Mid-Atlantic Iron Belt Project - Phase 3 - Rittenhouse Gap Detailed Geophysical Survey

Kurt Friehauf - Kutztown University

Rittenhouse Geophysics - February 2003
Rittenhouse Geophysics February 2003Four undergraduates student involved:

Rittenhouse Geophysics - MarchProject: The successful linear traverses in the phase 2 reconnaissance study gave only a one-dimensional view of the geophysics of the study area.   We did a follow-up study in the Autumn on a 20 x 30 meter plot to prove that we could use the GPS directly for data location once the tree canopy was clear and see if we could identify magnetic variations across a 2-dimensional (map) surface.  Rittenhouse Geophysics - MarchWe also wanted to see if we could identify regions of rock adjacent to the magnetite iron ore veins that had been depleted of iron due to chemical interaction with the hot, geothermal waters that deposited the veins and try to put tighter constraints on the geometry of the veins so that we could say something about the rock fracturing mechanism that created the veins in the first place.  The success of the 2-dimensional characterization survey led to expansion of the map area to include a much larger part of the overall mining district.  In all, we’ve collected over 4,000 measurements in the study area to date.

Rittenhouse Geophysics - February 2003Results:  The spring of 2003 was a relatively harsh one with weekly snowstorms that occurred primarily on Thursdays, Fridays, and Saturdays.  Satellite positioning also required pre-dawn work to ge the best GPS resolution.  Rittenhouse Geophysics - February 2003Although the weather made for uncomfortable conditions, the snow on the ground aided in efficient data collection because each data site could be clearly marked for each successive measurement, thereby allowing us to take data more quickly.  The snow and freezing rain also made the study a good character-building exercise for all involved.  The data collected suggest we are able to distinguish between “fresh rocks,” rocks that were chemical altered by the geothermal waters, and magnetite veins.  Rittenhouse Geophysics - February 2003The geometric relationship between two of the veins suggests the iron ore occurred as one vein that was broken and offset by faults later on rather than by infilling of an originally en echelon fracture set.

Rittenhouse Geophysics - February 2003Rittenhouse Geophysics - February 2003Grants:  Students wrote successful Kutztown University Undergraduate Research grant proposal that funded travel to the Geological Society of America Northeast Section meeting in Halifax, Nova Scotia, Canada

Rittenhouse Geophysics group in HalifaxPublication: Hoefert Catherine M., Burris, Lea, Yenchik, John, Black, Laurel E., and Friehauf, Kurt C., 2003, Mappin' Without Diggin': An Application of Magnetometry Techniques in Rittenhouse Gap Mining District in Berks County, Pennsylvania:  Geological Society of America Abstracts with Programs Vol. 35, No. 3.  (All four students traveled and presented their work with me at this meeting in Halifax, Nova Scotia, Canada)

Rittenhouse Geophysics - MarchFollow-up:  Will try to organize students in the Geophysics course to fill in gaps in the data as a class project.  Pending success of the overall map, I will propose the Pennsylvania Geological Survey publish the data as a miscellaneous field investigation.

on to Phase 4 - Studies of other deposits in the region

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