The Earths Interior Composed of 4 layers Crust Mantle Outer Core
Inner Core Crust Temperature: Over 175 degrees Celsius Topmost layer of the Earth
Relatively cool Made of rock 2 types of crust Oceanic (4-7 km thick) Continental (20-40 km thick) Mantle Temperature: Over 1250 degrees Celsius
Makes up about 80% of the Earths volume ~ 2900 km thick Outer mantle rocks Inner mantle plastic Core Temperature: Over 6000 degrees Celsius Outer core liquid
Pressure from the mantle & crust do not allow the metals in the outer core to become gasses Inner core solid Pressure from the mantle and crust do not allow the metals to become liquid Plate Tectonics The Earths lithosphere is made up of 7 tectonic plates Plate tectonics the movement of these lithospheric plates Why do the plates move? One theory suggests that plates move due to the convection currents in the asthenosphere (plastic inner portion of the mantle) Divergent Plate Boundaries
2 plates move apart Magma fills the gap created from this movement Magma cools as it reaches the Earths surface creating rift valleys Convergent Plate Boundaries
Oceanic plates dive beneath continental or oceanic plates (called subduction) Creates deep ocean trenches Wall diving- coral reefs form over time on the walls of deep sea trenches.Many are thousands of feet deep. Convergent Plate Boundaries
Mountains form at the convergent plate boundaries as magma from the mantle rises, pushing continental crust upward Convergent Plate Boundaries
Volcanoes form at the convergent plate boundaries as magma rises to the surface and cools Transform Fault Boundaries
Plates move past each other at cracks in the lithosphere (called faults) Transform fault boundary horizontal movement between two plates Earthquakes Occur at plate boundaries
Plates slide past each other creating pressure Rocks break along the fault line Energy is released, called seismic waves San Andreas Fault Focus = point of earthquake origination
Epicenter = point on the Earths surface directly above the focus Energy from an earthquake
Energy is released in the forms of waves P wave: Primary or longitudinal waves originate from the focus & move quickly through rock.These are the first waves to be recorded S wave: Secondary or transverse waves originate from the focus & moves more slowly through rock. Surface waves: move across the earths surface, causes building to collapse Earthquake Measurement
Seismograph Records data about P, S and surface waves Used to locate the epicenter of an earthquake Richter scale Measures energy released at the epicenter of an earthquake (in magnitude) Each step up in magnitude represents a 30-fold increase in energy released! Volcanoes Volcanoes result from openings or vents in the Earths surface Magma reaches the surface through these vents When magma reaches the surface it changes physically and is called lava Shield Volcano Formed from fluid lava, rich in iron
Shield volcanoes are large Mauna Loa in Hawaii Composite Volcano Made of alternating layers of lava, ash and cinders.
Magma is rich in silica and thick Large with steep slopes Cinder Cone Large amounts of gas are trapped in the magma causing violent eruptions Active for short periods of time Minerals & Rocks Minerals: Rocks:
naturally occurring, inorganic substances (inorganic = does not contain Carbon) can be expressed by a chemical formula Quartz SiO2 (silicon dioxide) Rocks: Composed of minerals Types of Rock Igneous Sedimentary Metamorphic
Formed when magma or lava cools and hardens Magma forms intrusive igneous rock Lava forms extrusive igneous rock Sedimentary Formed when rock particles, plant and animal debris are carried away by water, redeposited, then fused together Metamorphic Rock particlesare fused together by pressure beneath the Earths surface Determining the age of rocks
Two ways to determine the age of a rock: Superposition determine the age based on layers, older rocks are on the bottom, newer ones on top Radioactive dating The Rock Cycle Weathering and Erosion
Two types of weathering Physical Breaks rocks into smaller pieces, chemical composition does not change May be caused by ice or plants Chemical Changes the chemical composition of rocks May be caused by oxidation or acid rain Erosion Erosion: the process of loosening and removing sediment
Caused by water, glaciers, wind Deposition Occurs when loose sediment is laid down
Causes river beds to widen and deltas to form. Important Elements Oxygen most abundant element in the Earths crust
Nitrogen most abundant element in the atmosphere Iron most abundant element in the core