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The Four Great Realms
Lithosphere - processes associated with the solid earthHydrosphere - processes associated with waterAtmosphere - processes associated with the gases that envelope the earthBiosphere - processes that involve living organisms
Inside the Earth
Lithosphere
Origin• Cooling off and
solidification
• Thermal convection currents
Present• Consists of soil, rocks
and minerals
• Contains landforms– Hills, mountains, valleys
• Temperature increases up to 15C/km deep
Composition
• Crust
• Mantle
• Core
The Crust
• Outer layer• 5-100 km thick• temperature ranges
between 10 to 20C/km deep
• 2 types of crust– Oceanic (very dense,
made of basalt)– Continental (less
dense, made of granite)
Oceanic and Continental Crust
Types of Crust
Continental• Predominantly granitic
• Granite or sialic rock--- richer in aluminum and silicon
Oceanic• Basaltic
• Basalt or simatic rock---richer in magnesium and silicon
The Mantle
• Middle layer• Very thick layer• Temperature at the
core-mantle boundary 3000C
The Core• Made mostly of iron
• 1/3 of the earth’s mass
• Very hot about 4000C
Earth’s Layers
• How are the earth’s layers similar to an egg?
• Shell=crust• Egg white=mantle• Yolk=core
Physical Structure of the Earth(5 Layers)
• Lithosphere- rigid outer layer (crust)
• Asthenosphere- solid rock that flows slowly (like hot asphalt)
• Mesosphere- middle layer
• Outer Core- liquid layer
• Inner Core- solid, very dense
Tectonic Plates• Earth’s crust is broken into about 19
pieces
• These plates move on top of the asthenosphere
Atmosphere
The earth’s life giving blanket
Origin of the Atmosphere
• Volcanic Eruptions• Extensive period of
global volcanic activity
• Reducing atmosphere
The present atmosphere
• Air: invisible, odorless mixture of gases and suspended particles
• Aerosols• Water vapor
Layers of the atmosphere
• 4 layers• troposphere,
mesosphere, thermosphere stratosphere
Troposphere
• the layer that is closest to the surface of the earth
• It’s elevation ranges from 0 to 10 km
Stratosphere
• sits on top of the troposphere
• It’s elevation ranges from 10 km to around 25 km
• contains the ozone layer, which protects us from harmful sunlight
Mesosphere
• Middle layer above the stratosphere
• It’s elevation ranges from 25 to 100 km
• Temperature diminishes with altitude
• Minimu tepmt is about -80C
Thermosphere
• highest layer of the atmosphere
• It’s height ranges from 100 to 400 km
• where most small meteorites burn up
• Temperature is very high• the location in the
atmosphere that the northern lights occur (aurora borealis)
Composition of Air
• There are many different types of gasses in the atmosphere
• They include nitrogen, oxygen, argon, carbon dioxide and other noble gasses
• The gas that is most abundant is nitrogen
Hydrosphere
• Liquid part of the earth– oceans– ice caps– lakes– rivers– underground aquifers– soil water– atmosphere– living organisms
Hydrosphere
Origin
• Occasional raindrops
• Global deluge of rains
• Formation of oceans, rivers, lakes and underground water tables
Present
• Moving, dynamic mass of liquid
• Solar energy drives hydrologic cycles
• Essential for life: univesal solvent
Earth’s water budget - water cycle
– 97.4% salt water - only 2.6% fresh water– Of that 2.6%, over 80% is in ice caps &
glaciers– 0.59% is in ground water– <0.001% in atmosphere
• Remainder in lakes, soil water, rivers and organisms (in decreasing order of storage)
Global Hydrologic Cycle(key component of the global climate
system)
Freshwater as a resource
• Renewable through evaporation from the seas and precipitation (solar powered)
• Demands for freshwater include:– Human consumption (10%)– Irrigation (70%)– Industry (20%)
• Demands increase with increasing population
• Unequal distribution of freshwater
Human impacts on water cycle
• Global warming - may disrupt rainfall patterns
• Withdrawing of ground water faster than it can be replenished
• Pollution• Deforestation• Increased demand• Inequity of use
Sustainable use of freshwater
• Methods of increasing freshwater supply– Rain barrels– Dams and reservoirs– Water purification– Desalination ($3/4,000L)– Storm water management
Summary
• From the atmosphere came the hydrosphere, just as the atmosphere came from the lithosphere
• For about 2 BY, the 3 spheres interacted • And from the interaction, about 4BY
evolved the biosphere