Mappin' Without Diggin': An Application of
Magnetometry Techniques in the Rittenhouse Gap Mining District in Berks
County, Pennsylvania
Hoefert
Catherine
M.,
Burris, Lea, Yenchik, John, Black, Laurel E.,
and Friehauf, Kurt C.,
2003,
Mappin'
Without Diggin': An
Application of
Magnetometry Techniques in the Rittenhouse Gap Mining District in Berks
County, Pennsylvania [abs.]: Geological Society of America
Northeastern
Section - 38th Annual Meeting (March 27–29, 2003) Halifax, Nova Scotia,
Program with Abstracts, vol. 35, no. 3, p. 94.
Magnetite
veins in the Rittenhouse Gap iron-mining district located in Berks
County, Pennsylvania are parallel, but offset in a stepped fashion,
cutting Proterozoic granitic gneisses. Forest litter obscures all of
the outcrop, making geologic mapping difficult. We used a hand-held
proton procession magnetometer coupled with a GPS receiver, sampling
with a two-meter area, and compiled our data with GIS to map the
magnetic field in the iron-mining district. We interpreted the
variations in the magnetic data in terms of wall rock hydrothermal
alteration, calibrated by comparing magnetic data with petrographic
studies of rocks exposed in the iron-mine region. In order to determine
whether the district’s en echelon vein pattern reflects a large-scale
Reidel shear fracture, or offsets of a simple vein by cross faults, a
larger study area involving smaller grids of magnetometer readings
would generate a clearer and decisive underground petrology picture.
