Transcript Earth History - Lucinda Supernavage

Earth History
Sections
• 1. Precambrian Earth
• 2. Paleozoic Era
• 3. Mesozoic Era
• 4. Cenozoic Era
Precambrian Earth
Geologic Time Scale
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The geologic time scale is a record of
Earth’s History
The Earth is 4.6 Billion Years Old
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Precambrian (4.6 bya – 543 mya)
Paleozoic Era (543 mya – 250 mya)
Mesozoic Era (250 mya – 65 mya)
Cenozoic Era (65 mya – Present)
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Origin Of Earth
4.6 Bya – Earth Formed
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Solar Neblua Hypothesis – Cloud of dust and gas collapsed by the force of gravity
Formed the sun and the other planets in the solar system
4.0 Bya – Earth had a stable crust, oceans and atmosphere
Origin Of Life
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3.8 Bya-First life forms evolved
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Stromatolites – Mounds of cyanobacteria
Were photosynthetic – Consumed carbon dioxide, produced oxygen
Created Earth’s oxygen supply
First Continents
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3.5 Bya-The first continents began to form
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Convection began due to unequal heating of the mantle (plate tectonics)
Caused the landmasses to move apart
Atmosphere
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2.5 Bya – Atmosphere became dominated by oxygen
1.8 Bya – First cells with nuclei appeared
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Eukaryotes – WILL Need to know for Biology!
NC Mountains
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1.7 Bya- Present day North Carolina formed
1.3 Bya-The first mountains of North Carolina formed
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Grenville mountains (no longer exist due to erosion)
Formed by Grenville Orogeny
Oldest rocks of NC formed. Presently exposed in the Appalachian Mountains
First Multi-Celled Organisms
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1 Bya – First multi-celled organisms
600 mya – First sponges and worm like animals appeared
NC Flooding
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620 mya-North Carolina was pulled apart by tectonic forces
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Seas covered North Carolina
Volcanic island arcs developed along NC-VA border
Paleozoic Era
Cambrian Explosion
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542 mya-”Cambrian Explosion” – Major diversification of life
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First vertebrates
North Carolina was still underwater
Rodinia
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540 mya-North America and Europe/ Africa moved towards each
other
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Formed Kings Mountain Belt
Formed supercontinent Rodinia
Taconic Orogeny
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496-440 mya-Taconic Orogeny: The coastline of present day
Appalachian Mountains collided with Iapetus Plate (Oceanic Plate)
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Formed volcanic mountains in present day North Carolina
Paleozoic Fish
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444 mya – Fish were dominant
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First jawed fish
Sea scorpions
Trilobites
Mollusks
First land plants
Acadian Orogeny
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Acadian Orogeny (400-325 mya): A continent
called Avalonia collided with present day North
America
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Continued the formation of the Appalachian
mountains.
Also lead to the formation of Pangaea
Coal Forests
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359 mya-Wetland forests dominated the Appalachian area
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The decayed organic matter from the trees lead to coal that is currently mined
today
Alleghanian Orogeny
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Alleghanian Orogeny (325-260 mya): Africa collided with North
America.
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Pangaea was fully assembled.
Appalachians were fully formed, in the center of Pangaea
Permian Mass Extinction
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251 mya – Permian Mass Extinction
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Drop in sea level, resulted in 95% of all life going extinct
Possible changes in climate
75% of amphibians, 80% of reptiles disappeared
Mesozoic Era
Appalachian Erosion
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251 mya-Appalachians began to erode
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Wind and rain → Sediment was carried to lower lying land or sea
Pangaea was breaking up
North Carolina was near the equator, had a tropical climate
Mesozoic Events
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250 mya – Dinosaurs first appeared → Were dominant organisms
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First mammals appeared
First crocodiles
Ichthyosaurs-Dolphin like organisms in the seas
Pangaea Separation
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200 mya-As Pangaea separated the Atlantic Ocean formed
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Outer margin became the outer banks
Atlantic Ocean began to open up
Mesozoic Life
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200 mya- Dinosaurs were still dominant
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Mammals began to grow in numbers → Still not dominant
First birds and lizards
Coastal Plain Flooding
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145 mya-65 mya: Coastal Plains were underwater but sea level began to drop
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Pangaea continued to split up
Southern landmasses broke up → Africa and South America created
Mesozoic Extinction
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65 mya – Mass extinction: All dinosaurs went extinct
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Most geologists think a meteorite hit in the Yucatan Peninsula in Mexico which
caused this → Supported by presence of iridium
Title
Cenozoic Era
Cenozoic Life
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65 mya - Mammals began to dominate. First large mammals appeared
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World’s climate was tropical however was starting to cool
57 mya – Coastal Plains were now above sea level
First Mammals
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55 mya – First modern mammals evolved
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Whales diversified
Coastal Plains flooded again → Seas stretched up to the Western Piedmont
Modern Mammals
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23 mya – Modern mammals and birds appeared
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Grasses dominated the Earth
Ocean retreated from the coastal plains
Blue Ridge Mountains
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5 mya-Blue Ridge and Piedmont were as they are today
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First human ancestors
Coastal Plains were flooded again but waters receded
Sand Hills Developed – Streams eroded piedmont and sent sediment to the coastal plains
Fall Line – Sharp drop off in elevation. Located around Fayetteville
Ice Age
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1.7 mya-”Ice Age” began.
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There is present day evidence in the Coastal Plains
Glacial Till
18,000 years ago – Glaciers melted
Human Civilization
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10,000-15,000-North Carolina’s forests began to develop
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Look as they do now
9,000 BC-Human civilization began
Assignment
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Make a timeline showing the history of the earth with
each Period and Era Listed
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After making the timeline, begin looking over notes and
preparing to study for our Exam Wednesday