Welcome to Introductory and Environmental Geology EART 1006 010153

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Welcome toIntroductory and Environmental Geology
EART 1006 (010153)

• Lecture 1 Planet Earth and Geological Systems

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IEG TIMETABLE
Course Outline http//www.unisanet.unisa.edu.au/l
earn/UniSAnet-1/?PATH/Resources/10153/Introductor
yandEnvironmentalGeology/defaultCourseOutlin
e.htm
Lectures Monday, 2.10-1 pm Room
H1-35 and Wednesday 9.10-10 am P1-14 Practicals/Wo
rkshops START THIS WEEK! Students must attend
one practical session and one workshop session
each week. Session times are Practicals Mon
3-5pm Wed 2-4pm Fri 11am-1pm   Sol Bob Ian Wor
kshops Wed 10-12 Thurs 9-11am Thurs 1-3
Civil Eng (Bob) Environmental (Sol) Environmental
(Sol) All practical and workshop sessions will be
held in Room H1-20
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IEG FIELD WORK

• Field safety and conduct form Must be
  completed and handed in.
• Excursion 1- Hallett Cove
• Excursion 2 - Mannum

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IEG ASSESSMENT

• Course Statement http//www.unisanet.unisa.edu.au
  /learn/UniSAnet-1/?PATH/Resources/10153/Introduct
  oryandEnvironmentalGeology/defaultCourseOutl
  ine.htm
• (a) Hallett Cove excursion assessment. 15
• (b) Mannum excursion assessment. 15
• Students who have not attended excursions will
  not be eligible to submit assessment for
  excursions.
• (c) Quizzes (3 x 10) 30
• (d) Combined Theory/Practical Examination 40

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STAFF
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Textbook

• Earths Dynamic Systems
• Accompanying website http//wps.prenhall.com/esm_h
  amblin_eds_10/0,8010,837327-,00.html
• Popular Geoscience readings
• A Short History of Nearly Everything by Bill
  Bryson EXCELLENT READING!!!
• The map that changed the world. by Simon
  Winchester
• Krakatoa The Day the World Exploded August 27,
  1883. by Simon Winchester
• Telling Lies for God Reason vs Creationism by
  Ian Plimer
• Raging Planet Earthquakes, Volcanoes, and the
  Tectonic Threat to Life on Earth. by Bill McGuire
• Search Engines
• Google http//www.google.com/webhp?sourceidnavcli
  entclientREAL-tbieUTF-8
• Google Scholar http//scholar.google.com/advanced_
  scholar_search
• Google Images http//www.google.com/imghp?hlenta
  bwi

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Note Please do not print these powerpoint
presentations! Think Environmental
Sustainability save some trees Either download
and read them directly from a computer or make
your own notes in a separate book. They serve
only as a guide to lecture content which is
covered in more depth in the textbook. Listen and
make notes of topics that are emphasised in class
and do the revision questions on the accompanying
website. http//wps.prenhall.com/esm_hamblin_eds_1
0/0,8010,837327-,00.html
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Earth Compared to Other Planets

• The Solar System
• The inner planets
• Rocky planets near the Sun
• Mercury, Venus, Earth Mars
• The outer planets
• Giant gaseous planets
• Jupiter, Saturn, Uranus, Neptune
• Pluto, a small icy planet, furthest from the Sun

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Earth Compared to Other Planets

• Composition varies between the inner and outer
  planets
• Density reveals distinct differences
• The rocky inner planets have densities of 3 g/cm3
  more
• The gaseous outer planets have densities of 1.6
  g/cm3 or less

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Earth is the only rocky planet with

• Abundant liquid water at surface
• An atmosphere rich in oxygen
• Extensive outcrops of silica-rich rocks
• Bimodal distribution of surface elevations
• Plate tectonics
• Life (that we know of)
• A large moon
• A strong magnetic field

Why?
All of these factors (systems) control the
overall equilibrium state of Earths environment
and hence the evolution of life This topic
explored further in Terrestrial Atmospheric
Systems
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Earth

• A small blue planet
• The view from space is dominated by blue oceans
  and white clouds
• Continents vary from icy Antarctica to large
  desert regions like the Sahara
• Liquid water is an obvious feature
• Water keeps the Earths surface in a state of
  dynamic change
• Water supports life

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Earth

• Why on Earth?
• Water exists as a liquid between 0 and 100 oC
• Earths distance from the Sun allows all three
  states of matter to exist for H2O
• Water has led to life on Earth
• Living things have helped shape the Earth
• Photosynthesis -gt oxygen atmosphere
• What is driving Earths dynamic systems?

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Earth

• Internal Heat
• Produces changes in the Earths features
• Slow movement of lithospheric plates
• Sources of internal heat
• Radioactive decay
• Potassium, Uranium, Thorium are naturally
  occurring radioactive elements
• Decay releases heat energy
• Accretionary heat from the Earths formation

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Earths Outermost Layers

• The most dynamic portion of the Earth
• Atmosphere
• Thin gaseous envelope surrounding Earth
• Hydrosphere
• Water layer dominated by the oceans
• Biosphere
• All living things on the planet
• Lithosphere
• Rocky outer shell

http//www.ucar.edu/learn/images/layers.gif
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The Atmosphere

• Insignificant fraction of Earths total mass
  (lt0.01)
• Moves easily, interacts with oceans and
  landmasses
• Circulation patterns are evident from space
• Solar heat drives this circulation
• Evaporation and precipitation of water play a
  role in circulation

http//www.astrosurf.com/lombry/meteo-atmosphere.h
tm
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The Atmosphere

• Composition is unique in our solar system
• 78 nitrogen
• 21 oxygen (not present in early atmosphere)
• Minor amounts of carbon dioxide, argon and water
  vapor
• Formation of limestone (CaCO3) in the ocean has
  trapped large amount of CO2

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The Hydrosphere

• Total mass of water on or near the Earths
  surface
• Covers 71 of Earths surface
• 98 in oceans
• 2 in glaciers, groundwater, lakes and streams
  (fresh water)
• The presence of water moderates climates and
  shapes the Earths surface

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The Biosphere

• All life on Earth
• Animals plants on land, in the sea and air
• Microorganisms, the most common form of life
• Forms a narrow zone near the Earths surface

http//www.geog.uni-heidelberg.de/ttavk/weltkarte
n/globen/1997-1998-biosphere-Nasa.jpg
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The Biosphere

• The diversity of life
• 1.6 million known species
• insects account for over one-half
• mammals only 4000 species (0.025)
• 30 million or more may exist
• Local environment controls distribution
• Temperature, pressure chemistry
• Wide range of environmental conditions

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The Biosphere

• Why are geologists interested in the biosphere?

• The biosphere as a geologic force
• Current atmosphere produced by biosphere O2-rich
• Ocean composition influenced by biosphere -
  precipitation of calcium carbonate
• Fossils fuels
• Fossils record past Earth environments
• Current living species account for only 10 of
  known species throughout geologic history

http//seekers.100megs6.com/PlanetEarth3.htm
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Earths Internal Structure

• The solid Earth has a layered structure
• Layers defined by composition and physical
  properties
• Compositional layers
• crust - mantle - core
• Physical layers
• lithosphere - asthenosphere - mesosphere - outer
  core - inner core

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Compositional Layers

• Crust
• Outermost compositional layer
• Definite change in composition at the base of the
  crust
• Crust may be divided into 2 types
• Continental crust
• Oceanic crust

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Compositional Layers

• Crust
• Continental crust
• Thicker than oceanic crust - up to 75 km
• Less dense - 2.7 g/cm3
• Strongly deformed
• Much older - may be billions of years old

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Compositional Layers

• Crust
• Oceanic crust
• Thinner than continental crust - about 8 km
• More dense - 3.0 g/cm3
• Comparatively undeformed
• Much younger - lt 200 million years old
• Composed of basalt

Basalt
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Compositional Layers

• Mantle
• Largest layer in the Earth
• 2900 km thick
• 82 by volume
• 68 by mass
• Composed of silicate rocks with abundant iron and
  magnesium
• Density ranges from 3.2 to 5 g/cm3
• Fragments found in some volcanic rocks

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Compositional Layers

• Core
• Central mass about 7000km in diameter
• Average density of 10.8 g/cm3
• 16 by volume, 32 of mass
• Indirect evidence of composition
• Metallic iron

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Physical Layers

• Lithosphere
• Crust upper portion of the mantle
• Solid rigid
• Thickness ranges from 10 km beneath oceans to 300
  km in continental areas

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Physical Layers

• Asthenosphere
• Upper layer in the mantle
• Temperature and pressure combine to allow rock to
  partially melt
• Rocks are soft and plastic
• Flow slowly, easily deformed
• Boundary with lithosphere is defined by
  mechanical properties, not composition

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Physical Layers

• Mesosphere
• The region between the asthenosphere and the core
• Higher pressure offsets higher temperatures
• Rocks gain rigidity and mechanical strength

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Physical Layers

• Outer Core
• 2270 km thick
• Liquid, flows
• Flow creates magnetic field
• Inner Core
• 1200 km thick
• Solid

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Majors Features of the Continents

• Shields
• Large, flat areas of highly deformed crystalline
  rock - most more than 1 billion years old e.g.
  Pilbara NW Australia
• Basement complex
• Stable platforms
• Areas where the basement complex is covered by
  layered sedimentary rocks e.g. Central Australia
• Folded Mountains
• Young, linear regions of deformed rocks e.g.
  Indonesia

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Mapping
In February 2000, astronauts on the space shuttle
using imaging radar revolutionized mapmaking. In
just nine days, they collected the data for the
most accurate topographic map ever made of much
of the planet. (Courtesy of NASA/JPL/Caltech)
The shuttle radar topographic map shows the
dramatic difference between the new data (30 m
resolution on the left) and the best existing
data (on the right) for the tropical rain forests
of central Brazil. (Courtesy of NASA)
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Major Features of the Oceans

• Oceanic Ridge
• 70,000 km long continuous feature
• Broad ridge, highly fractured with a central rift
  valley
• Fractures, perpendicular to the ridge, are common
• Trenches
• Lowest areas on Earth
• Adjacent to chains of volcanoes

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Mapping the Seafloor

• Virtually nothing of the sea-floor was known
  until after WWII

A completely new way to make global maps of the
seafloor is carried out by an orbiting spacecraft
instead of a ship. The satellites use radar to
carefully map the elevation of the sea surface.
These maps show that the surface of the ocean
bulges upward and downward, mimicking the
topography of the underlying ocean floor.
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Major Features of the Oceans

• Abyssal Floor
• Abyssal hills - small hills up to 900 m high
• Cover 80 of ocean floor
• Most common landform on Earth
• Abyssal plains - smooth area adjacent to
  continents
• Sediment covered abyssal hills
• Seamounts
• Isolated peaks of submarine volcanoes

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Major Features of the Oceans

• Continental Margins
• Continental shelf - submerged portions of
  continents
• Part of the continent, not the ocean basin
• Arial extent has varied throughout geologic
  history
• 11 of continents are submerged today
• Continental slope
• Long slope from continents to ocean basin

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The Ecosphere

• Ecosphere
• A closed, self-contained system
• Only external input is energy
• Mass remains the same
• Lithosphere, hydrosphere, atmosphere biosphere
• Spheres interact to form an interconnected
  dynamic system

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End of Chapter 1
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Chapter 2 - Systems

• A system defined
• A group of interdependent materials
• e.g., a home plumbing system
• A system has a boundary
• Matter energy may interact within the system,
  and with the surroundings
• Work may be done by or to the system

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Systems

• Dynamic systems - a system in which matter
  energy react
• Closed systems - a system that only exchanges
  energy across its boundary
• Open systems - a system that will exchange both
  matter and energy across its boundary
• Most geologic systems are open
• Would you define the Earth as a whole as an open
  or closed system?
• Both. Most of the time it is closed with only
  solar radiation (energy) being exchanged across
  its boundary with space but there is also a
  continual downfall of space-dust and infrequently
  large meteorites as well as a continual erosion
  of lighter elements (H2, He) from our atmosphere

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Geologic Systems

• The Earth is a system
• Ecosystem model (chapter 1)
• Many subsystems
• Nearly closed
• Small mass of meteorite and space dust input
• Solar energy enters the system
• Produces reactions within the system
• Causes matter to flow react

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Geologic Systems

• Subsystems
• A river system
• Open or closed?
• Part of the larger hydrologic system
• Interacts with other subsystems
• Groundwater
• Oceans
• Atmosphere

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Systems
(B) Open systems, such as a river, exchange
energy and matter. In a river, water and sediment
are collected from the dranage area and flow
through the system to the sea. Most geologic
systems are open systems. (Photo by Ken Hamblin)
(A) A closed system, such as a cooling lava flow,
exchanges only radiant heat. Here, heat from the
lava is lost to the atmosphere. (Photo by Ken
Hamblin)
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The Hydrologic System

• The complex cycle through which water moves
• Global scale
• Basic components
• Evaporation
• Precipitation
• Runoff
• Infiltration
• Evapotranspiration

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Hydrologic Subsystems

• Atmosphere Ocean System
• Oceans are reservoirs for liquid water
• Water vapor is transient in the atmosphere
• Climate system is controlled by ocean-atmosphere
  interactions
• Solar heating is driving force behind circulation

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Hydrologic Subsystems

• River Systems
• Surface drainage returns most precipitated water
  back to the ocean
• Water flows rapidly through this system
• Only accounts for 0.0001 of Earths water
• Effective system for transport of weathering
  products

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Tectonic Systems

• Plate Tectonics
• A unifying theory that explains the internal
  dynamics of the Earth
• The study of processes that form and deform the
  Earths crust
• Delineation of discrete lithospheric plates
• Developed in the mid-1960s, but pieces were
  known much earlier

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Tectonic Systems

• Driving Forces
• Earths internal heat source
• Radioactive decay residual heat
• Heat transfer by convection
• Hot, less dense material rises from the mantle
• Cool, more dense material descends from the crust

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To Do List

• Go to the Earths Dynamic Systems website at
  http//wps.prenhall.com/esm_hamblin_eds_10/0,8010,
  837327-,00.html
• Create your own profile by clicking on profile
  and filling in your details. Do not send the
  results to me as this will not form part of your
  assessment however it will be a very useful way
  of reviewing what has been covered in lectures
  and many of the quiz questions will come directly
  from the textbook.
• Follow the links and complete the following for
  Chapters 1 2
• You can do them over again until you get them all
  right it shouldnt take you long (lt1hr)
• GO TO IT!!