Norbeck Intrusive Suite

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Norbeck Intrusive Suite
Stratigraphic range: Ordovician
Norbeck Intrusive Suite tonalite a 20230802.jpg
Outcrop of tonalite at Greenwood Local Park, Brookeville
Typeigneous
Lithology
Primary tonalite, metadiorite, metagabbro
Location
Region Piedmont of Maryland
ExtentMontgomery County
Type section
Named for Norbeck, Maryland
Named byC. A. Hopson, 1964 [1]

The Norbeck Intrusive Suite is an Ordovician granitic pluton in Montgomery County, Maryland. The intrusive suite was originally mapped as the Norbeck Quartz Diorite by Hopson, [1] and is shown as such on the Geologic Map of Maryland of 1968. [2] A. A. Drake later revised the name after more detailed mapping. [3] It intrudes through the Wissahickon Formation.

Description

Three lithologies were mapped in the Kensington quadrangle by Drake: [3]

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References

  1. 1 2 Hopson, C.A., 1964, The crystalline rocks of Howard and Montgomery Counties: Maryland Geological Survey County Report, 337 p., (Reprinted from Cloos, Ernst, and others, "Geology of Howard and Montgomery Counties," p. 27-215)
  2. Geologic Map of Maryland, 1968. Maryland Geological Survey.
  3. 1 2 Drake, A.A., Jr., 1998, Geologic map of the Kensington quadrangle, Montgomery County, Maryland: U.S. Geological Survey Geologic Quadrangle Map, GQ-1774, scale 1:24,000