Download Volcanoes and Igneous Activity Earth

3/8/2017
Prepared by
Dr. Khayyun A. Rahi
Department of Environmental
Engineering
What is Geology?
OSU
School of Geology
Geology - study of the Earth
Physical Geology - nature of Earth, materials
composing Earth, processes that shape the
structure and appearance
Historical Geology - origin of Earth,
development of Earth through time
Environmental Geology - application of geologic
information to problems created by human
habitation of the physical environment
Engineering Geology is the application of the
geologic sciences to engineering
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Human Environmental Impact
• Depends on how
much of Earth’s
resources are
consumed
• Depends on
generated waste
quantity in the
process of resource
consumption
Figure 1-2b Earth Affects People; People
Change Earth People influence Earth such as
by damming rivers to control floods and
generate power.
How People and Earth Interact
Some Important Factors to Consider:
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Human Population
Resource Consumption
The Technology Factor
Earth’s Impact on
People
Figure 1-5 More People Are Living in
Cities More than half the inhabitants of Earth
now live in cities, and proportion of urban
dwellers is increasing.
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IPAT Equation
• I=P+A+T
• I = Influence
• P = Population
• A = Affluence
• T = Technology
Qualitative with no exact numbers
IPAT Equation…CONT.
• Environmental impact (I) may be expressed
in terms of resource depletion or waste
accumulation;
• Population (P) refers to the size of the human
population;
• Affluence (A) refers to the level of
consumption by that population;
• and Technology (T) refers to the processes
used to obtain resources and transform them
into useful goods and wastes.
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IPAT Equation Consequences
• Wealthy developed countries use far more
resources and cause more pollution per
capita than poorer countries
• Average American consumes 35x resources
of the average Indian
• I = P for less-developed countries –
environmental problems more obvious
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Sustainability
• Critical concept in
environmental studies
and is one that we will
use as a measure
throughout the text
materials
• Capable of being
continued with
minimal long-term
effect on
the environment.
Figure 1-3 Many Natural Resources Can Be
Sustained On farms like this experimental
agricultural station in Peru, methods are carefully
chosen to help maintain soil quality.
A View of Earth
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Earth is a planet that is small and
self-contained.
Earth’s four spheres are:
1. Hydrosphere
2. Atmosphere
3. Biosphere
4. Geosphere
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A View of Earth From Apollo 17
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Earth as a System
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Earth is a dynamic planet with many interacting
parts or spheres.
Earth system science:
 Aims to study Earth as a system composed of
numerous interacting parts, or subsystems
 Employs an interdisciplinary approach to
solve global environmental problems
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Earth as a System, Continued
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What is a system?
 Any size group of interacting parts that form
a complex whole
 Open vs. closed systems
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Types of Systems
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(a) A closed system is one that
exchanges only energy with its
surroundings.
(b) An open system can
exchange matter as well.
If a reservoir is an open
system, its size will be affected
by the relative amounts of flux
in and flux out of the system.
If transfers of energy and
matter into and out of an open
system are about the same,
the system is said to be in a
steady state (Figure 1-11b).
Figure 1-11 Reservoirs and Flux
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Earth as a System, Continued
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Cycles in the Earth System
 Hydrologic cycle
 Rock cycle
An interface is a common boundary where
different parts of a system come in contact and
interact.
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The Interface between the
Hydrologic and Rock Cycles
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Earth as a System
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The Earth system is powered by the Sun that
drives external processes in the following:
 Atmosphere
 Hydrosphere
 At Earth’s surface
The Earth system is also powered by Earth’s
interior heat.
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Early Evolution of Earth
Origin of planet Earth
 Most researchers believe Earth and other
planets formed at essentially the same time.
 Nebular hypothesis
 Solar system evolved from an enormous rotating
cloud called the solar nebula
 Composed of hydrogen and helium
 Nebula began to contract about 5 billion years ago.
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Early Evolution of Earth,
Continued
Origin of planet Earth
 Nebular hypothesis
 Assumes a flat, disk shape with the protosun (preSun) at the center
 Inner planets begin to form from metallic and
rocky substances.
 Larger outer planets began forming from
fragments of ices (H2O, CO2 , and others).
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The Nebular Theory
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Early Evolution of Earth
Formation of Earth’s layered structure
 Metals sank to the center.
 Molten rock rose to produce a primitive
crust.
 Chemical segregation established the three
basic divisions of Earth’s interior.
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Earth’s Internal Structure
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Layers defined by composition:
 Crust
 Mantle
 Core
Layers defined by physical properties:
 Lithosphere
 Asthenosphere
 Mesosphere
 Inner and outer core
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Earth’s Layered Structure
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The Face of Earth
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Earth’s surface:
 Continents
 Oceans
Continents:
 Mountain belts
 Most prominent feature of continents
 The stable interior
 Also called a craton—composed of shields and
stable platforms
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Earth’s Mountain Belts, Stable
Platforms, and Shields
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The Face of Earth

Ocean basins:
 Continental margins
 Includes the continental shelf, continental slope,
and the continental rise
 Deep-ocean basins:
 Abyssal plains
 Oceanic trenches
 Seamounts
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The Face of Earth, Continued
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Ocean basins:
 Oceanic ridge system
 Most prominent topographic feature on Earth
 Composed of igneous rock that has been fractured
and uplifted
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•.
•Continental Slope: Steep incline (ocean floor).
•Abyssal Plain: Smooth nearly flat area of the ocean floor.
•Continental Shelf : Gently , slopping shallow area.
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Volcanic Island: A volcano above the water line
Mid-Ocean Ridge : Ridge line in the middle of the ocean.
Deep Ocean Trench: Steep -sided canyons.
Seamount : Underwater volcano
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Rocks and the Rock Cycle
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Basic rock types:
• Igneous rocks
 Cooling and solidification of magma (molten rock)
 Examples include granite and basalt.
• Sedimentary rocks
 Accumulate in layers at Earth’s surface
 Sediments are derived from weathering of preexisting
rocks
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Granite (an Igneous Rock) in
Yosemite National Park, CA
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Rocks and the Rock Cycle
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Basic rock types:
• Sedimentary rocks
 Examples include sandstone and limestone.
• Metamorphic rocks
 Formed by “changing” preexisting igneous, sedimentary,
or other metamorphic rocks
 Driving forces are heat and pressure.
 Examples include gneiss and marble.
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Sandstone (a Sedimentary Rock)
in Utah
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Rocks and the Rock Cycle
The rock cycle: one of Earth’s subsystems
• The loop that involves the processes by which one rock
changes to another.
• Illustrates the various processes and paths as Earth
materials change both on the surface and inside the
Earth
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The Rock Cycle
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End of Lecture 1
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