Woodstock Quartz Monzonite

Woodstock Quartz Monzonite
Stratigraphic range: Silurian or Ordovician
Photographed on a boulder in Granite, Maryland
Typeigneous
Area~400 Ha
Lithology
Primarymonzonite
Location
RegionPiedmont of Maryland
CountryUnited States
ExtentWestern Baltimore County
Type section
Named forWoodstock, Maryland
Named byWilliams and Darton, 1892

The Woodstock Quartz Monzonite is a Silurian or Ordovician quartz monzonite pluton in Baltimore County, Maryland. It is described as a massive biotite-quartz monzonite which intrudes through the Baltimore Gneiss at a single locality surrounding the town of Granite, Maryland.

The extent of this intrusion was originally mapped in 1892 as the "Woodstock granite". It was given its current name in 1964 by C. A. Hopson. Hopson grouped the Woodstock Quartz Monzonite with the Ellicott City Granodiorite and the Guilford Quartz Monzonite as "Late-kinematic intrusive masses."

Woodstock granite has been used in the Capitol Building, the Library of Congress, and in buildings in Baltimore.