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24 Cards in this Set
- Front
- Back
Permian/Triassic Boundary |
The time break when up to 90% of all species (especially those in the marine realm) went extinct at around 251 Ma. This constitutes the most significant mass extinction in Earth history. |
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Cretaceous/Tertiary Boundary |
The time break at which the dinosaurs and many other organisms went extinct, perhaps as the result of a bolide impact (to make the Chicxulub Crater). This is the infamous "KT boundary"! |
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PreC/Cambrian Boundary |
The time break at which many complex, multi-cellular animals with shells and skeletons first appeared in the fossil record. |
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Hadean |
The first time slice (Eon) of the Precambrian. We know very little about this very old time slice because very few rocks exist from it (no Earth rocks--just a few meteorites and zircon mineral grains)! It begins with the origin of the Earth and Moon, differentiation of the core and mantle, and formation of the earliest atmosphere. |
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Phanerozoic |
The Eon when life became extremely diverse and abundant, with millions of different forms living in the sea and then on land. The word literally means "visible life". |
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Archean |
An Eon of the Precambrian. During this lengthy time, life got started (with single-celled fossils and stromatolites), continental crust formed and cratons developed. |
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Proterozoic |
Another Eon during Precambrian time. During this time, and oxygenated atmosphere formed (recorded by BIF's), ancient super-continents (such as Rodinia) assembled and broke up, continental glaciations ebbed and flowed, and sex (!!) came about. |
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Precambrian (PreC) |
The time slice that makes up the vast majority of geologic time (88+%). Life, the atmosphere, oceans, tectonics, and continents originated during this time.
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Cenozoic |
Mammals become the dominant life form during this "new life" Era. We are currently living in this Era, as well. Ice caps come and go and the Alpine-Himalayan Chain formed and continues to do so.
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Mesozoic |
The Era the occurred between 251 and 65 Ma. Its root words mean "middle life". Reptiles, especially dinosaurs, ruled during this time. Pangea was intact at the beginning but broke apart during this time. |
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Paleozoic |
Shelled organisms (invertebrates) and the first land plants all appeared during this "old life" Era. The age of fishes and amphibians occurred during this time.
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Ordovician |
The Period when fish show up in the fossil record. They began to radiate at this time. A major extinction event occurred near the end of this period. Also, the Taconic Orogeny occurs, signaling the beginning of Appalachian Mountain formation.
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Cambrian |
The Period that began about 542 Ma. An "explosion" of life occurred during this first Period of the Paleozoic (all major phyla of animals, except one, make their appearance during this time).
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Carboniferous |
A period of extensive plant-life preservation in coastal swamps, especially in Pennsylvania (but also in Europe). Many carbon-rich coal beds were deposited during this time. Reptiles also make their appearance in the fossil record.
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Silurian |
The Period that marks the appearance of vascular plants. Large reefs grew in shallow seas. Also, fishes were proliferating during this time.
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Devonian |
The Period that marks the appearance of animals (insects and amphibians) onto land. A major extinction occurred near the end of this Period (environment got bad...). Also, the Acadian Orogeny occurred, marking the second major phase of Appalachian Mountain building.
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Permian |
The Period when Pangea was fully assembled into a supercontinent to make the Appalachian Mountains. This orogeny is called the Alleghanian. Also, a super-mega-major mass extinction occurred at the end of this Period.
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Triassic |
Dinosaurs (and other reptiles), as well as mammals, became important life forms in this Period.
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Jurassic |
A movie was made, making this the most well known Period of all!! Stegosaurus was around at this time, but Tyrannosaurus Rex was not. Also, Pangea was breaking up at this time, and the Atlantic Ocean began to open.
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Cretaceous |
The last Period that dinosaurs (such as T-Rex) were alive and kicking. The Rocky Mountains began forming during this time, as the result of the Sevier and Laramide orogenies. Flowering plants also emerged. |
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Quaternary |
The Period we are currently living in. This Period began about 2.6 million years ago. Its root means "fourth", and the named of this time slice is a relict from the 19th century when the time scale was first devised.
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Tertiary |
The first Period after the extinction of the dinosaurs. The Alps and Himalayas started to rise as the Tethys Sea closed and continents collided. The Laramide Orogeny ended in the west, with plate motions changing to cause extension and shearing that formed the Basin and the Range and San Andreas. Also, primates, horses, whales and other mammals diversified and climates fluctuated. This Period is now split into the Paleogene and Neogene periods.
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Pleistocene |
The Epoch of widespread glaciation known as the "Ice Ages". Many landforms from this event can be found throughout North America, including the moraines of northwestern Pennsylvania. Climates changed wildly, sea level rose and fell, and organisms tried to keep up with the changes.
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Holocene |
The Epoch we (being Homo sapiens) are currently living in. By the way, insects rule! Some consider this a time of human-induced mass extinction, thus the proposal to break out a time slice called the Anthropocene. Will the end of this time slice be defined by our own extinction? Who will define it? |