Geological Eras-Camila Carrillo

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• Covers almost 4,000 milions years. Is the formation of the lithosphere, the ocean and the almosphere.

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• Spans 560 million years, has three eras and reaches the present time, the Holocene.

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• Era spanned 312 millions years and is when the Earth was divided into several continents.

1. Cambrian

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   • It lasted for about 13 – 25 million years and animal fossils began to appear.
   1. Ordovician

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      • Lasted almost 45 million years and in this period, the area north of the tropics was almost entirely ocean, and most of the world's land was collected into the southern supercontinent Gondwana.
      1. Silurian

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         • The sea was leveling out which generated rivers, ecosystems, etc.
         1. Devonian

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            • It was a time when extensive reefs were built in the shallow waters that surrounded each continent and separated Gondwana from Euramerica.
            1. Mississippian

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               • Shallow, low-latitude seas and lush terrestrial swamps covered the interior of the North American continent.
               1. Pennsylvanian

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                  • The spreading swamps established the thick beds of dead plant material that today make up most of the world's coal.
                  1. Permian

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                     • Pangaea presented severe extremes of climate and environment due to its vast size and which ended in the largest mass extinction the Earth has ever known.

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• The era for the dinosaurs, plant life and the continents are getting closer to their current appearance.

1. Cretaseous

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   • 65 million years ago, an asteroid collided with Earth in Mexico's Yucatán Peninsula, forming what is now called the Chicxulub impact crater.
   1. Jurassic

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      • The supercontinent Pangea broke up and dinosaurs kept appearing.
      1. Triassic

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         • It was a desolate time in Earth's history, violent volcanic eruptions, climate change, a fatal encounter with a comet or asteroid that had caused the extinction of more than 90% of Earth's species.

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• Era formed the Andes (movement of the Nazca plate, below the South American plate).

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• Spands the last 65 millions years, up to the present day. Collision of Asia with India and Arabia with Euracia. Dinosaurians disappear and current human begin appears.

1. Paleocene

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   • It began with the mass extinction event at the end of the Cretaceous, the disappearance of dinosaurs, not birds, giant marine reptiles, and much fauna and flora.
   1. Eocene

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      • The warmest period during the Cenozoic, marked the decline into an icy climate and the rapid expansion of the Antarctic ice sheet.
      1. Oligocene

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         • It is the third and last epoch of the Paleogene. Global expansion of grasslands and a regression of tropical broadleaf forests to the equatorial belt.
         1. Miocene

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            • Time of warmer global climates and appearance of: kelp forests and grasslands.
            1. Pliocene

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               • The tectonic plates of India and Asia collided, forming the Himalayas. In North America, waterfalls rose, the Rocky Mountains rose, and there was activity in the mountains of Alaska and the Great Basin mountain ranges of Nevada and Utah.
               1. Pleistocene

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                  • It began about 2.6 million years ago. The Ice Age where glaciers formed that covered large parts of planet Earth.
                  1. Holocene

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                     • It began 12,000 to 11,500 years ago. When the Earth entered a warming trend, the glaciers retreated. The tundra gave way to the forest.