Norbeck Intrusive Suite

{{Infobox rockunit

| name = Norbeck Intrusive Suite

| image = Norbeck Intrusive Suite tonalite a 20230802.jpg

| caption = Outcrop of tonalite at Greenwood Local Park, Brookeville

| type = igneous

| age = Ordovician

| prilithology = tonalite, metadiorite, metagabbro

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| namedfor = Norbeck, Maryland

| namedby = C. A. Hopson, 1964Hopson, 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)

| region = Piedmont of Maryland

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| extent = Montgomery County

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}}

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, and is shown as such on the Geologic Map of Maryland of 1968.[http://www.mgs.md.gov/esic/geo/index.html Geologic Map of Maryland], 1968. Maryland Geological Survey. A. A. Drake later revised the name after more detailed mapping.Drake, A.A., Jr., 1998, [https://ngmdb.usgs.gov/Prodesc/proddesc_13133.htm Geologic map of the Kensington quadrangle], Montgomery County, Maryland: U.S. Geological Survey Geologic Quadrangle Map, GQ-1774, scale 1:24,000 It intrudes through the Wissahickon Formation.