Geology and Geophysics of the
Rittenhouse Gap Iron Mine and the Mid-Atlantic Iron Belt, Berks County,
Pennsylvania
(and beyond)
Kurt Friehauf - Kutztown
University of Pennsylvania
Overview
Beginning
in colonial times and continuing through the Civil War, eastern
Pennsylvania was an important source of our nation’s iron, feeding
furnaces with ore to make cannon and machinery. Most of this iron
came from relatively small deposits of a few thousands of tons of
magnetite ore in very old granitic and metamorphic rocks, although
several multi-million ton orebodies also occur in the area in younger
limestones. The belt of mines stretches through northern New
Jersey and into southern New York and is known as the Mid-Atlantic Iron
Belt.
Like many iron deposits in eastern Pennsylvania, the Rittenhouse Gap
mine closed in the early 1900’s and nature has made great inroads in
reclaiming the landscape. Although iron mining in eastern
Pennsylvania and New Jersey ceased decades ago, the question of how the
iron deposits in this region originally formed, is a matter of active
debate in the geological scientific community.
At the core of the debate lie three key questions: 1) When did
the deposits form? 2) What was the source of the hot waters that
deposited the iron? And 3) Are all of the small deposits related
to one big, crustal scale geothermal system, or do the deposits
represent isolated events?
I've
been working with undergraduate students for the past few years to
try to unravel this little mystery. I've been very, very lucky to
have the help of Robert Smith of the Pennsylvania Geological
Survey and Richard Volkert of the New Jersey Geological Survey
- both are extraordinary guys. Limited exposures and
metamorphosed rocks make it a tough nut to crack, but we're having fun
working at it!
Beginning
in colonial times and continuing through the Civil War, eastern
Pennsylvania was an important source of our nation’s iron, feeding
furnaces with ore to make cannon and machinery. Most of this iron
came from relatively small deposits of a few thousands of tons of
magnetite ore in very old granitic and metamorphic rocks, although
several multi-million ton orebodies also occur in the area in younger
limestones. The belt of mines stretches through northern New
Jersey and into southern New York and is known as the Mid-Atlantic Iron
Belt.
I've
been working with undergraduate students for the past few years to
try to unravel this little mystery. I've been very, very lucky to
have the help of Robert Smith of the Pennsylvania Geological
Survey and Richard Volkert of the New Jersey Geological Survey
- both are extraordinary guys. Limited exposures and
metamorphosed rocks make it a tough nut to crack, but we're having fun
working at it!
