Baltimore Gabbro Complex
Baltimore Gabbro Complex is a hypersthene gabbro with subordinate amounts of olivine gabbro, norite, anorthositic gabbro, and pyroxenite. Igneous minerals and textures are well preserved in some rocks, and other rocks exhibit varying degrees of alteration and recrystallization with a new metamorphic mineral assemblage.[1]
| Baltimore Gabbro Stratigraphic range: Late Precambrian | |
|---|---|
| Type | Igneous |
| Location | |
| Region | Piedmont of Maryland |
| Extent | Howard and Baltimore Counties |
| Type section | |
| Named for | Baltimore, Maryland |
| Named by | G. H. Williams 1866 |
Early Quarrying
Baltimore Gabbro Complex was an early roadbed material for the Central Maryland Region. It was specified as "trap" or "nigger-head". It was mined in the Stoney Forest area of Harford and Cecil Counties, along the Susquehanna in Baltimore and as far south as Laurel.[2]
In 1996, Kingdon Gould III's Laurel Sand and Gravel company which includes Fairfax Materials, Allegany Aggregates, Laurel Asphalt and S.W. Barrick & Sons purchased the 600 acres chase property north of the historic town of Savage, Maryland. The site is home to the Savage Stone quarry, mining Baltimore Gabbro for road bed construction. The material is amble to support 50,000 pounds per square inch for road construction. The facility started operations in 2005 after special zoning approval with a 25-year reserve in materials.[3][4][5]
Age
Baltimore Gabbro Complex is Paleozoic, post-lower Ordovician.[6]
References
- "USGS Baltimore Gabbro Complex". Retrieved 14 August 2014.
- Report on the Highways of Maryland, Volume 1. Maryland Geological Survey. 1899. p. 89.
- "Residents OK quarry in Jessup". The Baltimore Sun. June 3, 1994.
- "Savage quarry quandary Howard County: Hazardous quarry poses tough questions for county officials". The Baltimore Sun. 26 September 1995.
- "Construction Equipment Guide". Retrieved 10 April 2014.
- Grace C. Keroher. Lexicon of Geologic Names of the United States for 1936-1960, Part 1. p. 207.