Earth Systems Flashcards
Define Geology
Earth’s structure, composition and processes set into a historical context.
- Can predict outcomes
- Interpret past tectonics, climate change, ocean, geography, processes from looking at the layers of sediment in the rocks.
Define Physcial Geography
Are the underlying processes (e.g tectonic) then looking at the human aspect between the components of the earth system especially Spatio-temporal scales.
- The natural environment
- How it came about
- How we adapt and manipulate
- Resources and threats
What are the four spheres?
- Atmosphere
- Hydrosphere (oceans)
- Biosphere (life - vegetation)
- Geosphere (solid earth)
Describe the Atmosphere
Earth is surrounded by this gases sphere.
It provides us with oxygen and carbon dioxide for life and protects us from the sun’s ultraviolet radiation.
The space between the atmosphere and Earth’s surface is called weather and climate.
Describe the Hydrosphere
The hydrosphere is a dynamic mass of water that is continually on the move, evaporating, precipitating to the land, and running back into the ocean again.
Covers 71% of Earth.
Average depth of 3,800m.
Accounts for 97% of Earth’s water.
What is included in the hydrosphere?
Oceans, lakes, streams, glaciers, and underground water.
Describe the Biosphere
The biosphere includes all life on Earth. Contains extreme environments.
Ocean life is concentrated in the sunlit surface waters of the sea. Most life is concentrated near the surface, with tree roots and burrowing animals reaching a few meters below ground, while flying insects and birds reaching a few km into the atmosphere.
What are the extreme environments in the Biosphere?
- On the ocean floor, where pressures are extreme and no light penetrates, there are places where vents spew hot, mineral-rich fluids that support communities of exotic form.
- On land, some bacteria thrive in rocks as deep as 4km and in boiling hot springs.
- Air currents can carry micro-organisms many km into the atmosphere.
However, overall life is considered to be situated along a thin band near the Earth’s surface.
Describe the Geosphere
The Geosphere extends from the surface to the centre of the planet (depth of 6,400km - largest sphere).
What are the parts of the Geosphere?
Earth’s interior structure
Early in Earth’s history, the sorting of material by compositional (density) differences resulted in the formation of 3 layers.
- Crust
- Mantle
- Core
Define the crust
Earth’s relatively thin, rocky outer skin; continental (land) and oceanic (oceans).
Describe the Oceanic Crust
Roughly 7km thick and denser than the continental crust. It is composed of dark igneous rock called basalt.
Oceanic rocks are younger (180 billion years or
less) and denser (about 3.0g/cm3) than continental rocks.
Describe the Continental Crust
Is lighter than the oceanic crust and is roughly 70km thick in some mountainous regions (e.g Himilayays and Rockies).
The Continental Crust contains many different rock types. Although the upper crust generally consists of granitic rock called Granodiorite.
Continental rocks are lighter (about 2.7g/cm3) and rocks have been found to be over 4 billion years old.
Describe the Mantle
More than 82% of Earth’s volume is contained in the mantle. It can be divided into two parts; the lithosphere and asthenosphere.
It is a solid, rocky shell that extends to a depth of nearly 2,900km. Peridotite is the dominant type of rock in the upper mantle, which is richer in metals Mg and Fe than minerals found in either of the crusts.
Describe the lithosphere
Is found in the top part of the mantle (stiff) and consist of the entire crust and uppermost mantle forming the earth’s relatively rigid, cool outer shell.
Averaging about 100km thick.
Describe the asthenosphere
Beneath the stiff layer (lithosphere) is a comparatively weak layer called the asthenosphere reaching 350km deep.
The top portion of the asthenosphere has a temperature/pressure regime that results in a small amount of melting.
