HPU NCS2200 Earth Science for Elementary Education majors lecture on earth systems for unit 2 Lithosphere

1. 1
Chapter 1 – Earth Systems
Earth Science and the Environment (4th ed)
Thompson & Turk

2. 1.2 The Earth’s four spheres
►Geosphere – the solid earth
►Hydrosphere – the watery part of our planet
►Atmosphere – the gaseous layer above
►Biosphere – the living realm of organisms

3. Geosphere (Solid Earth) Formed by Accretion
A. Clouds of dust and gas form by accretion –
the attraction and accumulation of matter.
B. Material gets compressed and produces heat.
Heat melts heavy metals like Nickel and iron
C. The lighter elements are displaced and move to the surface
 density stratification – separation of materials by density

4. Inner Core – solid core of iron and nickel
under high pressure and temperature
Outer Core – liquid metals circulate
Around the solid inner core
Mantle – has two parts:
the upper mantle which is
made of rock that is pliable
the lower mantle which made of
solid rock that is very hot
Crust – thin outermost layer
of the earth made primarily
of silicates

5. 1.2 The Earth’s four spheres
►3 major layers of Earth’s Geosphere
 Dense metallic core
►Outer core liquid, inner core solid, 6000°C Ni-Fe
 Less-dense rocky mantle
►Changes with depth, some parts solid, others weak
and plastic-like, flowing slowly
 Even less dense surface crust
►Crustal material varies widely

6. Fig. 1.5, p.6

7. 1.2 The Earth’s four spheres
►Lithosphere – the crust and upper part of
mantle
 Average 100km thick
 Broken up into tectonic plates
 Plates float atop the weaker material
 7 major (and several minor) plates are in
constant motion

8. 1.2 The Earth’s four spheres
►Hydrosphere – all Earth’s water
 Oceans
 Glaciers
 Ground water
 Streams and lakes
 Atmosphere

9. Hydrosphere created by
Heating and Differentiation
► Hydrogen and Oxygen
released by volcanic
activity
► Water molecules form and
collect into vapor
► Vapor clouds cool and
condensed vapor falls as
rain – boils off immediately
► Vapor reforms into water
and the process continues
for millions of years
► Eventually surface cools
and water begins to collect
in rock basins

10. Fig. 1.8, p.7

11. Atmosphere Formed by heating and differentiation
Step 1.
Primordial
(ancient) gases
Lost to space
Due to solar
winds
Step 2. Volcanic venting &
Icy comets release carbon
monoxide (CO), carbon dioxide(CO2),
ammonia (NH4), methane (CH4) and
water vapor(H2O)
Step 3. Steady additions of gases
From volcanoes builds up the volume
Of atmosphere
Step 4.
Blue Green
algae convert
Carbon dioxide
to oxygen

12. 1.2 The Earth’s four spheres
►Atmosphere – the gas layer surrounding the
solid Earth
 Mixture of N, O, CO2, Ar, other gases
 99% in 1st 30km
 Acts as filter & blanket, and as heat transport
medium

13. 1.2 The Earth’s four spheres
►Biosphere – zone of living things
 Water, land, air all contain life
 Life is affected by the environment
 Life also alters the environment

14. Fig. 1.4, p.5

15. 1.3 Earth Systems
►Systems – an assemblage/combination of
interacting components forming a complex
whole
 i.e.: the human body, a bacterium, an
ecosystem
 Each “sphere” is a system

16. 1.3 Earth Systems
►Spheres are subdivided into component
systems
 Surface systems – mainly solar powered
►Mass and energy both move
►Chemical reactions change materials
 Internal systems – radioactively powered
►Spheres also linked into conjoined
subsystems

17. 1.5 Threshold and feedback effects
►Threshold effect – slow or no initial change
to environmental change
 When threshold point is passed, change
becomes rapid
►Feedback mechanism – one change affects
another system component, amplifying
original effect

18. Fig. 1.9, p.8

19. Study of Earth’s Systems
►Planets are active, dynamic and in
continuous state of change.
►Planetary changes are driven by complex
interactions among the individual systems.
 Earth’s systems consist of
►Geosphere
►Hydrosphere
►Atmosphere
►Biosphere

20. Earth Systems
► A system is any assemblage or combination of
interacting components that form a complex
whole.
► Systems are driven by matter and energy.
► Larger systems are composed of many smaller
systems
► The size of systems can vary dramatically.

21. Changes to systems
► Changes can occur to systems in two ways
 Events can occur slowly but become significant over
long periods of time
►Observation of these type of changes gave birth to the
gradualism or uniformitarianism principles.
 Improbable events can occur regularly
►These more catastrophic events occurred between periods of
relative tranquility and gave birth to the principle of
catastrophism – huge events that change the course of
Earth’s history

22. Changes to systems
► Systems have parameters under which they
operate
► Changes to those parameters cause changes to
the system
► Slow changes may appear to have no effect until a
threshold level is reached
► Once the threshold level is breached changes to
the system can occur in rapid and dramatic ways
► Example: ice melting

23. Changes to systems
► Because systems are complex interactions of
individual parts changes to one part may cause
changes to another part which may cause
increased changes to the first part – HUH????
 Its called a feedback mechanism it occurs when a
small change to the system affects another
component of the system which amplifies the original
effect which perturbs the system even further –
example albedo and ice melt.

24. Human Impact
► Humans are a part of the complex system of the
biosphere
► Through increased numbers we have had an
impact on the earth’s systems
► Through increased technology we have had an
impact on the earth’s systems
► Will the system continue to function as it has or
will the human impact eventually “break” the
system?
► We must first understand the systems to
determine the extent to which we are affecting
those systems