Geology

Formation of Planet Earth

Our Milky Way galaxy came together nearly 14 billion years ago when enormous clouds of gas and dust coalesced under the force of gravity. Over time, two structures emerged: first, a vast spherical “halo,” and later, a dense, bright disk. Billions of years after that, our own solar system spun into being inside this disk, so that when we look out at night, we see the Milky Way.

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Layers of Planet Earth

The Earth is made of many layers. We live on the outer layer, a thin layer of rock and water floating on an ocean of molten rocks and metals.

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Change and Plate Tectonics

Main Ideas The Earth’s crust is made of tectonic plates that are floating on the hot magma below. The tectonic plates are moving, and rub against each other. This movement causes earthquakes, volcanoes, mountain ranges, tsunamis, and even geysers. Scientists think that long ago there was one huge continent. We call it Pangaea. In time, Pangaea broke apart creating the continents we have now. The Ring of Fire is a ring of active volcanoes that surrounds the Pacific Plate.

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Fire and the Earth

Volcanoes have existed for a long time on Earth, and they deserve our greatest respect. They may have caused major planetary disasters, such as the Permian Mass Extinction about 250 million years ago, which may have been the greatest mass extinction on Earth.

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Pele: Goddess of Fire

Pele, the Hawaiian Goddess of Fire—like the volcanos she represents—deserves our greatest respect. Hew beauty is awe-inspiring, her moods fiery, and her fury immense.

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Types of Rocks

Main Ideas Rocks travel through a Rock Cycle, usually from igneous, to sedimentary, to metamorphic, and finally back to igneous. There are three kinds of rocks, igneous, sedimentary, and metamorphic. Igneous rocks form out of magma that is pushed up to the surface of the Earth. Three examples of igneous rock are… Sedimentary rocks accumulate in layers when particles settle out of water or air. Sedimentary rocks often contain fossils.

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Experiment: Growing Salt Crystals

Create a supersaturated solution. As the solution becomes unstable, salt crystals will form.

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Crystals

Crystals are the outer form of a mineral’s inner order. Nearly every piece of rock on Earth is made of minerals, each of which has a precise arrangement of atoms.

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Fossils

Main Ideas Fossils are part of the cycle of life. All living being are made of matter, and when they die the matter in their bodies returns to the material world. A fossil is any evidence of prehistoric life (plant or animal) that is at least 10,000 years old. The most commonly found fossils are bones and teeth, but fossils of footprints and skin impressions exist as well. Fossils are excavated from many environments, including ancient riverbeds, lakes, caves, volcanic ash falls, and tar pits.

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Deep Ocean Vents

Main Ideas Ocean vents erupt out of deep cracks in the ocean floor. Ocean vents are hydrothermal (hot water). Other types of hydrothermal vents include hot springs and geysers. Ocean vents eject hot, toxic, fluids and gases into the seawater. They are often located near regions of tectonic activity. Ocean vents create some of the most hostile habitats on Earth, but even here life has evolved to survive. Ocean vents are a type of hydrothermal vent.

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Mt Lassen Field Trip, Woodland Star School, Sonoma, California

Awesome trip to the high country. Wild storms, lightening on the water, flooded tents, tough hikes, hungry bears, dark caves, hot lava, great food, and more…

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1 Quotation on Geology

“Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives... a mote of dust suspended in a sunbeam... To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.”

Carl Sagan