The Albemarle Group is a
geologic group
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Eart ...
in
North Carolina composed of
metamorphosed mafic and
felsic
In geology, felsic is a modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz.Marshak, Stephen, 2009, ''Essentials of Geology,'' W. W. Norton & Company, 3rd ed. It is contrasted with mafic rocks, whi ...
volcanic rock,
sandstone,
siltstone
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...
,
shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...
, and
mudstone
Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...
.
It is considered part of the Carolina Slate Belt and covers several counties in central North Carolina. It preserves
fossils
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...
dating back to the
Ediacaran
The Ediacaran Period ( ) is a geological period that spans 96 million years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian Period 538.8 Mya. It marks the end of the Proterozoic Eon, and th ...
period in the Floyd Church member.
Description
All five members of the Albemarle Group are composed of metamorphosed volcanic and sedimentary rocks. The Albemarle Group covers parts of
Anson,
Davidson,
Carbarrus,
Montgomery,
Randolph Randolph may refer to:
Places In the United States
* Randolph, Alabama, an unincorporated community
* Randolph, Arizona, a populated place
* Randolph, California, a village merged into the city of Brea
* Randolph, Illinois, an unincorporated commun ...
,
Rowan
The rowans ( or ) or mountain-ashes are shrubs or trees in the genus ''Sorbus
''Sorbus'' is a genus of over 100 species of trees and shrubs in the rose family, Rosaceae. Species of ''Sorbus'' (''s.l.'') are commonly known as whitebeam, r ...
,
Stanly, and
Union counties. It is part of the Carolina Slate Belt, which is characterized by metamorphic volcanic rich sedimentary rocks.
The Albemarle Group falls in the
Piedmont region of North Carolina.
History
Formations have been added, removed, and renamed several times since the Ablemarle Group was first proposed.
The first three members were, from oldest to youngest, the Tillery Formation, the McManus Formation, and the Yadkin
Greywacke. The McManus Formation name was abandoned, and the
Cid Formation was proposed with two members: the Flat Swamp member and an unnamed mudstone member. Parts of the McManus Formation became the Millingport Formation with two members: the Yadkin Member (formerly the Yadkin Greywacke) and the Floyd Church member.
Another revision abandoned the Millingport Formation name, and gave formation status to the Yadkin Formation and the Floyd Church Formation. The McManus terminology has been used by later papers,
but had not been adopted by the
USGS or the North Carolina Geological Survey.
See also
*
List of fossiliferous stratigraphic units in North Carolina
References
* {{cite web, title= Fossilworks: Gateway to the Paleobiology Database, author= ((Various Contributors to the Paleobiology Database)), url= http://www.fossilworks.org/cgi-bin/bridge.pl?action=home, access-date= 17 December 2021
Geologic groups of North Carolina