histo Flashcards
in North America, made up of smaller units delineated by their ages and structural trends
Canadian shield
belts are linear, syncline-like bodies
of rock found within much more extensive granite-gneiss
complexes
Archean greenstone
Ideal greenstone belts
consist of two lower units of mostly
igneous rocks and an upper sedimentary unit. They probably formed in several settings, including back-arc marginal
basins and intracontinental rifts
only known Archean fossils
of single-celled,
prokaryotic bacteria such as blue-green algae, but chemical compounds in some Archean rocks may indicate the
presence of archaea
formed by the activities of photosynthesizing bacteria are found in rocks as much as 3.5 billion
years old
Stromatolites
Archean mineral resources
gold, chrome, zinc,
copper, and nickel.
the most widespread Archean-age rocks
Granite-gneiss complexes
greenstone belts is not fully resolved, but
many geologists think that some of them formed in
backarc marginal basins
Age of most greenstone
belts, North America
Neoarchean
Oldest well-documented
stromatolites
Mesoarchean
Origin of continental crust, Possible stromatolites
Paleoarchean
Well-preserved greenstone
belts, South Africa
boundary of eoarchean and paleoarchean
Isua greenstone belt, Greenland
Chemical evidence
for life
Eoarchean
Acasta Gneiss, Canada
Eoarchean 4000 mya
-earth bombarded by meteorites and comets
-Oldest meteorites and
moon rocks
-Detrital zircons, Australia
-Origin of Earth’s moon
Eoarchean
consisting mostly of North America and
Greenland
Laurentia
Paleoproterozoic collisions between Archean cratons
formed larger cratons that served as nuclei, around
which crust accreted. One large landmass so formed
was
Laurentia
important events in the
evolution of Laurentia.
Paleoproterozoic amalgamation of cratons, followed by
Mesoproterozoic igneous activity, the Grenville orogeny,
and the Midcontinent rift
first well documented from the Neoarchean
and Paleoproterozoic, indicating that a plate tectonic style similar to that operating now had become
established
Ophiolite sequences marking convergent plate boundaries
common by Proterozoic time
Sandstone-carbonate-shale assemblages deposited on passive continental margins w
assembled between 1.3 and
1.0 billion years ago, fragmented, and then reassembled to
form Pannotia about 650 million years ago, which began
fragmenting about 550 million years ago
e supercontinent Rodinia
Photosynthesis continued to release free oxygen into the
atmosphere, which became increasingly rich in oxygen
through the
e Proterozoic.
Fully 92% of Earth’s iron ore deposits in the form of
banded iron formations were deposited between
2.5 and
2.0 billion years ago.
proof Earth’s atmosphere had enough
free oxygen for oxidation of iron compounds
Widespread continental red beds dating from 1.8 billion
years ag
they were probably present by
1.2 billion years ago. Endosymbiosis is a widely accepted
theory for their origin
Proterozoic organisms are singlecelled prokaryotes (bacteria).When eukaryotic cells first
appeared is uncertain
The oldest known multicelled organisms are might date back to the
Paleoproterozoic.
algae
Most of the world’s iron ore production is from
Proterozoic banded iron formations
One type of Proterozoic rock that indicates some free
oxygen was present in the atmosphere is
continental red beds
The oldest known animal fossils are found in the
fauna of Australia
Ediacaran
The Mesoproterozoic of Laurentia was a time of
igneous activity unrelated
to orogenic activity;
Origin and
fragmentation
of Pannotia
Rodinia fragments
Glaciation
Oldest worm
burrows
Wormlike fossils; China
Ediacaran faunas
Neoproterozoic
Midcontinent rift
Grenville
orogeny
Rodinia
forms
Acritarchs appear
Increase in size
and diversity of
micro-fossils
Mesoproterozoic
as a long-lived Mesoproterozoic mountain-building event associated with the assembly of the supercontinent Rodinia. Its record is a prominent orogenic belt which spans a significant portion of the North American continent, from Labrador to Mexico, as well as to Scotland.
greenville orogeny
Laurentia grows by
accretion along its
southern and
eastern margins
vboundary between Mesoproterozoic and Paleoproterozoic
Paleoproterozoic
amalgamation
of Archean cratons
oldest wellpreserved
ophiolite
Oldest red
beds
Carbonaceous impressions, China—possible
multi-celled algae
Oldest known eukaryotes—Negaunee Iron
Formation, Michigan
Stromatolites become widespread
Deposition of BIFs
Glaciation
Paleoproterozoic
Late Neoarchean
deformation
Single-celled prokaryotes
Neoarchean
is a largescale (greater than supergroup) lithostratigraphic unit representing a major transgressive–regressive cycle bounded
by craton-wide unconformities T e transgressive phase, which is usually covered by younger sediments, commonly is well preserved, whereas the regressive
phase of each sequence is marked by an unconformity.
cratonic sequence
record the first major transgression onto
the North American craton (Figure 10.3). During the
Neoproterozoic and Early Cambrian, deposition of marine sediments was limited to the passive shelf areas of the
Appalachian and Cordilleran borders of the craton.
e Sauk Sequence
with a major transgression onto the craton. This transgressing sea deposited clean, well-sorted quartz sands over
most of the craton sandstones is the St. Peter Sandstone, an almost-pure
quartz sandstone used in manufacturing glass. It occurs
throughout much of the midcontinent and resulted from
numerous cycles of weathering and erosion of Proterozoic and Cambrian sandstones deposited during the Sauk
transgression
The Tippecanoe Sequence
The first skeletal builders of reef-like structure
archaeocyathids
Beginning with the subduction of
the Iapetus plate beneath Laurentia (an oceanic–continental
convergent plate boundary), the Appalachian mobile belt
was born (Figure 10.13b). T e resulting
Taconic orogeny—
final piece of evidence for the Taconic orogeny is
the development of a large an extensive accumulation of mostly detrital sediments deposited adjacent
to an uplif ed area.
clastic wedge,
The clastic
wedge resulting from the erosion of the Taconic Highlands is referred to as the
Queenston Delta
, plate movements resulted
in a changing global geography. Gondwana moved southward and began to cross the South Pole as indicated by
Upper Ordovician tillite deposits; the microcontinent Avalonia separated from Gondwana during the Early Ordovician,
and collided with Baltica during the Late Ordovician–Early
Silurian; Baltica, along with the newly attached Avalonia
moved northwestward relative to Laurentia and collided
with it to form Laurasia during the Silurian
During the Ordovician and Silurian
the first major marine transgression onto the craton resulted in deposition of the
covered the craton except for
parts of the Canadian shield and the Transcontinental
Arch, a series of large, northeast–southwest trending
islands
Sauk Sequence
Sauk Sea
began with deposition of
extensive sandstone over the exposed and eroded Sauk
landscape.
, extensive carbonate deposition took place. In addition, large barrier reefs
enclosed basins, resulting in evaporite deposition within
these basins
Tippecanoe Sequence
The eastern edge of North America was a stable carbonate
platform during Sauk time. During Tippecanoe time, an
oceanic–continental convergent plate boundary formed,
resulting in the
e Taconic orogeny, the first of three major
orogenies to affect the Appalachian mobile belt.
shed sediments into
the western epeiric sea, producing a clastic wedge that
geologists call the Queenston Delta.
he newly formed Taconic Highlands
Early Paleozoic-age rocks contain a variety of mineral
resources, including
g building stone, limestone for cement,
silica sand, hydrocarbons, evaporites, and iron ore.
During which sequence did the eastern margin of Laurentia change from a passive plate margin to an active
plate margin?
tippecanoe
A major transgressive–regressive cycle bounded by
craton-wide unconformities is a(n)
cratonic sequence
An elongated area marking the site of mountain building
is a(n)
mobile belt
The ocean separating Laurentia from Baltica is called the
lapetus sea
Which mobile belt is located along the eastern side of
North America?
Appalachian
During deposition of the Sauk Sequence, the only area
above sea level besides the Transcontinental Arch was the
Canadian shield;
The vertical sequence of the Tapeats Sandstone, Bright
Angel Shale, and Muav Limestone represents
time transgressive formations;
craton : Extensive
barrier
reefs and
evaporites
common
appalachian: acadian orogeny
caledonian orogeny
First jawed
fish evolve
Early land
plants—
seedless
vascular
plants
Silurian
Queenston
Delta clastic
wedge
Transgression
of Tippecanoe
Sea
Regression
exposing large
areas to erosion
Taconic
orogeny
Continental
glaciation in
Southern
Hemisphere
Extinction of
many marine
invertebrates
near end of
Ordovician
Plants move
to land?
Continental
glaciation in
Southern
Hemisphere
Table 10.1
Summary of Early Paleozoic Geologic and Evolutionary Events
Major adaptive
radiation of all
invertebrate
groups
Ordovician
tippecanoe
silurian and ordovician
Canadian shield
and Transcontinental Arch
only areas
above sea level
Transgression
of Sauk Sea
Many
trilobites
become
extinct near
end of
Cambrian
Earliest
vertebrates—
jawless fish
evolve
cambrian
sauk
cambrian-ordovician
boundary between the Tippecanoe Sequence and the
overlying is marked by a major unconformity. As the
Kaskaskia Sea transgressed over the low-relief landscape of
the craton, most basal beds deposited consisted of clean,
well-sorted quartz sandstones. A good example is the
Oriskany Sandstone of New York and Pennsylvania and
its lateral equivalents
Kaskaskia Sequence
T e boundary between the Tippecanoe Sequen
Rising majestically 50 to 100 meters above
the surrounding plains, the Great Barrier
Reef of the Canning Basin, Australia, is
one of the largest and most spectacularly
exposed fossil reef complexes in the world
(Figure 1). This barrier reef complex developed during the Middle and Late Devonian
Period, when a tropical epeiric sea covered
the
The Canning Basin, Australia—A Devonian
Great Barrier Reef
includes rocks deposited during
the Pennsylvanian through Early Jurassic. In this chapter,
however, we are concerned only with the Paleozoic rocks
of
The Absaroka Sequen
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.
Ouachita Mobile Belt T
econstruction 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
Antler Orogeny
stretches
along the western border of Baltica and includes the
present-day countries of Scotland, Ireland, and Norway
(see Figure 10.2c). During the Middle Ordovician, subduction along the boundary between the Iapetus plate and Baltica
(Europe) began, forming a mirror image of the convergent
plate boundary off the east coast of Laurentia (North America)
Caledonian Orogeny
occurred during the Late Silurian and Early
Devonian with the formation of a mountain range along the
western margin of Baltica (see Figure 10.2c). Red-colored
sediments deposited along the front of the Caledonian
Highlands formed a large clastic wedge known as the Old
Red Sandstone
The red beds of the Catskill Delta
have a European counterpart in the Devonian Old Red
Sandstone of the British Isles (Figure 11.17). The Old Red
Sandstone was a Devonian clastic wedge that grew eastward from the Caledonian Highlands onto the Baltica craton. The Old Red Sandstone, just like its North American
Catskill counterpart, contains numerous fossils of freshwater fish, early amphibians, and land plan
The Old Red Sandstone Th
thick clastic wedge named
for the Catskill Mountains in upstate New York, where it is
well exposed
e Catskill Delta,
- During the Late Paleozoic, Baltica and Laurentia collided,
forming
Laurasia.
Siberia and Kazakhstania collided and
finally were sutured to Laurasia. Gondwana moved over
the South Pole and experienced several glacial–interglacial
periods, resulting in global sea level changes and transgressions and regressions along the low-lying craton margins
Late Paleozoic
underwent a series of collisions beginning in the Carboniferous. During the
Permian, the formation of Pangaea was completed.
Surrounding the supercontinent was the global ocean,
Panthalassa
Laurasia and Gondwana
The Late Paleozoic history of the North American craton
can be deciphered from the rocks of the
Kaskaskia and
Absaroka sequences.
deposited on the exposed Tippecanoe surface consisted
either of sandstones derived from the eroding Taconic
Highlands, or of carbonate rocks.
basal beds of the Kaskaskia Sequence
Most of the Kaskaskia Sequence is dominated by
carbonates and associated evaporites. T
a time of major reef building in western Canada, southern
England, Belgium, Australia, and Russia
devonian period
deposited over large areas of the craton during the Late Devonian and Early
Mississippian
Widespread black shales
The Mississippian Period was dominated, for the most
part, by
carbonate deposition.
caused by advancing and retreating Gondwanan ice sheets, over the
low-lying North American craton, resulted in cyclothems
and the formation of coals during the Pennsylvanian
Period.
* Crato
Transgressions and regressions
occurred during the Pennsylvanian Period and
resulted in thick nonmarine detrital sediments and evaporites being deposited in the intervening basins
Cratonic mountain building, specifically the Ancestral
Rock
Absaroka Sea occupied a narrow zone of the south–central craton. Here, several large
reefs and associated evaporites developed
Early Permian, t
this epeiric sea had retreated from
the craton
Permian Period
the site of the Antler
orogeny, a minor Devonian orogeny during which deepwater sediments were thrust eastward over shallow-water
sediments
The Cordilleran mobile belt
mountain
building occurred in the Ouachita mobile belt. This tectonic activity was partly responsible for the cratonic uplift
in the southwest, resulting in the Ancestral Rockies.
During the Pennsylvanian and Early Permian
orogenies were all part of the global tectonic activity that
resulted from the assembly of Panga
The Caledonian, Acadian, Hercynian, and Alleghenian
a, numerous microplates and terranes, such as Avalonia, Iberia–Armorica, and Perunica,
existed and played an important role in forming Pangaea.
Paleozoic Era
Late Paleozoic-age rocks contain a variety of mineral resources, including
g petroleum, coal, evaporites, silica sand,
lead, zinc, and other metallic deposits.
Deserts, evaporites, and
continental red beds in
southwestern United
States.
Extensive reefs in
Texas area
Formation of Pangaea
Allegheny orogeny
Hercynian orogeny
Largest mass
extinction event
to affect the
invertebrates
Many vertebrates
go extinct
Gymnosperms
diverse and
abundant
Permian
Coal swamps common
Formation of Ancestral
Rockies
Transgression of
Absaroka Sea
Ouachita
orogeny
Continental
glaciation in
Southern
Hemisphere
Amphibians
diverse and
abundant
Abundant coal
swamps with
seedless vascular
plants
Pennsylvanian
Widespread black shales
Reptiles evolve
Gymnosperms
evolve
Mississippian
Antler orogeny
Extensive barrier reef
formation in Western
Canada
Transgression of
Kaskaskia Sea
Catskill Delta clastic
wedge
Widespread black shales
Acadian orogeny
Old Red Sandstone
clastic wedge in
British Isles
Caledonian orogeny
Extinction of
many reef-building
invertebrates
Amphibians evolve
All major groups
of fish present—
Age of Fish
Early land
plants–seedless
vascular plants
Devonian
tippecanoe
devonian
kaskaskia
devonian and missippian
absaroka
pennsylvanian and permian
Which of the following resulted from intracratonic
deformation?
Ancestral Rockies;
The Catskill Delta clastic wedge resulted from weathering and erosion of the __________ highland
Acadian;
During which Paleozoic cratonic sequence were
cyclothems common?
Absaroka;
During which period did extensive continental glaciation
of the Gondwana continent occur?
ordovician
Which was the first Paleozoic orogeny to occur in the
Cordilleran mobile belt?
Antler;
In what two areas can Late Paleozoic barrier reefs be found?
Western Canada and Texas–New
Mexico;
The Ancestral Rockies formed during which geologic
period?
Pennsylvanian
The economically valuable deposit in a cyclothem is
coal
Which orogeny was not involved in the closing of the
Iapetus Ocean?
antler