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Site content related to keyword: "Bringhurst Gabbro"

Outcrop Bd44-b: Bringhurst Gabbro boulders in Shellpot Creek

Rock Outcrop Bd44-b: Bringhurst Gabbro boulders in Shellpot Creek

Found in the creek bed and flood plain, the large boulders in Shellpot Creek are excellent examples of Bringhurst Gabbro. The gabbro is very coarse-grained with crystals up to 2" long; however, variations in the grain size exist over a scale of a few inches. While observing this rock closely, one can occasionally find grains of orthopyroxene (possibly bronzite) up to 4" long. Some of the boulders have grains of olivine surrounded by double coronas of orthopyroxene, spinel, and hornblende.

Bringhurst Gabbro

Sbg

Coarse- to very coarse-grained gabbronoite with subophitic textures. Primary minerals are plagioclase, olivine, clinopyroxene and orthopyroxene. Olivine, where present, is surrounded by an inner corona of orthopyroxene and an outer corona of pargasitic hornblende, both with spinel symplectites. The gabbronorites locally contain abundant xenoliths of mafic Brandywine Blue Gneiss.

GM13 Geologic Map of New Castle County, Delaware

GM13 Geologic Map of New Castle County, Delaware

This map shows the surficial geology of New Castle County, Delaware at a scale of 1:100,000. Maps at this scale are useful for viewing the general geologic framework on a county-wide basis, determining the geology of watersheds, and recognizing the relationship of geology to regional or county-wide environmental or land-use issues. This map, when combined with the subsurface geologic information, provides a basis for locating water supplies, mapping ground-water recharge areas, and protecting ground and surface water. Geologic maps are also used to identify geologic hazards, such as sinkholes and flood-prone areas, to identify sand and gravel resources, and for supporting state, county, and local land-use and planning decisions.

Map Scale: 
100,000
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