Late Paleozoic

Formation of Supercontinent Pangea

 Laurentia and Baltica collided to form Laurasia (Caledonian orogeny)

Silurian
 Laurasia and Gondwana collided (Acadian orogeny) Devonian
 Antler orogeny in the Cordilleran region
 Laurasia and Siberia collided (Ellesmere orogeny) at the northern part
of Laurasia Devonian
 Baltica and Siberia collided forming the Ural Mountains

Devonian:

Paleogeography of the World

Figure 2 (Devonian) Figure 1 (For the Early Carboniferous Period)

Figure 3 (For the Late Carboniferous Period) Figure 4 (For the Late Permian Period)

Paleoclimate:
 Devonian

o Uniform warm climate

  Carboniferous

o Gondwana moved over the South pole, resulting in continental

glatiation (tillite)

o Wide spreaded coal deposites

 Permian

o Supercontinent, extreme climate conditions

Average global temperatures in the Early Carboniferous Period were hot-

approximately 22° C (72° F). However, after cooling during the Middle
Carboniferous the average temperature became about 12° C (54° F).

carbon dioxide (CO2) in the Early Carboniferous Period was approximately

1500 ppm but by the Middle Carboniferous had declined to about 350 ppm –

Earth's atmosphere today contains about 370 ppm CO2 (0.037%).

In the last 600 million years of Earth's history only the Carboniferous Period
and our present age, the Quaternary Period, have witnessed CO2 levels less
than 400 ppm.

Late
Paleozoic oxygen peak:

Long-term background
(Cambrian → early Devonian,
~540–400 Ma)
Rise to the peak (Middle Devonian → Late Carboniferous, ~400–300 Ma)

The apex (Late Carboniferous–Early Permian, ~320–275 Ma) (Estimated O₂

peaks between 30 % and 35 %

Decline (Mid-Permian → Early Triassic, ~275–240 Ma)

Mesozoic–Cenozoic fluctuations (240 Ma → present)

Take-away:
The Late Paleozoic oxygen spike was driven primarily by the explosive
colonization of land by deep-rooting, woody plants that outpaced microbial
decay, tipping Earth’s redox balance toward unusually oxygen-rich air—an
environmental pulse that reshaped wildfire regimes, animal physiology, and
ultimately set the stage for the largest mass extinction as conditions
reversed.

Protists (fusulinid forams)

Late Paleozoic cratonic sequences Kaskaskia (Devonian-

Pennsylvanian)

 Starts with major unconformity

 Quartz sandstone (Oriskany sandstone)
o source area is the Taconi highland
 Carbonate rocks as result of transgression
o Reef , evaporite facies (Canada Williston basin)
 Peak Transgression (Black Shale)
  Regression formation of carbonates
 Unconformity

The boundary between Tippeccanoe and Kaskaskia sequence is marked by a

major unconformity.

During the transgression of the Kaskaskia

seawater in the early Devonian clean mature
sandstone covered much of the craton as basal
deposits (Oriskany sandstone, NewYork,
Pennsylvania).

Their source area was the Appalachian mobile

belt which is contained older sandstone facies.

The Oriskany is a very important rock formation

commercially. In areas encountered at depth, it
is an important natural gas bearing formation.
At Berkeley Springs/Hancock, it has been
quarried for many years as a glass sand.

The Oriskany is a remarkably pure white quartz Figure 5 (Oriskany)

sandstone that often can be easily crumbled where it has been exposed to
weathering. That is because the cement that holds
the quartz grains together is predominantly calcium
carbonate.

After the sandstone basal sediment, the majority of

kaskaskian rocks are carbonates including reefs, and
associated evaporite deposits. In many other areas of
the world same kind of sediments could be found.
(England, Belgium, Central Europe, Australia, Russia).

Reefs in Western Canada

Middle and Late Devonian reefs are very important in

Western Canada (huge oil reservoir). By the middle Devonian a huge barrier
reef has developed and the lagoon areas behind the reef became restricted
and lots of evaporates formed.
Black shale = OCEAN IS STRATIFIED)

During Late Devonian the character of the

sediment has changed from shallow water
carbonates to black shale and coarser detrital
rocks. The source of these sediments were
the mountains formed by the Acadian
orogeny in northern America.

In the Eastern US this black shale is called

Chattanooga shale. These shale deposits are
the best developed along the Appalachian
mobil belt to the Mississippi valley, they can be found
elsewhere also.

This shale usually is thin bedded, non calcareous,

less than 10 m thick, and rich in land plants. They
sometimes are bitominous, containing mostly
degraded algal material. (Source material for oil!)

Presence of black shale indicate anaerobic bottom

condition, reduced supply of coarse sediment and
high organic productivity of the overlying
oxygenated water layer.

The Chattanooga shale in Tennessee contains a

stratum, the Gassaway member, about 5 meters
thick whose average content of uranium is about 70
grams per metric ton (Kerr, 1955). With a density of
2.5 metric tons per cubic meter, this would amount to about 175 grams of
uranium per cubic meter, or to 875 grams per square meter for the total
thickness of the member.

Late Kaskaskia

 As regression started carbonate formation returned

o crinoideal, oolitic limestone, dolomite
 During global regression, sandstone deposition returned(good oil
reservoar in Illinois basin).

Late Paleozoic cratonic sequences

2. Absaroka (Pennsylvanian to Jurassic)

 Uppermost Mississippian-Jurassic; unconformity between Kaskaskia

and Absaroka divides Carboniferous
into Mississippian-Pennsylvanian
 By this time as the result of plate
tectonic developments huge foreland
basin covers most of the Appalachian
area

Foreland basin:

Sedimentation in the foreland basin Figure 6 (Absaroka geography)

 East side
o fast subsidence
o cyclothers
 West side
o gentle sloping
o carbonate deposition
 Cyclotherms
o Alternating marine-nonmarine
deltaic strata as the result of
sea level changes
 Cyclothems and
Coal:

 Regression

Reversed
the

sequence
 Oscillating glaciers led to changes in
sea level
Cratonic uplift ancestral Rockies

 As a result of multiple collision, during the Late Absaroka uplifting

happened in the southern part of North America.
 Colorado Spring red sandstone

Late Absaroka:

 In the basins around the ancestral

Rockies lots of sediment was
depositing
 One of the best example is the
Paradox basin in the four corner
region (Arizona, New Mexico,
Utah, Colorado
 The Paradox basin and the four
corners region (Arizona, New
Mexico, Colorado, Utah) was covered by the Absaroka sea.
 During the Middle Pennsylvanian thick cyclical deposits of gypsum,
anhydrite and salt formed in the central basin area.
 Fossiliferous and oolitic limestones were deposited around the
perimeter, with patch and barrier reefs growing along the western
margin, further restricting the central basin. (oil reservoar).
 During the Late Pennsylvanian, the whole Paradox basin was filled, by
arkosic red sandstone.

Paradox Basin Study

The Paradox Basin, which extends from

Utah into portions of Colorado and
Arizona, contains more than 75 small
oil fields, each capable of producing 2
to 10 million barrels of oil. But
variations in the reservoirs of these
fields prevent recovery of up to 75 percent of that resource, using
conventional extraction methods.

Late regression of the absaroka sea:

 The Sea is restricted to west Texas, New Mexico, forming a complex of

lagoonal, reef, openshelf environment
 Guadalupe Mountains

Mobil Belts

 Cordillerran
o Antler orogeny (island arc)
 Ouachita
o Texas, Arkansas
o Volcanic arc to craton collision
o rapid sedimentation in the
surraunding basins
 Appalachian mobile belt
o Caledonian orogeny (Silurian-
Devonian)
o Acadian (Devonian)
o Hercynian Alleghany
(Mississippian, Permian)

Catskill Delta Clastic Wedge

Area of collision between Laurentia and Baltica

o The Catskill Delta clastic wedge

o and the Old Red Sand-stone
o are bilaterally symmetrical
o and derived their sediments
o from the Acadian and Caledonian
Highlands

Mineral resources of the Late

Paleozoic
o Petroleum and natural gas
o from Devonian to Permian rocks (Michigan basin, Illinois basin,
Williston basin of Montana, South Dakota)
o Permian reefs in the western US. Texas also important.
Phanerozoic mega-petroleum systems

Hydrocarbons are irregularly distributed throughout the crust and the

petroleum reserves of a few geologic basins and provinces far surpass all
others (Brooks, 1990).

In fact, approximately 80% of the world's currently known petroleum

deposits are located in ten geologic provinces (Table 2).

The Arabian-Iranian province by far

contains the lion’s share of
conventional hydrocarbon reserves,
with roughly three times the amount
of the next largest province. As in
the case of major hydrocarbon source
intervals, the uneven distribution of
oil and gas can be related to the
timing and confluence of geologic
cycles and secular changes.

Coal:

o Pennsylvanian
o Appalachians and mid western
US.
o (Bituminous coal more than
80% C)
o Some of the coal is
metamorphosed and become
antracite 98%C.

Evaporite

o Zechstein evaporites in Europe

o Delaware, New Mexico
o Michigan

Quartz sandstone

o West Virginia, Maryland, Pennsylvania.

Limestone

o Cement, and it is found everywhere

Metallic

o Copper, gold silver

o Mississippi type lead and zinc deposits in Missouri, Virginia, Tenesse.

Life of the Late Paleozoic

A Cephalopode at the center. Behind, a

straight-shelled cephalopod. At front left, the
trilobite Phacops is moving near a cluster of
brachiopods.

Vertebrates in marine environment

The Devonian has been called the "Age of the

Fish" because of the tremendous diversity of
fish groups that evolved during this period.
Small, jawless, and finless fish were the
earliest vertebrates. They were filter feeders, but
probably were also able to move water through their
gills by muscular action.

Placoderms

The first jawed fish were the Placoderms. They were

armored with heavy plates and had strong jaws and paired pectoral and
pelvic fins. Paired fins allow fish to balance and to maneuver well in water,
which facilitate both predation and escape.
 Late Paleozoic Life (Plants)

vascular plants

o Drepanophycus , a middle Devonian lycophyte. Note the

numerous microphyll leaves
o Penn. lowland forest
o Lepidodendron (a) and
o Sigillaria (b) Lycopods
o Sphenopsid (horsetail rush)
o Sphenopsid (Calamities)

Late Paleozoic Life The Amniotic Egg

The crossopterygian fish are regarded as ancestors
of early amphibians. Extinct crossopterygians had
strong fins, lungs, and a streamlined body capable
of swimming as well as traveling short distances out
of water.

Late Paleozoic Life (Reptile Evolution – Pelycosaurs)

o evolved from the protorothyrids during the

Pennsylvanian
o the dominant reptile group by the Early
Permian
o evolved into a diverse assemblage

Permian mass extinction

About 250 million years ago, more than 90% of all

species on Earth mysteriously perished during a mass
extinction, perhaps within just a few thousand years.
Trilobites became extinct; coral, bryozoan, and
brachiopod species diminished. Land plants and animals
were also impacted; amphibian species dwindled and
fungi dominated some ecosystems. The cause of the
“Great Dying” is not yet known, although many scientists
attribute the catastrophe to major environmental
changes, perhaps involving reorganization of ocean
circulation or massive volcanism.