Late Paleozoic Earth History

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Late Paleozoic Earth History

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Title: Late Paleozoic Earth History

1
Chapter 11
Late Paleozoic Earth History
2
Tully Monster

Tullimonstrum gregarium, also known as the Tully
Monster is Illinoiss official state fossil
Specimen from Pensylvanian rocks, Mazon Creek
Locality, Illinois

Reconstruction of the Tully Monster
about 30 cm long

3
Mazon Creek Fossils

Approximately 300 million years ago
in the region of present-day Illinois,
sluggish rivers flowed southwestward through
swamps,
and built large deltas that extended outward into
a subtropical shallow sea
These rivers deposited high quantities of mud
that entombed many of the plants and animals
living in the area
Rapid burial
and the formation of ironstone concretions
preserved many of the plants and animals of the
area

4
Pennsylvanian Delta Organisms

During Pennsylvanian time, two major habitats
existed in northeastern Illinois
One was a swampy forested lowland of the
subaerial delta,
and the other was the shallow-marine environment
of the actively prograding delta
Living in the warm, shallow waters
of the delta front were numerous
cnidarians,
mollusks,
echinoderms,

arthropods,
worms,
and fish

5
Swampy Lowlands

The swampy lowlands surrounding the delta were
home to more than 400 plant species,
numerous insects,
including millipedes and centipedes, as well as
spiders
and other animals such as
scorpions and amphibians
In the ponds, lakes, and rivers were many
fish, shrimp, and ostracodes
Almost all of the plants were
seedless vascular plants,
typical of the kinds that lived in the
coal-forming swamps
during the Pennsylvanian Period

6
Late Paleozoic Paleogeography

The Late Paleozoic was a time of
continental collisions,
mountain building,
fluctuating seas levels,
and varied climates
Coals, evaporites, and tillites
testify to the variety of climatic conditions
experienced by the different continents during
the Late Paleozoic

7
The Devonian Period

During the Silurian,
Laurentia and Baltica collided along a convergent
plate boundary
to form the larger continent of Laurasia
This collision,
which closed the northern Iapetus Ocean,
is marked by the Caledonian orogeny
During the Devonian,
as the southern Iapetus Ocean narrowed
between Laurasia and Gondwana,
mountain building continued along the eastern
margin of Laurasia
with the Acadian orogeny

8
Paleogeography of the World

For the Late Devonian Period

9
Paleogeography of the World

For the Early Carboniferous Period

10
Paleogeography of the World

For the Late Carboniferous Period

11
Paleogeography of the World

For the Late Permian Period

12
The Kaskaskia Sequence

Middle Devonian-Middle Mississippian
The boundary with the Tippecanoe sequence is a a
major unconformit.
As the Kaskaskia Sea transgressed over the
craton, the basal beds consisted of clean,
well-sorted quartz sandstones

13
Oriskany Sandstone

A good example is the Oriskany Sandstone
of New York and Pennsylvania
and its lateral equivalents

14
Basal Kaskaskia Sandstones

Extent of the basal units of the Kaskaskia
sequence in the eastern and north-central
United States

15
Source Areas

The source areas for the basal Kaskaskia
sandstones
were primarily the eroding highlands of the
Appalachian mobile belt area,
exhumed Cambrian and Ordovician sandstones
cropping out along the flanks of the Ozark Dome,
and exposures of the Canadian Shield in the
Wisconsin area

16
Devonian Period

Paleogeography of North America during the
Devonian Period

17
Kaskaskian Rocks

The majority of Kaskaskian rocks are
carbonates, including reefs, and associated
evaporite deposits

18
Major Reefs in Other Parts of the World

In many other parts of the world, such as
southern England,
Belgium,
Central Europe,
Australia,
and Russia,
the Middle and early Late Devonian epochs were
times of major reef building

19
Reef Development in Western Canada

The Middle and Late Devonian-age reefs of western
Canada
contain large reserves of petroleum
and have been widely studied from outcrops and in
the subsurface
These reefs began forming
as the Kaskaskia Sea transgressed southward
into Western Canada

20
Devonian Reef Complex

Reconstruction of the extensive Devonian Reef
complex of western Canada

These reefs controlled the regional facies of the
Devonian epeiric seas

21
Potash from Evaporites

More than half of the world's potash,
which is used in fertilizers,
comes from these Devonian evaporites
By the middle of the Late Devonian,
reef growth stopped in the western Canada region,
although non-reef carbonate deposition continued

22
Increased Detrital Deposition

Deposition of black shales
was brought on by the the Acadian orogeny

23
Widespread Black Shales

These Upper Devonian-Lower Mississippian black
shales are typically
noncalcareous,
thinly bedded,
and usually less than 10 m thick

24
Extent of Black Shales

The extent of the upper Devonian and Lower
Mississippian Chattanooga Shale and its
equivalent units
such as the Antrion Shale and the Albany Shale

25
New Albany Shale

Upper Devonian New Albany Shale,
Button Mold Knob Quarry, Kentucky

26
The Late Kaskaskia

Following deposition of the black shales,
carbonate sedimentation on the craton dominated
the remainder of the Mississippian Period

27
Mississippian Period

Paleogeography of North America during the
Mississippian Period

28
Mississippian Carbonates

These Mississippian carbonates display
cross-bedding, ripple marks, and well-sorted
fossil fragments,
all of which are indicative of a shallow-water
environment
Analogous features can be observed on the
present-day Bahama Banks
In addition, numerous small organic reefs
occurred throughout the craton during the
Mississippian
These were all much smaller than the large
barrier-reef complexes
that dominated the earlier Paleozoic seas

29
Regression of the Kaskaskia Sea

During the Late Mississippian regression
of the Kaskaskia Sea from the craton,
carbonate deposition was replaced
by vast quantities of detrital sediments

30
Cratonwide Unconformity

Prior to the end of the Mississippian,
the Kaskaskia Sea had retreated
to the craton margin,
once again exposing the craton
to widespread weathering and erosion
This resulted in a cratonwide unconformity
when the Absaroka Sea began Transgressing
back over the craton

31
The Absaroka Sequence

The Absaroka sequence
includes rocks deposited
during the latest Mississippian
through Early Jurassic
The extensive unconformity
separating the Kaskaskia and Absaroka sequences
essentially divides the strata
into the North American
Mississippian and Pennsylvanian systems

32
Pennsylvanian Period

Paleogeography of North America during the
Pennsylvanian Period

33
What Are Cyclothems?

A cyclical pattern of alternating marine and
nonmarine strata
is one of the characteristic features of
Pennsylvanian rocks
Such rhythmically repetitive sedimentary
sequences are known as cyclothems
They result from repeated alternations
of marine
and nonmarine environments,
usually in areas of low relief

34
Cyclothem

Columnar section of a complete cyclothem

35
Pennsylvanian Coal Bed

Pennsylvanian coal bed, West Virginia
part of a cyclothem

36
Coal-Forming Swamp

Reconstruction of the environment of a
Pennsylvanian coal-forming swamp

37
The Okefenokee Swamp

in Georgia, is a modern coal-forming environment,

similar to those occurring during the
Pennsylvanian Period
38
Ancestral Rockies

During the Late Absaroka (Pennsylvania),
the area of greatest deformation occurred in the
southwestern part of the North American craton
where a series of fault-bounded uplifted blocks
formed the Ancestral Rockies
Uplift of these mountains,
some of which were elevated more than 2 km along
near-vertical faults,
resulted in the erosion of the overlying
Paleozoic sediments
and exposure of the Precambrian igneous and
metamorphic basement rocks

39
Pennsylvanian Highlands

Location of the principal Pennsylvanian highland
areas and basins of the southwestern part of the
craton

40
Ancestral Rockies

Block diagram of the Ancestral Rockies, which
were elevated by faulting during the
Pennsylvanian Period

Erosion of these mountains produced
coarse red sediments
that were deposited in the adjacent basins

41
Red bed Sediment

As the Ancestral Rocky mountains eroded,
tremendous quantities of
coarse, red arkosic sand and conglomerate
were deposited in the surrounding basins
These sediments are preserved in many areas
including the rocks of the Garden of the Gods
near Colorado Springs
and at the Red Rocks Amphitheater near Morrison,
Colorado

42
Garden of the Gods

Storm-sky view of Garden of the Gods from Near
Hidden Inn, Colorado Springs, Colorado

43
Intracratonic Mountain Ranges

It is thought that the collision of Gondwana with
Laurasia produced great stresses in the
southwestern region of the North American craton
These crustal stresses were relieved by faulting
that resulted in uplift of cratonic blocks
and downwarp of adjacent basins,

44
The Late Absaroka

While the various intracratonic basins
were filling with sediment
during the Late Pennsylvanian,
the Absaroka Sea slowly began retreating from the
craton
During the Early Permian,
the Absaroka Sea occupied a narrow region
from Nebraska through west Texas

45
Permian Period

Paleogeography of North America during the
Permian Period

46
Middle Permian Absaroka Sea

By the Middle Permian,
the sea had retreated to west Texas
and southern New Mexico
The thick evaporite deposits
in Kansas and Oklahoma
provide evidence of the restricted nature of the
Absaroka Sea
during the Early and Middle Permian

47
Restricted Absaroka Sea

Three basins separated by two submerged platforms
formed during the Permian

48
Permian Reefs and Basins

Location of the west Texas Permian basins and
surrounding reefs

49
Massive Reefs

Massive reefs grew around the basin margins
while limestones, evaporites, and red beds were
deposited
in the lagoonal areas behind the reefs
As the barrier reefs grew and the passageways
between the basins became more restricted,
Late Permian evaporites gradually filled the
individual basins

50
Capitan Limestone Reef Reconstruction

Reconstruction of the Middle Permian Capitan
Limestone reef environment
Shown are brachiopods, corals, bryozoans and
large glass sponges

51
Capitan Limestone

Spectacular deposits representing the geologic
history of this region
can be seen today in the Guadalupe Mountains of
Texas and New Mexico
where the Capitan Limestone forms the caprock of
these mountains
By the end of the Permian Period,
the Absaroka Sea had retreated from the craton
exposing continental red beds
over most of the southwestern and eastern region

52
Antler orogeny at the Cordilleran Mobile belt

A collision between
this eastward-moving island arc
and the western border of the Laurasia
during the Late Devonian and early Mississippian,
produced in a highland area
This orogenic event,
the Antler orogeny,
caused by subduction and closure of a narrow
ocean basin

53
Antler Highlands

Reconstruction of the Cordilleran mobile belt
during the Early Mississippian

in which deep-water continental slope deposits

were thrust eastward
over shallow-water continental shelf carbonates
forming the Antler Highlands

54
Ouachita Mobile Belt

The Ouachita mobile belt
extends for approximately 2100 km
from the subsurface of Mississippi
to the Marathon region of Texas
Approximately 80 of the former mobile belt
is buried beneath a Mesozoic and Cenozoic
sedimentary cover
The two major exposed areas in this region are
the Ouachita Mountains of Oklahoma and Arkansas
and the Marathon Mountains of Texas

55
Beginning of the Ouachita Orogeny

During the Late Proterozoic to Early
Mississippian,
shallow-water detrital and carbonate sediments
deposited on a broad continental shelf,
while bedded cherts and shales accumulated in
deeper-water
Beginning in the Mississippian Period,
the region changed from a passive continental
margin to an active convergent plate boundary,
marking the beginning of the Ouachita orogeny

56
Ouachita Mobile Belt