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
Marine organisms are divided into four basic feeding
groups:
suspension feeders, which consume microscopic plants and animals as well as dissolved nutrients from water; herbivores, which are plant eaters;
carnivore-scavengers, which are meat eaters; and
sediment-deposit feeders, which ingest sediment and
extract nutrients from it.
The Cambrian invertebrate community was dominated
by three major groups
the trilobites, inarticulate brachiopods, and archaeocyathids. Little specialization existed
among the invertebrates, and most phyla were represented
by only a few species.
e contains one of the
finest examples of a well-preserved, soft-bodied biota in
the world.
e Middle Cambrian Burgess Shale
marked
the beginning of the dominance by the shelly fauna and the
start of large-scale reef building. The end of the Ordovician Period was a time of major extinction for many invertebrate phyla
Ordovician marine invertebrate community
times of diverse
faunas dominated by reef-building animals, whereas the
Carboniferous and Permian periods saw a great decline in
invertebrate diversity
e Silurian and Devonian period
Which group of planktonic invertebrates that were especially abundant during the Ordovician and Silurian periods are excellent guide fossil
Graptolites
What type of invertebrates dominated the Ordovician invertebrate community?
Epifaunal
benthic mobile suspension feeders
The earliest reef-like structures were constructed by
archaeocyathids
The age of the Burgess Shale is
Cambrian;
Largest mass
extinction event
to affect the
invertebrates
Therapsids and
pelycosaurs the most
abundant reptiles
Acanthodians,
placoderms, and
pelycosaurs become
extinct
Gymnosperms diverse
and abundant
Formation of Pangaea
Alleghenian orogeny
Hercynian orogeny
permian
Fusulinids diversify
Amphibians
abundant
and diverse
Coal swamps with flora
of seedless vascular plants
and gymnosperms
Coal-forming swamps
common
Formation of Ancestral Rockies
Continental glaciation in
Gondwana
Pennsylvanian
Crinoids, lacy
bryozoans, blastoids
become abundant
Renewed adaptive radiation following extinctions
of many reef-builders
Reptiles evolve
Gymnosperms appear
(may have evolved
during Late Devonian)
Ouachita orogeny
Widespread deposition of
black shale
Acadian orogeny
Antler orogeny
Widespread deposition of
black shale
Mississippian
Extinctions of many
reef-building
invertebrates near
end of Devonian
Reef building continues
Eurypterids abundant
Amphibians evolve
All major groups of
fish present—Age
of Fish
First seeds evolve
Seedless vascular plants
diversify
Widespread deposition of
black shale
Acadian orogeny
Antler orogeny
Devonian
Major reef building
Diversity of invertebrates
remains high
Ostracoderms common
Acanthodians, the first
jawed fish, fish evolve
early land plants—
seedless vascular plants
Caledonian orogeny
Extensive barrier reefs and
evaporites
Silurian
Extinctions of a
variety of marine
invertebrates near
end of Ordovician
Major adaptive
radiation of all
invertebrate groups
Suspension feeders
dominant
Ostracoderms
diversify
Plants move to land?
Continental glaciation in
Gondwana
Taconic orogeny
Ordovician
Many trilobites
become extinct near
end of Cambrian
Trilobites, brachiopods,
and archaeocyathids
are most abundant
Earliest vertebrates—
jawless fish called
ostracoderms
First Phanerozoic
transgression (Sauk)
onto North American
craton
Cambrian
characterized by a notochord, dorsal hollow
nerve cord, and gill slits. The earliest chordates were softbodied organisms that were rarely fossilized. Vertebrates
are a subphylum of the chordates.
Chordates
earliest known vertebrates with their first fossil occurrence in Upper Cambrian rocks. They have had
a long and varied history, including jawless and jawed
armored forms (ostracoderms and placoderms), cartilaginous forms, and bony forms. It is from the lobe-finned
fish that amphibians evolved.
Fish
The link between crossopterygian lobe-finned fish and
the earliest amphibians is convincing and includes a close
similarity of bone and tooth structures. However, new fossil discoveries show that the transition between the two
groups is more complicated than originally hypothesized,
and includes several intermediate forms
omg
evolved during the Late Devonian, with labyrinthodont amphibians becoming the dominant terrestrial
vertebrate animals during the Carboniferous.
Amphibians
marks the earliest fossil record
of reptiles. The evolution of an amniote egg was the
critical factor that allowed reptiles to completely
colonize the land.
The Late Mississippian
were the dominant reptiles during the Early
Permian, whereas therapsids dominated the landscape for
the rest of the Permian Period.
Pelycosaurs
earliest fossil record of land plants is from
Middle
to Upper Ordovician rocks. These plants were probably
small and bryophyte-like in their overall organization
were small, leafless
stalks with spore-producing structures on their tips.
From this simple beginning, plants evolved many of
the major structural features characteristic of today’s
plants.
earliest seedless vascular plants
forests with treesized plants up to 10 m had evolved. The Late Devonian
also witnessed the evolution of the flowerless seed plants
(gymnosperms), whose reproductive style freed them
from having to stay near water
end of the Devonian Period
a time of vast coal swamps,
where conditions were ideal for the seedless vascular
plants. With the onset of more arid conditions during
the Permian, the gymnosperms became the dominant
element of the world’s flora
Carboniferous Period
Which was the first plant group that did not require a
wet area for the reproductive part of its life cycle?
Gymnosperms
Which plant group first successfully invaded land?
Seedless vascular;
Which of the following is thought by many scientists to
be endothermic?
Therapsids;
Which reptile group gave rise to the mammals?
Therapsids;
Which evolutionary innovation allowed reptiles to
colonize all of the land?
An egg
that contained a food-and-waste sac and surrounded
the embryo in a fluid-filled sac;
In which period were amphibians and seedless vascular
plants most abundant?
Pennsylvanian
The discovery of Tiktaalik roseae is significant because it is
an
intermediate between lobe-finned fish and amphibians;
North America began separating from Africa. This was followed by the rifting of
North America from South America.
During the Late Triassic
, Antarctica
and Australia—which remained sutured together—
began separating from South America and Africa, and
India began rifting from Gondwana.
During the Late Triassic and Jurassic periods
South America and Africa began separating during
the and Europe and Africa began converging
during this time.
jurassic
The final stage in Pangaea’s breakup occurred during
the
e Cenozoic, when Greenland completely separated
from Europe and North America.
An increased rate of seafloor spreading during the d caused sea level to rise and transgressions to
occur
e Cretaceous Period
Except for incursions along the continental margin and
two major transgressions the North American craton was
above sea level during the Mesozoic Era.
s (the Sundance Sea and the Cretaceous Interior Seaway),
was the initial site of the separation of North America from Africa that began during
the Late Triassic During the Cretaceous Period, it was
inundated by marine transgressions.
Eastern Coastal Plain
the site of major evaporite
accumulation during the Jurassic as North America rifted
from South America. During the Cretaceous, it was inundated by a transgressing sea, which, at its maximum, connected with a sea transgressing from the north to create
the Cretaceous Interior Seaway
e Gulf Coastal region
e deposited in a variety of continental and marine
environments. One of the major controls of sediment
distribution patterns was tectonism.
+
Mesozoic rocks of the western region of North America
affected by four interrelated
orogenies: the Sonoma, Nevadan, Sevier, and Laramide.
Each involved igneous intrusions, as well as eastward
thrust faulting and folding.
Western North America
was the changing angle of subduction of the oceanic Farallon plate under the continental North American plate.
The timing, rate, and, to some degree, the direction of
plate movement were related to seafloor spreading and the
opening of the Atlantic Ocean.
cause of the Nevadan, Sevier, and Laramide orogenies
Orogenic activity associated with the oceanic–continental
convergent plate boundary in the Cordilleran mobile belt
explains the structural features of the western margin of
North America
. It is thought, however, that more than
25% of the North American western margin originated
from the accretion of terranes.
Mesozoic rocks contain a variety of mineral resources,
including
g coal, petroleum, uranium, gold, and copper
The formation or complex responsible for the spectacular
scenery of the Painted Desert and Petrified Forest is the
Chinle;
A possible cause for the eastward migration of igneous activity in the Cordilleran region during the Cretaceous was a change from
high-angle to low-angle subduction;
During the Jurassic, the newly forming Gulf of Mexico
was the site of primarily what type of deposition?
Evaporites;
Triassic rifting between which two continental landmasses initiated the breakup of Pangaea
Laurasia and Gondwana.
The first major seaway to flood North America was the
Cretaceous Interior Seaway;
The orogeny responsible for the present-day Rocky
Mountains is the
Laramide
The time of greatest post-Paleozoic inundation of the
craton occurred during which geologic period?
Cretaceous;
Which orogeny produced the Sierra Nevada, Southern
California, Idaho, and Coast Range batholiths?
Nevadan
Which formation or group filled the Late Triassic faultblock basins of the east coast of North America with red
nonmarine sediments?
Newark
Marine conditions returned to the region during the
Middle Jurassic when a seaway called the Sundance Sea twice
f ooded the interior of western North America
T e resulting deposits, the Sundance Formation, were produced from erosion of tectonic highlands to the west that
paralleled the shoreline. These highlands resulted from
intrusive igneous activity and associated volcanism that
began during the Triassic
A large part of the area
formerly occupied by the Sundance Sea was then covered
by multicolored sandstones, mudstones, shales, and occasional lenses of conglomerates that comprise the worldfamous Morrison Formation
Early Jurassic-age deposits in a large part of the western region consist mostly of clean, cross-bedded sandstones
indicative of wind-blown deposits. The lowermost unit is
the Wingate Sandstone, a desert dune deposit, which is overlain by the Kayenta Formation, a stream and lake deposit
(Figure 14.16a). These two formations are well exposed in
southwestern Utah. T e thickest and most prominent of the
Jurassic cross-bedded sandstones is the Navajo Sandstone
Unconformably overlying the
Moenkopi is the Upper Triassic Shinarump Conglomerate, a
widespread unit generally less than 50 m thick
Above the Shinarump are the multicolored shales,
siltstones, and sandstones of the Upper Triassic Chinle
Formation
. Like the Antler
orogeny, it resulted in the suturing of island-arc terranes
along the western edge of North America and the formation of a landmass called
Sonomia
Consequently, the two
Mesozoic cratonic sequences, the Absaroka Sequence (Late
Mississippian to Early Jurassic) and Zuni Sequence (Early
Jurassic to Early Paleocene) (see Figure 10.3), are not
treated separately here; instead, we will examine the
Mesozoic history of the three continental margin regions
of North America
Zuni Sequence
Cordilleran orogeny
Major Late Cretaceous transgression Reefs particularly abundant
Appalachian region
uplifted
South America and
Africa are widely
separated
Greenland begins
separating from
Europe
Regression at end of
Early Cretaceous
Early Cretaceous
transgression and
marine sedimentation
Cretaceous
Zuni
Erosion of fault-block
mountains formed
during the Late
Triassic to Early
Jurassic
jurassic and cretaceous
Sandstones, shales, and
limestones are deposited
in transgressing and
regressing seas
Thick evaporites are
deposited in newly
formed Gulf of Mexico
South America and
Africa begin
separating in the
Late Jurassic
Fault-block mountains
and basins develop in
eastern North America
Jurassic
Absaroka
jurassic and triassic
Subduction zone
develops as a result of
westward movement
of North America
Sonoma orogeny
Gulf of Mexico begins
forming during Late
Triassic
Deposition of Newark
Group; lava flows,
sills, and dikes
Breakup of Pangaea
begins with rifting
between Laurasia
and Gondwana
Supercontinent
Pangaea still in
existence
Triassic
Some of the most abundant invertebrates were
cephalopods, especially ammonoids, foraminifera, and the
reef-building rudists.
mesozoic
consisted of seedless vascular plants and gymnosperms.
Land plant communities of the Triassic and Jurassic
The angiosperms, or flowering plants, evolved during the
Early Cretaceous, diversified rapidly, and were soon the
most abundant land plants
Dinosaurs evolved from
small, bipedal archosaurs during
the Late Triassic, but they were most common during the
Jurassic and Cretaceous periods.
many paleontologists think some dinosaurs were indeed
endotherms.
paddle-like limbs could most
likely come out of the water to lay their eggs.
plesiosaurs
The marine
reptiles known as mosasaurs were most closely related to
lizards.
crocodiles became the dominant
freshwater predators. Turtles and lizards were present
during most of the
- During the Jurassic
Mesozoic
cretaceous lizards evolved to snake
w. Both marsupial
and placental mammals evolved during the
Cretaceous
from a group known as eupantotheres.
All dinosaurs with a bird-like pelvis belong to the order
Ornithischia
The middle ear bones of mammals evolved from which
of these bones in the mammal-like reptiles?
Articular and
quadrate;
Modification of the hand yielding an elongated finger for
wing support is found in
ptesaurus
Because of their rapid evolution and nektonic lifestyle,
the are good guide fossils.
cephalopods
Which of the following were common during the
Mesozoic, and are the major primary producers in the
warm seas today?
Dinoflagellates
The eupantotheres were the
probable ancestor of placental and marsupial
mammals;
Extinction of ammonites,
rudists, and most planktonic
foraminifera at end
of Cretaceous.
Continued diversification of
ammonites and belemnoids.
Rudists become major
reef builders
Extinctions of dinosaurs,
flying reptiles, marine
reptiles, and some marine
invertebrates.
Placental and marsupial
mammals diverge
Angiosperms evolve and
diversify rapidly.
Seedless plants and
gymnosperms still
common but less varied
and abundant.
Climate becomes more
seasonal and cooler at
end of Cretaceous.
North–south zonation of
climates more marked
but remains equable.
Cretaceous
Ammonites and belemnoid
cephalopods increase in
diversity.
Scleractinian coral reefs
common.
Appearance of rudist bivalves.
First birds (may have
evolved in Late Triassic).
Time of giant sauropod
dinosaurs.
Seedless vascular plants
and gymnosperms only
Much like Triassic.
Ferns with living relatives
restricted to tropics live at
high latitudes, indicating
mild climates.
Jurassic
The seas are repopulated by
invertebrates that survived
the Permian extinction event.
Bivalves and echinoids
expand into the infaunal
niche.
Cynodonts become extinct.
Mammals evolve from cynodonts.
Ancestral archosaur gives
rise to dinosaurs.
Flying reptiles and marine reptiles
evolve
Land flora of seedless
vascular plants and
gymnosperms as in
Late Paleozoic.
Warm temperate to tropical.
Mild temperatures extend
to high latitudes; polar
regions may have been
temperate.
Local areas of aridity.
Triassic
Cenozoic orogenic activity was concentrated in two
major belts
Alpine–Himalayan orogenic belt and the
circum-Pacific orogenic belt.
resulted from convergence of the
African and Eurasian plates. Mountain building took place
in southern Europe, the Middle East, and North Africa.
Plate motions also caused the closure of the Mediterranean
basin, which became a site of evaporite deposition.
* India separated from Gondwana, moved north, and
The Alpine orogeny
separated from Gondwana, moved north, and
eventually collided with Asia, causing deformation and
uplift of the Himalayas
India
characterized by subduction of oceanic
lithosphere and volcanism took place in the western and
northern Pacific Ocean basin. Back-arc spreading produced
back-arc marginal basins such as the Sea of Japan.
Orogens
Subduction of oceanic lithosphere occurred along the
western margins of the Americas during much of the Cenozoic
Subduction continues beneath Central and South America,
but the North American plate is now bounded mostly by
transform faults, except in the Pacific Northwest
info only
a complex mountainous region extending from Alaska into Mexico. Its
Cenozoic evolution included deformation during the
Laramide orogeny, extensional tectonics that formed
the Basin and Range structures, intrusive and extrusive
igneous activity, and uplift and erosion
The North American Cordillera
resulted in the vertical uplifts of the
Laramide orogeny. The Laramide orogen is centered
in the middle and southern Rockies, but deformation
occurred from Alaska to Mexico.
Shallow angle subduction of the Farallon plate beneath
North America
represent one of the world’s greatest eruptive
events. Volcanism continues in the Cascade Range of the
Pacific Northwest.
The Columbia River
basalts
Crustal extension in the Basin and Range Province
yielded north–south oriented, normal faults. Differential
movement on these faults produced uplifted ranges
separated
d by broad, sediment-filled basins
was deformed less than other areas
in the Cordillera. Late Neogene uplift and erosion were
responsible for the present topography of the region.
- The Colorado Plateau
resulted in its
collision with the Pacific–Farallon ridge. Subduction
ceased, and the continental margin became bounded by
major transform faults, except where the Juan de Fuca
plate continues to collide with North America.
The westward drift of North America
formed as north–south oriented
rifting took place in an area extending from Colorado into
Mexico. The basins within this rift filled with sediments
and volcanic rocks
The Rio Grande rift
were deposited
in intermontane basins, on the Great Plains, and in a
remnant of the Cretaceous epeiric sea in North Dakota.
Sediments eroded from Laramide uplifts
n took place throughout the Cenozoic, resulting
in seaward-thickening wedges of rocks grading from
terrestrial facies to marine facies.
Deposition on the Gulf Coastal Plain and Atlantic Coastal
Plain
n were responsible for the
present topography of the Appalachian Mountains.
Much of the sediment eroded from the Appalachians was
deposited on the Atlantic Coastal Plain
Cenozoic uplift and erosion
Paleogene and Neogene mineral resources include
oil
and natural gas, gold, and phosphorus-rich sedimentary
rocks.
A complex part of the circum-Pacific orogenic belt in the
United States is the
North
American Cordillera
As North America moved westward, the plate
was largely consumed as it was subducted beneath the
continent
Farallon.
Geologic evidence indicates that the Larmide orogeny
ceased during the
Eocene;
A vast area of overlapping lava flows mostly in Washington state is known as the
Columbia River basalts;
The Himalayas formed when the plate collided
with the plate.
Indian/Asian
Most of the Cenozoic-age sediment on the Atlantic
coastal plain was eroded from the:
Appalachian Mountains;
The most recent part of geologic time is the Pleistocene
) and the Holocene or Recent epochs
(1.8 million to 10,000 years ago)
(10,000 years ago to the present).
Although the Pleistocene is best known for widespread glaciers, it was also a time of
volcanism and
tectonism
Pleistocene glaciers covered about
30% of the land surface, and were most widespread on the Northern Hemisphere continents.
how many intervals of extensive Pleistocene glaciation
took place in North America, each separated by interglacial stages. Fossils and oxygen isotope data indicate about
20 warm–cold cycles occurred during the Pleistocene
4
Areas far beyond the ice were affected by Pleistocene glaciers
Climate belts were compressed toward the equator,
large pluvial lakes existed in what are now arid regions,
and when glaciers were present sea level was as much as
130 m lower than now
are found throughout Canada, in the northern
tier of states, and in many mountain ranges where valley
glaciers were present.
- Moraines, striations, outwash, and various other glacial
landforms
s caused
isostatic subsidence of Earth’s crust. When the glaciers
melted, isostatic rebound began and continues even now
in some areas.
The tremendous weight of Pleistocene glaciers
minor changes in
Earth’s rotation and orbit bring about climatic changes
that produce glacial-interglacial intervals
minor changes in
Earth’s rotation and orbit bring about climatic changes
that produce glacial-interglacial intervals
The causes of short-term climatic changes such as occurred during the Little Ice Age are unknown;
two proposed causes are variations in the amount of solar energy
and volcanism
Pleistocene mineral resources include
sand and gravel,
placer deposits of gold, and some evaporite minerals such
as borax
Lakes that existed during times of glaciation because of
increased rainfall and decreased evaporation are called
pluvial
The time from 1500 to sometime during the 1800s when
glaciers expanded markedly is referred to as the
Little Ice Age;
An important area of Pleistocene and Holocene volcanism in North America is
the Cascade Range;
The distinctive subdued topography resulting from erosion by continental glaciers with exposed, striated bedrock and little soil is a(n)
ice-scoured plain
The most recent episode of glaciation in North America
is the
Wisconsinan
A large pluvial lake that was the forerunner of the Great
Salt Lake was
Lake Bonneville
North America was
covered by subtropical and tropical forests, but the climate
became drier by Oligocene and Miocene time, especially
in the midcontinent region.
During much of the Early Cenozoic
better known for mammals than
for other classes of vertebrates, because mammals have
a good fossil record, their teeth are so distinctive, and
Cenozoic deposits are easily accessible.
- Evolutionary history
descended from
shrewlike ancestors that existed from Late Cretaceous to
Paleogene time.
placental and marsupial mammals
The most common ungulates are the
even-toed hoofed
mammals (artiodactyls) and odd-toed hoofed mammals (perissodactyls), both of which evolved during the Eocene. Many ungulates show evolutionary trends such
as molarization of the premolars as well as lengthening of
the legs for speed.
perissodactyls were more common
than artiodactyls but now their 16 living species constitute
less than 10% of the world’s hoofed mammal fauna
During the Paleogene
Although present-day Equus differs considerably from the
oldest known member of the horse family
, Hyracotherium,
an excellent fossil record shows a continuous series of animals linking the two
Even though horses, rhinoceroses, and tapirs, as well as
the extinct titanotheres and chalicotheres, do not closely
resemble one another, fossils show they diverged from a
common ancestor during the
Eocene
evolved from rather small ancestors, became
quite diverse and abundant, especially on the Northern
Hemisphere continents, and then dwindled to only three
living species
Elephants
South America was isolated,
and its mammal fauna was unique. A land connection was
established between the Americas during the Late Cenozoic,
and migrations in both directions took place
During most of the Cenozoic
One important evolutionary trend in Pleistocene mammals and some birds was toward giantism. Many of these
large species died out, beginning about
40,000 years ago.
Horses, rhinoceroses, and tapirs are all members of the
mammal order Perissodactyla which is also known as the
mammals.
odd-toed
During the Cenozoic Era, Earth’s temperature was highest during the
paleocene-eocene
Cenozoic bryozoans were particularly abundant and
successful
suspension
feeders;
One indication of a cool climate is
small leaves with incised margins
One feature of Eocene whales that indicates they had
land-dwelling ancestors is
vestigial rear
limbs;
One of the major components of the Cenozoic marine
invertebrate fauna was
foraminifera
The primates evolved during the
e Paleocene. Several trends
help characterize primates and differentiate them from
other mammalian orders, including a change in overall
skeletal structure and mode of locomotion, an increase in
brain size, stereoscopic vision, and evolution of a grasping
hand with opposable thumb
oldest primate
lineage and include lemurs, lorises, tarsiers, and tree
shrews
prosimians
New and Old World
monkeys, apes, and hominids, which are humans and
their extinct ancestors
e anthropoids
The oldest known hominid is
Sahelanthropus tchadensis, dated at nearly 7 million years. It was followed by
Orrorin tugenensis at 6 million years, then two subspecies of Ardipithecus at 5.8 and 4.4 million years, respectively. These early hominids were succeeded by the
australopithecines, a fully bipedal group that evolved in
Africa 4.2 million years ago. Recent discoveries indicate
Ardipithecus evolved into Australopithecus. Currently,
five australopithecine species are known: Australopithecus anamensis, A. afarensis, A. africanus, A. robustus,
and A. boisei.
The human lineage began approximately 2.5 million
years ago in Africa with the evolution of
Homo habilis,
which survived as a species until about 1.6 million
years ago.
evolved from H. habilis approximately
1.8 million years ago and was the first hominid to migrate out of Africa, spreading to Europe, India, China,
and Indonesia, between 1.8 and 1 million years ago. The
transition from H. erectus to H. sapiens is still unresolved
because there is presently insufficient evidence to determine which hypothesis—the “out of Africa” or the “multiregional” hypothesis—is correct. Nonetheless, H. erectus
used fire, made tools, and lived in caves.
Homo erectus
inhabited Europe and the Near East between 200,000 and 30,000 years ago and were not much
different from present-day humans. They were, however,
more robust and had differently shaped skulls. In addition, they made specialized tools and weapons, apparently
took care of their injured, and buried their dead
Neanderthals
were the successors of the Neanderthals and lived from about 35,000 to 10,000 years ago.
They were highly skilled nomadic hunters, formed living groups of various sizes, and were also skilled cave
painters.
The Cro-Magnons
Modern humans succeeded the Cro-Magnons about
10,000 years ago and have spread throughout the world,
as well as having set foot on the Moon.
The oldest currently known hominid is
Sahelanthropus tchadensis
Which extinct lineage of humans were skilled hunters
and cave painters?
cro magnon
The first hominids to migrate out of Africa and from
which we evolved were
Homo erectus;
To which of the following species do Java Man and
Peking Man belong?
Homo erectus;
Which is the oldest primate lineage?
Prosimians
The oldest known australopithecine is Australopithecus
afarensis
Which of the following is a hominid?
modern humans, chimpanzees, gorillas and orang-utans
According to archaeological evidence, which were the
first hominids to use fire?
homo erectus
