The Geologic History
of New York State
The Acadian Orogeny
NE
SW
Helderberg Escarpment
Niagara Escarpment
Tug Hill Plateau
Adirondack Dome
SW
NE
Devonian Strata
Helderberg Escarpment
Helderberg Escarpment John Boyd Thatcher State Park
Lower Devonian - Coeymans
Fm.
Limestone
Lower Devonian - Manlius Fm.
Limestone
Upper Silurian - Rondout Fm.
Dolostone
Algal mat laminae - tidal flat deposits in the Manlius limestone
Lower Devonian
Coeymans Limestone
Lower Devonian coral reefs
Onondaga limestone,
Leroy, NY
Devonian seascape
Middle Devonian Hamilton Group
Shales and Siltstones
Middle Devonian Hamilton Group
Shales and Siltstones
Middle Devonian Hamilton Group
Brachiopod and Nautiloid
Middle Devonian Hamilton Group
Pelecypod
Middle Devonian Hamilton Group
Trilobite
Devonian Strata
Catskill Mts.
Catskill Mountains
horizontal strata
Catskill Group
River channel sandstone
Flood plain redbeds
Upper Devonian
Evolution of seed plants, trees, and forests
Gilboa fossil forest tree stumps, Catskills
Wattieza attached to Eospermatopteris
Devonian Strata
Letchworth Gorge
Letchworth Gorge, western New York
Upper Devonian sandstones,
siltstones, and shales
Letchworth Gorge
Western New York
regression
Simplified mid-Paleozoic Stratigraphy of New York
Upper
Devonian
Terrestrial
Active
Margin
Nearshore
Middle
Devonian
transgression
Catskill Group
Hamilton Group
Basin
Lower
Devonian
Silurian
Shallow Water
Coeymans - Onondaga
Manlius - Limestones
Tidal Flat
Rondout
Carbonates
Passive
Margin
Acadian Orogeny
• Middle - Upper Devonian
• Collision of N.Am with Avalonia (continental
fragment associated with Baltica (northern Europe).
• Rising Acadian Mountains to the east create a
deepening foreland basin in New York.
• Erosion of the Acadian Mountains fills in the basin
with a thick sequence of clastic sediments.
• Catskill Clastic Wedge
Middle Devonian 390 Ma
Devonian Strata
A’
A
Catskill clastic wedge - a filled-in foreland basin
A’
A
Evidence for the Acadian Orogeny
• Deposition of shale, siltstone, sandstone,
conglomerate - Catskill Delta.
• Devonian-age metamorphism in New England and
Virginia.
• Regions of pre-Devonian rock in New England with
European fossils (exotic, accreted terrains).
0 Ma
Phanerozoic
Modern Geologic Time Scale
C
M
P
Neogene
Tertiary
Pleistocene
Paleogene
Cenozoic
Proterozoic
Pliocene
Miocene
Oligocene
Eocene
Paleocene
Cretaceous
Mesozoic
2500 Ma
Holocene
Quat.
540 Ma
Jurassic
Triassic
Archean
3800 Ma
Carb.
Paleozoic
Permian
Pennsylvanian
Mississippian
Devonian
Silurian
Ordovician
Cambrian
Ma
0
.01
1.6
5
23
35
57
65
146
208
245
290
323
360
408
439
510
540
Hadean
4600 Ma
Quat. = Quaternary
Carb. = Carboniferous
Acadian Orogeny
Passive margin
Taconic Orogeny
Passive margin
Mississippian Period
• Few Mississippian age rocks preserved in NY.
• Deposition of limestone alternating with nearshore
shale and shoreline sandstones across much of
eastern North America.
• Passive margin conditions after erosion of Acadian
mountains.
Pennsylvanian Period
• Alleghenian Orogeny
• Collision of N.Am with Africa.
• Part of the assembly of Pangea.
• Not preserved in New York State, except for some
possible Alleghenian folds in older rock strata.
• Age of coal-forming swamps - hot, humid
conditions across Europe and Eastern North
America.
Evidence for the Alleghenian Orogeny
• Little evidence in New York.
• Foreland basin filled with clastic sediments - Ohio,
West Virginia, Kentucky, Tennessee.
• Folding and thrust faulting of pre-Permian strata
from Pennsylvania to Georgia.
• Pennsylvanian metamorphism east of folded rock.
Coastal
Plain
Blue Ridge
Plateau
Miss.-Penn. Sandstone /
shale
Valley and Ridge
Prot. - Miss. folded and thrust
faulted sedimentary rock
Piedmont
Paleozoic
metamorphic rock
Coastal
Plain
Blue Ridge
Plateau
Foreland basin filled with sediments
eroded from east.
Valley and Ridge
Slices of crust shoved
westward by collision.
Piedmont
Deeply buried roots of
the Alleghenian
mountain range.
Folds and thrust fault in Lower Devonian carbonates, Catskill Front
Mmmm….
Fresh
outcrop….
Carboniferous Sea Level
Cycles
• High amplitude
transgression-regression
cycles.
• Cyclothems: repeating
deposits alternating between
marine and terrestrial
deposition.
• Coal swamps formed during
beginning of transgression.
• Coals flooded by marine
waters.
• Thick sandstone layers
deposited during regression.
coal
sideritic silty shales
regressive limestone
core shale
transgressive limestone
Middle Pennsylvanian marine interval
0 Ma
Phanerozoic
Modern Geologic Time Scale
C
M
P
Neogene
Tertiary
Proterozoic
Pliocene
Miocene
Oligocene
Eocene
Paleocene
Cretaceous
Mesozoic
2500 Ma
Pleistocene
Paleogene
Cenozoic
Grenville
Orogeny
Holocene
Quat.
540 Ma
Jurassic
Triassic
Archean
3800 Ma
Carb.
Paleozoic
Permian
Pennsylvanian
Mississippian
Devonian
Silurian
Ordovician
Cambrian
Ma
0
.01
1.6
5
23
35
57
65
146
208
245
290
323
360
408
439
510
540
Hadean
erosion
Alleghenian Orogeny
Passive margin
Acadian Orogeny
Passive margin
Taconic Orogeny
Passive margin
Quat. = Quaternary
Carb. = Carboniferous
4600 Ma
Permian Period
• No Permian rock preserved in New York.
• Assembly of Pangea completed.
• Sea floor spreading stops - worldwide regression.
• Global climate is arid to seasonally wet.
• Massive volcanic eruptions in Siberia.
• Permian ends with largest mass extinction ever - up
to 95% of all species go extinct over several million
years.
• Triassic begins with a world depleted in species.