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 |
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 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]
Baltimore Gabbro Complex is Paleozoic, post-lower Ordovician. [6]
Granite is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies underground. It is common in the continental crust of Earth, where it is found in igneous intrusions. These range in size from dikes only a few centimeters across to batholiths exposed over hundreds of square kilometers.
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 chemically equivalent to rapid-cooling, fine-grained basalt. Much of the Earth's oceanic crust is made of gabbro, formed at mid-ocean ridges. Gabbro is also found as plutons associated with continental volcanism. Due to its variant nature, the term gabbro may be applied loosely to a wide range of intrusive rocks, many of which are merely "gabbroic". By rough analogy, gabbro is to basalt as granite is to rhyolite.
Jessup is an unincorporated community and census-designated place in Howard and Anne Arundel counties, about 15 miles (24 km) southwest of Baltimore, Maryland, United States. Per the 2020 census, the population was 10,535.
A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to manage their safety risks and reduce their environmental impact.
Guilford is an unincorporated community located in Howard County in the state of Maryland. The location is named after the Guilford Mill. Guilford is near Kings Contrivance, one of the nine "villages" of Columbia.
Quartz monzonite is an intrusive, felsic, igneous rock that has an approximately equal proportion of orthoclase and plagioclase feldspars. It is typically a light colored phaneritic (coarse-grained) to porphyritic granitic rock. The plagioclase is typically intermediate to sodic in composition, andesine to oligoclase. Quartz is present in significant amounts. Biotite and/or hornblende constitute the dark minerals. Because of its coloring, it is often confused with granite, but whereas granite contains more than 20% quartz, quartz monzonite is only 5–20% quartz. Rock with less than five percent quartz is classified as monzonite. A rock with more alkali feldspar is a syenite whereas one with more plagioclase is a quartz diorite. The fine grained volcanic rock equivalent of quartz monzonite is quartz latite.
Savage is an unincorporated community and census-designated place located in Howard County, Maryland, United States, approximately 18 miles (29 km) south of Baltimore and 21 miles (34 km) north of Washington, D.C. It is situated close to the city of Laurel and to the planned community of Columbia. As of the 2020 census, it had a population of 7,542. The former mill town is a registered historic place, and has several original buildings preserved within and around the Savage Mill Historic District.
Charnockite is any orthopyroxene-bearing quartz-feldspar rock formed at high temperature and pressure, commonly found in granulite facies’ metamorphic regions, sensu stricto as an endmember of the charnockite series.
Granodiorite is a coarse-grained (phaneritic) intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar.
Monzonite is an igneous intrusive rock, formed by slow cooling of underground magma that has a moderate silica content and is enriched in alkali metal oxides. Monzonite is composed mostly of plagioclase and alkali feldspar.
Granite is an unincorporated community in Baltimore County, Maryland, United States. Originally known as Waltersville, it was renamed Granite in recognition of its principal product. The village was the center of this industry, which during its peak in the late 19th century provided building materials for major projects throughout the eastern seaboard.
Whiskey Bottom Road is a historic road north of Laurel, Maryland that traverses Anne Arundel and Howard Counties in an area that was first settled by English colonists in the mid-1600s. The road was named in the 1880s in association with one of its residents delivering whiskey after a prohibition vote. With increased residential development after World War II, it was designated a collector road in the 1960s; a community center and park are among the most recent roadside developments.
The Guilford Quartz Monzonite is a Silurian or Ordovician quartz monzonite pluton in Howard County, Maryland. It is described as a biotite-muscovite-quartz monzonite which occurs as discontinuous lenticular bodies which intrude mainly through the Wissahickon Formation (gneiss).
The Woodstock Quartz Monzonite is a Silurian or Ordovician quartz monzonite pluton in Baltimore County, Maryland. It is described as a massive biotite-quartz monzonite which intrudes through the Baltimore Gneiss at a single locality surrounding the town of Granite, Maryland.
The Ellicott City Granodiorite is a Silurian or Ordovician granitic pluton in Howard and Baltimore Counties, Maryland. It is described as a biotite granodiorite along the margin of the intrusion which grades into a quartz monzonite in its core. It intrudes through the Wissahickon Formation and the Baltimore Gabbro Complex.
The Port Deposit Gneiss is a Paleozoic gneiss formation in Cecil County, Maryland. It is described as a "Moderately to strongly deformed intrusive complex, chiefly composed of quartz diorite gneiss. Rock types include gneissic biotite-quartz diorite, hornblende-biotite-quartz diorite, and biotite granodiorite, with minor amounts of quartz monzonite and hornblende-quartz diorite. Moderate protoclastic foliation grades into strong cataclastic shearing." It intrudes into the Volcanic Complex of Cecil County.
The geology of Wisconsin includes Precambrian crystalline basement rock over three billion years old. A widespread marine environment during the Paleozoic flooded the region, depositing sedimentary rocks which cover most of the center and south of the state.
The Lilesville Granite, also referred to as the Lilesville pluton, is a ring-shaped body of granitic rock that spans about 94 square miles (240 km2) in Anson, Richmond, and Montgomery Counties in southern North Carolina.