1
Southern Appalachians
LAURENTIAN REALM (entire orogen)
Grenville basement of Laurentia including ca. 1 Ga inliers within the hinterland
Gneiss, schist, and plutonic rocks affected by the Grenville Orogeny and
associated post-orogenic granitoid bodies. Elk Park Plutonic Suite, Mount Holly
Complex, Disappointment Hill Complex
10
AXIAL REALM
PIEDMONT DOMAIN
Unseparated schist, gneiss, and migmatite; may include rocks as young as
Silurian. Contains detrital zircon populations distinct from those of units 7
and 9. Unnamed gneiss and schist east of Brindle Creek fault
11
GOOCHLAND DOMAIN
Metamorphic rocks of unknown origin
High-grade paragneiss, orthogneiss, and amphibolite of unknown affinity that
structurally overlie ca. 1 Ga basement of unit 1. Locally contains small bodies
of Devonian orthogneiss. Maidens Gneiss
12b_VOL_MAFIC
Northern Appalachians
Peri-Laurentian Arc System (Iapetan)
Mainly Lower to Upper Ordovician ophiolitic and magmatic-arc rocks with
associated sedimentary rocks; older strata contain Laurentian fauna. Volcanic
rocks (mafic). Hawley Formation, Snooks Arm Group
14a
PERI-GONDWANAN REALM
CAROLINIA
Suprastructural magmatic-arc and associated rocks
unconformity
Younger magmatic-arc/back-arc and overlying sequences ? Neoproterozoic to Lower
Paleozoic magmatic sequences with associated clastic sedimentary rocks;
generally <580 Ma. Albemarle Group
14a_INT_FELSIC
generally <580 Ma. Intrusive rocks (felsic). Albemarle Group
14a_VOL_FELSIC
generally <580 Ma. Volcanic rocks (felsic). Albemarle Group
14a_VOL_MAFIC
generally <580 Ma. Volcanic rocks (mafic). Albemarle Group
14b
Older magmatic arc ? Neoproterozoic magmatic-arc rocks with associated clastic
sedimentary rocks; generally >580 Ma. Virgilina Formation
14b_INT_FELSIC
sedimentary rocks; generally >580 Ma. Intrusive rocks (felsic). Virgilina
Formation
14b_INT_MAFIC
sedimentary rocks; generally >580 Ma. Intrusive rocks (mafic). Virgilina
14b_VOL_FELSIC
sedimentary rocks; generally >580 Ma. Volcanic rocks (felsic). Virgilina
14b_VOL_MAFIC
sedimentary rocks; generally >580 Ma. Volcanic rocks (mafic). Virgilina
14c
Unseparated magmatic and clastic sedimentary sequences. Spring Hope Formation
14d_MAFIC_OPH
Mafic-ultramafic complex of probable oceanic origin. Mafic components of an
ophiolite and areas of isolated ultramafic and metaultramafic bodies. Complex
of Halifax County
15
Infrastructural magmatic-arc/oceanic rocks
Gneiss, schist, metavolcanic rocks, and amphibolite, with local mélange and
ultramafic bodies. Locally yield Neoproterozoic to Cambrian radiometric ages.
Battleground Formation
15_INT_FELSIC
Intrusive rocks (felsic). Battleground Formation
15_INT_MAFIC
Intrusive rocks (mafic). Battleground Formation
15_SHEAR
Shear zone. Battleground Formation
15_UMAFIC_OPH
Ultramafic components of an ophiolite and areas of isolated ultramafic and
metaultramafic bodies. Battleground Formation
15_VOL_FELSIC
Volcanic rocks (felsic). Battleground Formation
15_VOL_MAFIC
Volcanic rocks (mafic). Battleground Formation
1_AMCS_BLUE
associated post-orogenic granitoid bodies. Anorthosite-mangerite-charnockite
suite rocks (gabbro, anorthosite). Elk Park Plutonic Suite, Mount Holly
1_AMCS_RED
suite rocks (mangerite, charnockite, granite). Elk Park Plutonic Suite, Mount
Holly Complex, Disappointment Hill Complex
1_INT_FELSIC
associated post-orogenic granitoid bodies. Intrusive rocks (felsic). Elk Park
Plutonic Suite, Mount Holly Complex, Disappointment Hill Complex
1_INT_MAFIC
associated post-orogenic granitoid bodies. Intrusive rocks (mafic). Elk Park
1_MAFIC_OPH
associated post-orogenic granitoid bodies. Mafic components of an ophiolite and
areas of isolated ultramafic and metaultramafic bodies. Elk Park Plutonic
Suite, Mount Holly Complex, Disappointment Hill Complex
1_ORTHOGNEISS
associated post-orogenic granitoid bodies. Orthogneiss. Elk Park Plutonic
1_PARAGNEISS
associated post-orogenic granitoid bodies. Paragneiss and metavolcanic rock.
Elk Park Plutonic Suite, Mount Holly Complex, Disappointment Hill Complex
1_SHEAR
associated post-orogenic granitoid bodies. Shear zone. Elk Park Plutonic Suite,
Mount Holly Complex, Disappointment Hill Complex
1_VOL_FELSIC
associated post-orogenic granitoid bodies. Volcanic rocks (felsic). Elk Park
1a
associated post-orogenic granitoid bodies. Basement components >= 1.5 Ga.
2
Iapetus rift facies
Encratonic magmatic rocks (ca. 750?680 Ma) and associated sedimentary rocks;
southern Appalachians. Grandfather Mountain Formation, Crossnore Complex
23
Mid-Paleozoic clastic wedge and time-equivalent rocks
on Laurentian Realm
Middle Ordovician to Lower Devonian, generally thin, shallow marine to
terrestrial, clastic sedimentary wedge with subordinate carbonate rocks and
chert. Includes unit 33 in southernmost Appalachians and carbonate rocks that
are either the cratonward equivalent of unit 6 or lie unconformably on rocks
deformed during the Taconic Orogeny. Tuscarora Formation, Tonoloway Formation,
Salina Group
24
Extensional basin and cover rocks
on southern Laurentian Realm
Upper Ordovician to Lower Mississippian clastic sedimentary rocks and
diamictite lying unconformably on unit 4. Talladega Group
25_INT_FELSIC
Mid-Paleozoic magmatism mainly in Axial Realm
Middle Ordovician to Lower Silurian plutonic rocks and orthogneiss mainly
confined to the Piedmont domain. Intrusive rocks (felsic). Shelton Granite
Gneiss, Cortlandt complex
25_INT_MAFIC
confined to the Piedmont domain. Intrusive rocks (mafic). Shelton Granite
26
Marine basin
on Axial Realm
Upper Ordovician slate, schist, quartzite, and conglomerate with minor
metavolcanic rocks. Arvonia Formation
2_INT_FELSIC
southern Appalachians. Intrusive rocks (felsic). Grandfather Mountain
Formation, Crossnore Complex
2_VOL_FELSIC
southern Appalachians. Volcanic rocks (felsic). Grandfather Mountain Formation,
Crossnore Complex
3
Neoproterozoic to Cambrian mainly clastic sedimentary rocks filling rift basins
and associated magmatism related to Iapetan rifting. Locally contains fragments
of oceanic crust. Ocoee Supergroup, Catoctin Formation, Pinnacle Formation,
Tibbit Hill Formation, Bateau Formation, Lynchburg Formation
32c
Syn-Acadian sedimentary and magmatic rocks
Upper Silurian to Lower Devonian plutonic rocks confined to Carolinia.
Concord-Salisbury Plutonic Suite
32c_INT_FELSIC
Intrusive rocks (felsic). Concord-Salisbury Plutonic Suite
32c_INT_MAFIC
Intrusive rocks (mafic). Concord-Salisbury Plutonic Suite
33
Acadian clastic wedge
Mainly Middle to Upper Devonian dominantly terrestrial clastic sedimentary
rocks deposited on the west flank (Catskill clastic wedge) and on interior
portions of the Appalachian Orogen; includes minor carbonate rocks. Hamilton
Group, Genesee Group, Sonyea Group
34
Middle Devonian to earliest Carboniferous plutonic rocks. Concord pluton, Deer
Isle Granite, South Mountain batholith, Ackley batholith
34_INT_FELSIC
Middle Devonian to earliest Carboniferous plutonic rocks. Intrusive rocks
(felsic). Concord pluton, Deer Isle Granite, South Mountain batholith, Ackley
batholith
35
Lower Mississippian to Lower Permian mainly terrestrial clastic sedimentary
rocks that form westward transgressive wedges; includes minor cratonal facies
near base.
35a
near base. Mauch Chunk-Pottsville clastic wedge. Mauch Chunk Group
35b
near base. Pennington-Lee clastic wedge. Lee Formation
35c
near base. Ouachita clastic wedge. Pottsville Group
37
Alleghanian plutonism
Carboniferous to Permian plutonic rocks. Rolesville batholith, Narragansett
Pier pluton, Sebago pluton
37_INT_FELSIC
Carboniferous to Permian plutonic rocks. Intrusive rocks (felsic). Rolesville
batholith, Narragansett Pier pluton, Sebago pluton
38a
Continental rift basins and magmatism related to formation of the Atlantic Basin
Alluvial and lacustrine clastic sedimentary rocks and local basalt, granite,
syenite, gabbro, and minor felsic volcanic rocks; rift basins immediately
preceding formation of the Atlantic Ocean. Newark Supergroup, North Mountain
Basalt, Wolfville Formation
38a_INT_MAFIC
preceding formation of the Atlantic Ocean. Intrusive rocks (mafic). Newark
Supergroup, North Mountain Basalt, Wolfville Formation
38a_VOL_MAFIC
preceding formation of the Atlantic Ocean. Volcanic rocks (mafic). Newark
39
Plutonic rocks of unknown age and origin. Greensboro intrusive suite
39_INT_FELSIC
Plutonic rocks of unknown age and origin. Intrusive rocks (felsic). Greensboro
intrusive suite
39_INT_MAFIC
Plutonic rocks of unknown age and origin. Intrusive rocks (mafic). Greensboro
3_INT_FELSIC
of oceanic crust. Intrusive rocks (felsic). Ocoee Supergroup, Catoctin
Formation, Pinnacle Formation, Tibbit Hill Formation, Bateau Formation,
Lynchburg Formation
3_UMAFIC_OPH
of oceanic crust. Ultramafic components of an ophiolite and areas of isolated
ultramafic and metaultramafic bodies. Ocoee Supergroup, Catoctin Formation,
Pinnacle Formation, Tibbit Hill Formation, Bateau Formation, Lynchburg Formation
3_VOL_FELSIC
of oceanic crust. Volcanic rocks (felsic). Ocoee Supergroup, Catoctin
3_VOL_MAFIC
of oceanic crust. Volcanic rocks (mafic). Ocoee Supergroup, Catoctin Formation,
4
Iapetus drift facies - passive margin sequence
Knox?Beekmantown?St. George unconformity
Lower Paleozoic basal transgressive clastic sequence and overlying dominantly
carbonate platform sequence containing local clastic rocks. Chilhowee Group,
Knox Group, Beekmantown Group, Philipsburg Group, Port au Port Group, Potsdam
Sandstone
5
Continental slope-and-rise facies; locally may contain oceanic volcanic rocks
and rift-facies rocks. Conestoga Limestone, Ottauquechee Formation,
Trois-Pistoles Group, Northern Head Group, West Castleton Formation
6a
Taconic clastic wedge
Westward-transgressive clastic wedges mainly derived from an eastern source and
associated carbonate rocks. Locally includes mélange. Lower Middle Ordovician
Sevier clastic wedge. Sevier Formation
6ab
Combined geological unit.
6b
associated carbonate rocks. Locally includes mélange. Middle to Upper
Ordovician Taconic clastic wedge; gradational with unit 23. Martinsburg
Formation, Walloomsac Formation
6c
associated carbonate rocks. Locally includes mélange. Lower to Upper Ordovician
Tourelle-Humber wedge; extends into Lower Silurian on Anticosti Island.
Tourelle Formation, Goose Tickle Group
7
Multiply tectonized accretionary complex
Neoproterozoic to Lower Paleozoic mainly clastic metasedimentary rocks, schist,
and gneiss containing metaclastic mélanges and subordinate amphibolite,
meta-ultramafic rocks, and eclogite. Locally associated with ca. 1 Ga gneiss of
unit 1. Likely includes rocks equivalent to units 1, 3, 4, 5, 6, 8, and 9. Ashe
Formation, Evington Group
7_MAFIC_OPH
unit 1. Likely includes rocks equivalent to units 1, 3, 4, 5, 6, 8, and 9.
Mafic components of an ophiolite and areas of isolated ultramafic and
metaultramafic bodies. Ashe Formation, Evington Group
7_SHEAR
Shear zone. Ashe Formation, Evington Group
7_UMAFIC_OPH
7a
Metaclastic rocks and amphibolite of the Smith River allochthon; metaclastic
rocks yield Early Cambrian monazite ages. Fork Mountain Formation
8a
Composite magmatic arc and other magmatic rocks
Mainly Lower to Middle Ordovician metamagmatic rocks and associated metaclastic
rocks of the Chopawamsic volcanic arc. Chopawamsic Formation
8a_INT_FELSIC
rocks of the Chopawamsic volcanic arc. Intrusive rocks (felsic). Chopawamsic
8a_INT_MAFIC
rocks of the Chopawamsic volcanic arc. Intrusive rocks (mafic). Chopawamsic
8a_VOL_FELSIC
rocks of the Chopawamsic volcanic arc. Volcanic rocks (felsic). Chopawamsic
8b
Other metamagmatic rocks and associated metaclastic rocks of rift,
magmatic-arc, or oceanic affinity. Dadeville Complex
8b_INT_FELSIC
magmatic-arc, or oceanic affinity. Intrusive rocks (felsic). Dadeville Complex
8b_UMAFIC_OPH
magmatic-arc, or oceanic affinity. Ultramafic components of an ophiolite and
areas of isolated ultramafic and metaultramafic bodies. Dadeville Complex
8b_VOL_FELSIC
magmatic-arc, or oceanic affinity. Volcanic rocks (felsic). Dadeville Complex
8b_VOL_MAFIC
magmatic-arc, or oceanic affinity. Volcanic rocks (mafic). Dadeville Complex
9
Neoproterozoic to Lower Paleozoic mainly clastic metasedimentary rocks, schist
and gneiss locally associated with amphibolite and meta-ultramafic rocks.
Separated from unit 7 by a generally closer spatial relationship with unit 8a,
more prevalent migmatization, no direct association with ca. 1 Ga basement, the
lack of eclogite, and distinct structural style. Unnamed gneiss and schist of
the Six Mile Nappe
9_SHEAR
lack of eclogite, and distinct structural style. Shear zone. Unnamed gneiss and
schist of the Six Mile Nappe
9_UMAFIC_OPH
lack of eclogite, and distinct structural style. Ultramafic components of an
ophiolite and areas of isolated ultramafic and metaultramafic bodies. Unnamed
gneiss and schist of the Six Mile Nappe
ARBITRARY
Arcs used to close geological polygons
COASTAL_PLAIN
Coastal plain - internal polygons
DEFINED
Geological boundary
FAULT
Undefined fault
INLIER
Inlier - internal polygons
LIMIT_MAPPING
Limit of mapping
MELANGE
Mélange and broken formation
NORMAL_FAULT
Normal fault
STRIKE_SLIP
Strike-slip (arrows indicate relative movement)
STRUCTURAL
An arc used to close a geological polygon along a linear feature
SUB_DEFINED
Submerged geological boundaries
THRUST_FAULT
Thrust fault