in some mines.

drillingColleen really liked core because she could clearly see the different vein types and their relative ages.  I feel the same way - core is great! 

drillingColleen was an education major preparing to teach earth sciences in a high school.  She'll do a great job - she was always very enthusiastic and learned her lessons well.

drillingMarking the footage (depth in the hole) on the core box

drillingMeasuring the length of core and degree of fracturing.

drillingThe geologist who showed us her work was smart and enthusiastic.  It is a very nice job!


drillingThe consulting engineer explains RQD measurment (a way of quantifying rock fracture characteristics of the bedrock)





worst fieldtrip I ever led due to very loud nearby trafficMore fieldwork mapping folds in the Appalachian Mountains.  We were working near a very busy road, so everyone's wearing reflector vests (except the gentlman who had to sit things out in the vans!)

worst fieldtrip I ever led due to very loud nearby trafficI use a white board in the field so I can still sketch maps, outcrop drawings, Mohr circles, etc.  It's small enough that it doesn't cause me trouble unless I'm climbing in a place that I probably shouldn't have students, so... no problem!


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