ENVS10001 Lecture Notes - Lecture 1: San Andreas Fault, South American Plate, Mariana Trench
17 May 2018
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NATURAL ENVIRONMENTS STUDY NOTES
LARGE SCALE EARTH PROCESSES
Earth’s Interior
Plate Tectonic Theory (3 major concepts)
1. Lithosphere is divided into rigid segments – plates
2. Plates are constantly moving in relation to each other
3. Major structural features of the Earth are made by
processes at plate boundaries
• Major plates: Pacific, Eurasian, Australian-Indian,
African, Antarctican, north American + south American
• Plate motion: 2-10cm/y – slide across Asthenosphere driven by gravity (ridge pull/slab push)
and convection currents in the mantle
Plate Boundaries
Boundary
Movement
Features
Example
Divergent
• Plates move away from each other
• New lithosphere formed from magma
pushing through gap
Mid Oceanic Ridges (Sea
Floor Spreading)
Rift Valleys
Mid-Atlantic Ridge
Great East African Rift
Valley
Convergent
• Plates collide with each other
• Lithosphere is consumed – sites of
intense earthquakes, volcanoes and
metamorphism
Subduction Zones
Mountain building
(orogenies)
Andes (O-C)
Himalayas (C-C)
Mariana Trench (O-O)
Conservative
• Lithosphere neither created nor
destroyed
• Plates slide past each other along faults
Earthquakes
Volcanoes
Alpine Fault
San Andreas Fault
Crust Type
Age
Density
Depth
Oceanic
Younger
More
dense
3.0g/cm3
Thinner
5-10km
(a:7)
Continental
Older
Less
dense
2.7g/cm3
Thicker
25-50km
(a:35)
Closed matter system: a physical
system where matter doesn’t cross the
boundaries
•Water cycle, nutrient cycles –
nitrogen, phosphate
Open matter system: a system where
matter can cross boundaries, + has
external interactions
•
A farm, a city
Attributes: physical objects of an
environment (features)
Process: natural forces, which form,
shape or reshape an environment
Interaction: between attributes +
processes
Document Summary
Closed matter system: a physical system where matter doesn"t cross the boundaries: water cycle, nutrient cycles nitrogen, phosphate. Open matter system: a system where matter can cross boundaries, + has external interactions: a farm, a city. Process: natural forces, which form, shape or reshape an environment. Interaction: between attributes + processes: plate motion: 2-10cm/y slide across asthenosphere driven by gravity (ridge pull/slab push) and convection currents in the mantle. Movement: plates move away from each other, new lithosphere formed from magma pushing through gap, plates collide with each other, lithosphere is consumed sites of intense earthquakes, volcanoes and metamorphism. Conservative lithosphere neither created nor destroyed: plates slide past each other along faults.
