Plate Tectonics Why Continents and Ocean Basins Exist
Topics Density Structure of Earth Isostasy Sea-Floor Spreading Mechanical Structure of Earth Driving Mechanism of Plate Tectonics Lithospheric Plate Interactions Plate Tectonics and the Depth of the sea floor
Topics Density Structure of Earth Isostasy Sea-Floor Spreading Mechanical Structure of Earth Driving Mechanism of Plate Tectonics Lithospheric Plate Interactions Plate Tectonics and the Depth of the sea floor
Mechanical Structure of Earth
Mechanical Structure of Earth A different way to view the structure of Earth
To understand how the crust moves, scientists view the structure of Earth in a different way
To understand how the crust moves, scientists view the structure of Earth in a different way Geologist use this structure because the crust does not move by itself
To understand how the crust moves, scientists view the structure of Earth in a different way Geologist use this structure because the crust does not move by itself The crust and the upper mantle move as a unit
Review
Review The density structure of Earth is based on two criteria: 1. Density 2. Composition
Mechanical Structure of Earth
Mechanical Structure of Earth Use this structure when discussing plate motions
Mechanical Structure of Earth Use this structure when discussing plate motions Structure based on two criteria:
Mechanical Structure of Earth Use this structure when discussing plate motions Structure based on two criteria: 1. Strength
Mechanical Structure of Earth Use this structure when discussing plate motions Structure based on two criteria: 1. Strength 2. Viscosity
Mechanical Structure of Earth
Mechanical Structure of Earth The mechanical structure of Earth has four layers:
Mechanical Structure of Earth The mechanical structure of Earth has four layers: 1. Lithosphere
Mechanical Structure of Earth The mechanical structure of Earth has four layers: 1. Lithosphere 2. Asthenosphere
Mechanical Structure of Earth The mechanical structure of Earth has four layers: 1. Lithosphere 2. Asthenosphere 3. Mesosphere
Mechanical Structure of Earth The mechanical structure of Earth has four layers: 1. Lithosphere 2. Asthenosphere 3. Mesosphere 4. Core
Mechanical Structure of Earth Structure of Earth based on strength and viscosity 1. Lithosphere --- outside 2. Asthenosphere 3. Mesosphere 4. Core --- inside
Mechanical Structure of Earth Structure of Earth based on strength and viscosity 1. Lithosphere --- outside 2. Asthenosphere 3. Mesosphere 4. Core --- inside
Mechanical Structure of Earth
Lithosphere
Lithosphere Includes all of the crust and the upper mantle
Lithosphere Includes all of the crust and the upper mantle Averages 80 km thick
Lithosphere Includes all of the crust and the upper mantle Averages 80 km thick Relatively strong compared to the asthenosphere
Lithosphere Includes all of the crust and the upper mantle Averages 80 km thick Relatively strong compared to the asthenosphere Tends to resist stress to the point of fracture
Lithosphere Includes all of the crust and the upper mantle Averages 80 km thick Relatively strong compared to the asthenosphere Tends to resist stress to the point of fracture Relatively high viscosity
Lithosphere Includes all of the crust and the upper mantle Averages 80 km thick Relatively strong compared to the asthenosphere Tends to resist stress to the point of fracture Relatively high viscosity Relatively low temperature
Lithosphere
Lithosphere Includes all of the crust and the upper mantle Averages 80 km thick Relatively strong compared to the asthenosphere Tends to resist stress to the point of fracture Relatively high viscosity Relatively low temperature
Isostasy The lithosphere floats on the asthenosphere
Asthenosphere
Asthenosphere Underlies the lithosphere
Asthenosphere Underlies the lithosphere Averages 300 km thick
Asthenosphere Underlies the lithosphere Averages 300 km thick Relatively weak compared to the lithosphere
Asthenosphere Underlies the lithosphere Averages 300 km thick Relatively weak compared to the lithosphere Tends to flow when stressed
Asthenosphere Underlies the lithosphere Averages 300 km thick Relatively weak compared to the lithosphere Tends to flow when stressed Relatively low viscosity
Asthenosphere Underlies the lithosphere Averages 300 km thick Relatively weak compared to the lithosphere Tends to flow when stressed Relatively low viscosity Relatively high temperature
The asthenosphere is the source of magma that forms the sea floor
The mesosphere is the largest part of Earth
The mesosphere is the largest part of Earth The mesosphere is hotter but more viscous than the asthenosphere
The mesosphere is the largest part of Earth The mesosphere is hotter but more viscous than the asthenosphere The outer core is molten Fe
The mesosphere is the largest part of Earth The mesosphere is hotter but more viscous than the asthenosphere The outer core is molten Fe The inner core is solid Fe
The Driving Mechanism of Plate Tectonics
Next The Driving Mechanism of Plate Tectonics
Definition Back
Definition Viscosity - measure of the resistance to flow Back
Definition Viscosity - measure of the resistance to flow For example, water has a low viscosity, it flows easily Back
Definition Viscosity - measure of the resistance to flow For example, water has a low viscosity, it flows easily Glass has a high viscosity, it strongly resists flow Back
Mechanical Structure of Earth