First State Geology has been the newsletter of DGS for over 25 years. 
Biotite Tonalite
Sbt
Fine- to medium-grained, equigranular biotite tonalite usually occurring as rounded boulders. Tonalites are leucocratic (15 to 25% modal mafic minerals), light gray to buff on fresh surfaces, and locally contain mafic enclaves with reddish rims, the result of iron hydroxide staining. Possibly intrusive into the Perkins Run Gabbronorite Suite.
GM10 Bedrock Geologic Map of the Piedmont of Delaware and Adjacent Pennsylvania
This is a map of the crystalline bedrock units in the Piedmont of Delaware and adjacent Pennsylvania. The southern boundary of the mapped area is the updip limit of the Potomac Formation (Woodruff and Thompson, 1972, 1975). Soil, regolith, and surficial deposits of Quaternary age are not shown.
This page tagged with:
- Appalachian Piedmont
- arc affinity
- Arden Granite
- Ardentown Granitic Suite
- Baltimore Gneiss
- Barley Mill Gneiss
- bedrock
- Brandywine Blue Gneiss
- Bringhurst Gabbro
- Christianstead Gneiss
- Cockeysville Marble
- Cretaceous Period
- cross-sections
- Faulkland Gneiss
- Iron Hill Gabbro
- mapping
- Metapyroxenite and metagabbro (undifferentiated)
- Mill Creek Metagabbro
- New Castle County
- Newark
- Pegmatite
- Pennsylvanian Period
- Permian Period
- Rockford Park Gneiss
- rocks
- Serpentinite
- Setters Formation
- Upper Cretaceous
- wetlands
- Wilmington
- Wilmington Complex
- Windy Hills Gneiss
- Wissahickon Formation
- Carboniferous Period
- Jurassic Period
- Lower Cretaceous
- Mississippian Period
- Devonian Period
- Triassic Period
- Silurian Period
- Ordovician Period
- Cambrian Period
- Mesozoic Era
- Paleozoic Era
- Precambrian
GM4 Geology of the Wilmington Area, Delaware
Crystalline bedrock geology of the Wilmington area, Delaware.
This page tagged with:
- Appalachian Piedmont
- Arden Granite
- Bringhurst Gabbro
- Cretaceous Period
- cross-sections
- mapping
- New Castle County
- Pennsylvanian Period
- Permian Period
- rocks
- subsurface
- surficial geology
- Upper Cretaceous
- Wilmington
- Wilmington Complex
- Wissahickon Formation
- Carboniferous Period
- Jurassic Period
- Lower Cretaceous
- Mississippian Period
- Devonian Period
- Triassic Period
- Silurian Period
- Ordovician Period
- Cambrian Period
- Mesozoic Era
- Paleozoic Era
- Precambrian
DGS Geologic Map No. 10 (Bedrock Geologic Map of the Piedmont of Delaware and Adjacent Pennsylvania) Dataset
The vector and raster data sets contains the rock unit polygons for the surficial geology for DGS Geologic Map No. 10. This map is of the crystalline bedrock units in the Piedmont of Delaware and adjacent Pennsylvania.
This page tagged with:
- Appalachian Piedmont
- ArcGIS
- Arden Granite
- Ardentown Granitic Suite
- Baltimore Gneiss
- Barley Mill Gneiss
- bedrock
- Brandywine Blue Gneiss
- Bringhurst Gabbro
- Christianstead Gneiss
- Cockeysville Marble
- cross-sections
- Faulkland Gneiss
- Iron Hill Gabbro
- mapping
- Metapyroxenite and metagabbro (undifferentiated)
- Mill Creek Metagabbro
- New Castle County
- Pegmatite
- Pennsylvania
- Quantum GIS
- Rockford Park Gneiss
- rocks
- Serpentinite
- Setters Formation
- wetlands
- WFS Feature Service
- Wilmington Complex
- Windy Hills Gneiss
- Wissahickon Formation
- WMS Map Service
- Shapefile
