Baltimore Gabbro Complex is a

hypersthene Hypersthene is a common rock-forming inosilicate mineral belonging to the group of orthorhombic pyroxenes. Its chemical formula is . It is found in igneous and some metamorphic rocks as well as in stony and iron meteorites. Many references have f ...

gabbro Gabbro () is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is che ...

with subordinate amounts of

olivine The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...

gabbro,

norite Norite is a mafic intrusive igneous rock composed largely of the calcium-rich plagioclase labradorite, orthopyroxene, and olivine. The name ''norite'' is derived from ''Norge'', the Norwegian name for Norway. Norite also known as orthopyroxen ...

anorthositic Anorthosite () is a phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most c ...

gabbro, and

pyroxenite Pyroxenite is an ultramafic igneous rock consisting essentially of minerals of the pyroxene group, such as augite, diopside, hypersthene, bronzite or enstatite. Pyroxenites are classified into clinopyroxenites, orthopyroxenites, and the websteri ...

Igneous Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or ...

minerals and textures are well preserved in some rocks, and other rocks exhibit varying degrees of alteration and recrystallization with a new

metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causin ...

mineral assemblage.

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. In 1996,

Kingdon Gould III Kingdon Gould III (born June 16, 1948) is an American real estate developer, active in the Washington, D.C.-area. He is part of the fifth generation of the Gould family of financiers, philanthropists and diplomats, which includes his father Kingd ...

'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 Savage is an unincorporated community and census-designated place located in Howard County, Maryland, United States, approximately south of Baltimore and north of Washington, D.C. It is situated close to the city of Laurel and to the planned co ...

. 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.

Age

Baltimore Gabbro Complex is

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

, post-

lower Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The ...

References

{{Reflist Baltimore County, Maryland Howard County, Maryland Plutonic rocks Igneous petrology of Maryland Ordovician magmatism

Early Quarrying

Age

See also

References