Arabia Mountain
Encyclopedia
Arabia Mountain is a monadnock
Monadnock
A monadnock or inselberg is an isolated rock hill, knob, ridge, or small mountain that rises abruptly from a gently sloping or virtually level surrounding plain...

 in DeKalb County, Georgia
DeKalb County, Georgia
DeKalb County is a county located in the U.S. state of Georgia. The population of the county was 691,893 at the 2010 census. Its county seat is the city of Decatur. It is bordered to the west by Fulton County and contains roughly 10% of the city of Atlanta...

. The peak is 940 feet (287m) above sea level, rising 180 feet (55m) above Arabia Lake reservoir. It is now part of the Davidson-Arabia Mountain Nature Preserve, a DeKalb County park.

Geology and history

On October 12, 2006, the mountain and adjoining features were designated Arabia Mountain National Heritage Area
U.S. National Heritage Area
A National Heritage Area is a site designated by United States and intended to encourage historic preservation of the area and an appreciation of the history and heritage of the site...

. Guided hikes are led by park rangers Tyrone "Tyrone of Arabia" Burkette and Brittany "Ranger Britt" Camp. Panola Mountain is 3 miles 5 furlongs (5.9 km) to the southwest. While designated as one peak on USGS maps, most users familiar with the area consider the rock formation to be two peaks: Arabia Mountain to the northeast, and Bradley Mountain to the southeast, connected by a low saddle.

Arabia Mountain appears to be composed of granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...

, like other nearby peaks such as Stone Mountain
Stone Mountain
Stone Mountain is a quartz monzonite dome monadnock in Stone Mountain, Georgia, United States. At its summit, the elevation is 1,686 feet amsl and 825 feet above the surrounding area. Stone Mountain granite extends underground at its longest point into Gwinnett County...

 and Panola Mountain
Panola Mountain
Panola Mountain is a granite monadnock near Stockbridge on the boundary between Henry County and Rockdale County, Georgia. The peak is above sea level, rising above the South River. The South River marks the boundary between Henry/Rockdale counties and DeKalb County, Georgia...

. Although made of metamorphic rock
Metamorphic rock
Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...

, the mountain is actually composed of migmatite
Migmatite
Migmatite is a rock at the frontier between igneous and metamorphic rocks. They can also be known as diatexite.Migmatites form under extreme temperature conditions during prograde metamorphism, where partial melting occurs in pre-existing rocks. Migmatites are not crystallized from a totally...

, metamorphosed at higher temperatures than gneiss
Gneiss
Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks.-Etymology:...

 but not sufficiently melted to become granite.

Like Panola Mountain and Stone Mountain, Arabia Mountain was quarried for decades before the property was turned over to the DeKalb park system. Structures and excavations from the quarry
Quarry
A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...

 operations can be seen throughout the park. Parts of the mountain were used for filming the 1992 horror film "Pet Sematary Two".

Botany and endangered plants

Arabia Mountain is one of five locations in the US where black-spored quillwort (Isoetes melanospora
Isoetes melanospora
Isoetes melanospora, commonly known as black-spored quillwort or black-spored Merlin's grass, is a rare and endangered aquatic pteridophyte endemic to the U.S. States of Georgia and South Carolina. It grows exclusively in shallow, temporary pools on granite outcrops, often with only 2 cm of soil...

) are found. It is one of 44 locations in the US where little amphianthus (Amphianthus pusillus
Gratiola amphiantha
Gratiola amphiantha is a rare species of flowering plant known by the common names little amphianthus, pool sprite and snorkelwort. It was previously the only species in the monotypic genus Amphianthus, but it was moved to genus Gratiola after genetic analysis in 2008...

) is found. These are endangered species protected by Georgia and Federal law. The largest and most important population of black-spored quillwort and one of the largest Amphianthus populations occur here. The U.S. Fish and Wildlife Service's five-year review of these species, completed in 2008, states that "enforcement to protect sensitive areas needs improvement" in the Arabia Mountain area.

Arabia Mountain is one of a small number of locations in the southeastern United States where Small's stonecrop
Crassulaceae
Crassulaceae, or the orpine family, are a family of dicotyledons. They store water in their succulent leaves. They are found worldwide, but mostly occur in the Northern Hemisphere and southern Africa, typically in dry and/or cold areas where water may be scarce...

 (Diamorpha smallii
Diamorpha
Diamorpha is a genus of family Crassulaceae. It is monotypic, including only the species Diamorpha smallii , an endemic of the southeastern United States. It becomes active in late fall and winter, blooms in late March, then dies. It has red succulent leaves that act to reflect light and hold...

) thrives (this plant is not listed as an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...

 in Georgia or the US, but is in Tennessee). When granite and similar stone outcrops are exposed to erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

, over time, small depressions, called solution pools, form where weaker rock wears away faster than surrounding rock (often assisted by lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...

). Over time, these depressions fill with sand washed down from higher locations, which accumulates a small amount of organic
Soil organic matter
Organic matter is matter that has come from a once-living organism; is capable of decay, or the product of decay; or is composed of organic compounds...

 content from decaying dead leaves and other detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...

, as well as rain water. Small's stonecrop then takes hold in these sandy hollows.

Bicycle trail

The PATH Foundation
PATH (Atlanta)
PATH Foundation is a network of off-road trails in and around the metro Atlanta area for walkers, runners, skaters, and cyclists. The foundation was established in 1991. The goal was to develop a network of off-road trails in Atlanta in time for use during the 1996 Summer Olympics. The trails are...

 has completed approximately 12 miles (19.3 km) of a 12 feet (3.7 m) concrete road for pedestrian and bicycle use running from downtown Lithonia
Lithonia, Georgia
Lithonia is a suburban town in eastern DeKalb County, Georgia, incorporated as a city. Lithonia's population was 1,924 at the 2010 census.-Geography:...

 to Stonecrest Mall
Mall at Stonecrest
The Mall at Stonecrest is an indoor shopping mall in Lithonia, Georgia, along Interstate 20 in eastern metro Atlanta...

 and thence through the Davidson-Arabia Mountain Nature Preserve to Panola Mountain State Park
Panola Mountain
Panola Mountain is a granite monadnock near Stockbridge on the boundary between Henry County and Rockdale County, Georgia. The peak is above sea level, rising above the South River. The South River marks the boundary between Henry/Rockdale counties and DeKalb County, Georgia...

. This includes a spur to a parking area on Klondike Road and a spur to the DeKalb County School System
DeKalb County School System
DeKalb County School System is a school district headquartered at 1701 Mountain Industrial Boulevard in unincorporated DeKalb County, Georgia, United States...

's Murphey Candler Elementary School and Arabia Mountain High School.

This trail will link with the proposed 26 miles (41.8 km), paved, 12 feet (3.7 m) South River bicycle trail extending to the 2000 acres (8.1 km²) Monastery of the Holy Spirit in Conyers
Conyers, Georgia
Conyers is the only city in Rockdale County, Georgia, USA. It is twenty-four miles east of Atlanta. As of the 2000 census, the city population was 10,689. Census estimates of 2005 indicate a population of 12,205. The city is the county seat of Rockdale County. By 2009, the reported population was...

.

Arabia Mountain High School

On the edge of the Arabia Mountain green space is the Arabia Mountain High School Academy of Engineering Medicine and Environmental Studies, opened August 2009. The Academy is a LEED
Leadership in Energy and Environmental Design
Leadership in Energy and Environmental Design consists of a suite of rating systems for the design, construction and operation of high performance green buildings, homes and neighborhoods....

-certified building and uses the "Environment as an Integrating Context for learning" (EIC) curriculum. The high school is connected to the nature preserve via a spur bicycle path.

External links

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