histo Flashcards by Unknown Unknown

in North America, made up of smaller units delineated by their ages and structural trends

Canadian shield

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belts are linear, syncline-like bodies
of rock found within much more extensive granite-gneiss
complexes

Archean greenstone

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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

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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

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formed by the activities of photosynthesizing bacteria are found in rocks as much as 3.5 billion
years old

Stromatolites

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Archean mineral resources

gold, chrome, zinc,
copper, and nickel.

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the most widespread Archean-age rocks

Granite-gneiss complexes

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greenstone belts is not fully resolved, but
many geologists think that some of them formed in

backarc marginal basins

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Age of most greenstone
belts, North America

Neoarchean

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Oldest well-documented
stromatolites

Mesoarchean

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Origin of continental crust, Possible stromatolites

Paleoarchean

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Well-preserved greenstone
belts, South Africa

boundary of eoarchean and paleoarchean

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Isua greenstone belt, Greenland
Chemical evidence
for life

Eoarchean

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Acasta Gneiss, Canada

Eoarchean 4000 mya

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-earth bombarded by meteorites and comets
-Oldest meteorites and
moon rocks
-Detrital zircons, Australia
-Origin of Earth’s moon

Eoarchean

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consisting mostly of North America and
Greenland

Laurentia

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Paleoproterozoic collisions between Archean cratons
formed larger cratons that served as nuclei, around
which crust accreted. One large landmass so formed
was

Laurentia

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important events in the
evolution of Laurentia.

Paleoproterozoic amalgamation of cratons, followed by
Mesoproterozoic igneous activity, the Grenville orogeny,
and the Midcontinent rift

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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

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common by Proterozoic time

Sandstone-carbonate-shale assemblages deposited on passive continental margins w

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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

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Photosynthesis continued to release free oxygen into the
atmosphere, which became increasingly rich in oxygen
through the

e Proterozoic.

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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.

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proof Earth’s atmosphere had enough
free oxygen for oxidation of iron compounds

Widespread continental red beds dating from 1.8 billion
years ag

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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

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

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