Proterozoic Eon Flashcards
How long did the Proterozoic Eon last
1.958 BY
The Proterozoic Eon accounted for _% of all geologic time
42.5%
What caused Kenorland’s rifting
magma plume rifting
The _ and _cratons began to drift apart by 2.45 Ga
Kola, Karelia
By _ Ga, Kola Craton was located at ~_ degrees and Karelia at ~_ degrees
2.4 Ga, 15 Degrees, 30 Degrees
The breakup of Kenorland was contemporary with what?
Huronian Glaciation
The Huronian Glaciation lasted from _ B.Y to _ B.Y
2.4 B.Y to 2.1 BY
What caused the Huronian Glaciation
The Great Oxygenation Event
What were the effects of the Great Oxygenation Event
- Deposition of Banded Iron Formation
- Huronian Glaciation
How did the Great Oxygenation Event cause an Ice Age?
Methane was the dominant greenhouse gas. However, the abundant oxygen reacted with it to create CO2, a much less effective greenhouse gas, causing an ice age.
Kenorland provided the _ around which the Proterozoic crust accreted
nuclei
What made up Laurentia
North America, Greenland, parts of Northwestern Scotland, parts of Baltic Shield of Scandinavia
Continent forming includes:
- Amalgamation of Cratons
- Accretion of Volcanic Arcs and Oceanic Terranes
- Extensive Plutonism, Metamorphism, and Volcanism
Oldest and Longest Ice Age (300 Million Years)
Huronian Glaciation
The Huronian Glaciation is also called as?
Snowball Earth Episode 1
What kind of organisms existed during the Huronian Glaciation?
Unicellular Organisms
True or False
The Great oxygenation event caused the first mass extinction on Earth.
True
The most famous rock of the Proterozoic Eon.
Banded Iron Formation
Are distinctive units of sedimentary rock that are
consists of repeated, thin layers (a few millimeters to a few centimeters in thickness) of silver to black iron oxides, either magnetite (Fe3O4) or hematite (Fe2O3), alternating with bands of iron-poor shales and cherts, often red in color, of similar thickness, and containing microbands (sub-millimeter) of iron oxides.
Banded Iron Formations
When the Cyanobacteria flourished, minerals and other sinks became saturated. It built up in the water, in the air . To the other bacteria living in the ocean—anaerobic bacteria, remember—oxygen was toxic. The cyanobacteria were literally respiring poison. Why did this event happen.
They could no longer absorb the oxygen being produced.
What triggered the Huronian Glaciation?
Drop in levels of greenhouse gases such as Methane (CH₄) and Carbon Dioxide (CO₂), which keeps the planet warm.
A landmass made up of what are now
North America, Greenland, parts of
northwestern Scotland, and perhaps some of
the Baltic shield of Scandinavia.
Laurentia
Delete card
True or False
The Paleoproterozoic History of Laurentia is not related to the Wilson Cycle.
False, it is also related.
Is named after the Canadian geologist J. Tuzo Wilson, includes rifting and the opening of an ocean basin with passive continental margins on both sides. As a result of rifting, an expansive ocean basin forms, but eventually it begins to close, and subduction zones and volcanic island arcs form on both sides of the ocean basin. Finally, a continent-continent collision takes place resulting in deformation of the passive margin deposits as well as rocks of the oceanic crust.
The Wilson Cycle
How many stages does the Wilson Cycle have?
Seven
Columbia existed from ____ to ____ billons years ago, that is, from the beginning of the Statherian period until the end of the Calymmian.
1.8 to 1.5 BYA
What is the other names for the supercontinent Columbia?
Nuna or Hudsonland
Assumed dimensions of Columbia in North to south and East to West
N-S: 12,900 km
E-W: 4,800 km
The supercontinent Columbia slowly began to break up into parts from ____ to ____ years ago.
1.6 to 1.2 BYA
Columbia consisted of ___________ that
made up the cores of the continents
of Laurentia, Baltica, Ukrainian
Shield, Amazonian Shield, Australia, and
possibly Siberia, North China, and Kalahari as
well.
Proto-Cratons
True or False
Columbia is smaller than Kenorland.
False, it is much bigger.
List all of the countries that were tightly clumped together when the supercontinent columbia still existed.
North America, Scandinavia, Australia, India, South America, Brazil, Canada
Also known as the North American Craton is a large continental craton that forms the ancient geological core of the North American continent.
Laurentia
_________ was a late-Proterozoic, early-Palaeozoic continent that now includes the East
European craton of northwestern Eurasia.
Baltica
The _______ _______ is a geologic province located in South America. It occupies a large portion of the central, north and eastern part of the continent
Amazonian Craton
The ______ ______ is a craton, an old and stable part of the continental lithosphere that occupies a large portion of South Africa and consists of the Kaapvaal, the Zimbabwe Craton, the Limpopo Belt, and the Namaqua Belt
Kalahari Craton
A Mesoproterozoic orogenic event in
Laurentia, the 1.3- to 1.0-billion-year-old, the
_________ _________, took place in the eastern
part of the evolving continent . Grenville rocks
are well exposed in the present-day northern
Appalachian Mountains as well as in eastern
Canada, Greenland, and Scandinavia
Grenville Orogeny
Why is the Grenville Orogeny significant?
It may have been the final episode in the assembly of the supercontinent Rodinia which persisted into the Neoproterozoic.
A supercontinent, consists of at least ______ continents merged into one, and in the context
of Earth history, we usually refer to a supercontinent as one composed of all or most of Earth’s landmasses, other than oceanic islands.
Two
Supercontinents may have existed as early as
the __________ Era.
Neoarchean
The first supercontinent that is recognized with certainty is known as?
Rodinia
The supercontinent Rodinia assembled between ____ and _____ billion years ago and then began fragmenting ______ million years ago.
1.3 and 1.0 BYA, 750 MYA
Geologists refer to the superocean that surrounds Rodinia as?
Mirovia
True or False
Rodinia remained almost entirely in the
Northern Hemisphere and is a very important
part of earth’s biological history.
False, it remained almost entirely in the Southern hemisphere.
What significant scientific events occured in the supercontinent Rodinia or when the supercontinent Rodinia is still present.
- Evolution of Eukaryotes into Multicellular Organisms
- First Appearance of Sexual Reproduction
- Formation of the Ozone Layer in the Atmosphere
The breakup of the supercontinent Rodinia led to what?
Cryogenian Ice Age
Cryogenian Ice age is also known as?
Varangian Glaciation
True or False
During the Crogenian Ice Age, Ice caps and glaciers extended all the way from the poles to the middle of equator, covering every inch of the planet, making it look like a giant snowball.
True
During the Crogenian Ice Age, the most intense to have ever occured, the earth looked like a giant snowball, this phenomenon is called as?
Snowball Earth
True or False
The Cryogenian ice age was caused due to three rapid glaciation events in the ice age.
False, there were only two, where in between a warm interglacial period also occured.
The Cryogenian Ice Age, the most
extreme ice age on our planet lasted from _____
mya to _____ mya.
720 to 635 MYA
What are the evidences of the Cryogenian Ice Age?
Tillites and Other Glacial Features Aged 900 and 600 MYO were found in every continent except Antacrtica.
_______ sedimentary rock that consists of consolidated masses of unweathered blocks (large, angular, detached rock bodies) and glacial till (unsorted and unstratified rock material deposited by glacial ice) in a rock flour (matrix or paste of unweathered rock). The matrix, which comprises a large percentage of the rock, usually is dark gray to greenish black in colour and consists of angular quartz and feldspar grains and rock fragments in a very fine-grained paste.
Tillites
Two organisms that became common during the Proterozoic Eon.
Stromatolites and Cyanobacteria
Organisms that sexually reproduces evolved during the _______ Era.
Mesoproterozoic Era
True or False
There were organisms that inhabited the supercontinent Rodinia.
False, since it predated the formation of the Ozone Layer, it was too exposed to Ultraviolet Sunlight, making terrestrial life impossible.
True or False
Marine life also didn’t flourish similarly to terrestrial life during the time when Rodinia was present.
False, marine life did in fact flourished.
What caused the rise in numbers of shallower seas?
Uplift of ocean floors, causing sea levels to rise.
True or False
Mesoproterozoic rocks 1.2 billion years old in
Canada contain fossils of the oldest known
eukaryotes.
True
________ were single celled, probably reproduced sexually, and look remarkably similar to living red algae that existed during the Mesoproterozoic Era.
Bangiomorphia
Is the oldest known megafossil, but it was very likely a singlecelled bacterium or some kind of algae found in the 2.1 BYO Negaunee Iron Formation.
Grypania
Hollow fossils known as _________ that were probably cysts of planktonic algae become common during the Meso- and Neoproterozoic Eras.
Acritarchs
True or False
According to a widely accepted theory,
eukaryotic cells formed from prokaryotic cells
that entered into a symbiotic relationship.
True
During the Proterozoic Eon, there are cases where one symbiont lived within the other, which is a special type of symbiosis called ___________.
Endosymbiosis
The first fairly controversy-free fossils of
animals come from the _________ _________
of Australia and similar faunas of about the
same age elsewhere.
Ediacaran Fauna
Other term for the Edicaran Fauna.
Avalon Explosion
True or False
In 1947, an Australian geologist, R. C. Sprigg,
discovered impressions of hard-bodied animals
in the Pound Quartzite in the Ediacara Hills of
South Australia.
False, it was the impressions of soft-bodied animals.
The collective name for fossil associations similar to those in the Ediacara Hills, is now known from all continents except Antarctica.
The Ediacaran Fauna
True or False
Some investigators think that three present-day phyla are represented in the Ediacaran fauna: jellyfish and sea pens (phylum Cnidaria), segmented worms (phylum Annelida), and primitive members of the phylum Arthropoda (the phylum with insects, spiders, crabs, and others).
True
One Ediacaran fossil, __________, has been cited as a possible ancestor of trilobites, and another may be a primitive member of the phylum Echinodermata.
Spriggina
large-scale deformation called
the ____-_________ _________ that took place in
what are now the Southern Hemisphere
continents, Rodinia’s separate pieces
reassembled about 650 million years ago and
formed another supercontinent.
Pan-African Orogeny.
When the separate pieces of Rodinia reassembled 650 MYA, it formed another supercontinent named ________.
Panotia/Pannotia
________, meaning “all southern land”, also known as Vendian supercontinent, Greater Gondwana, and the Pan-African supercontinent, was a relatively short-lived Neoproterozoic supercontinent that formed at the end of the Precambrian during the Pan-African orogeny.
Pannotia
When did Panotia formed and broke apart?
Formed: 650 to 500 MYA
Broke Apart: 550 MYA
The name of the Ocean that was present when Panotia existed.
Iapetus Ocean
