esci111: introduction to physical geology & physical geography dr. francis o. odemerho alumni...
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ESCI111: Introduction to Physical Geology ESCI111: Introduction to Physical Geology & Physical Geography& Physical Geography
Dr. Francis O. Odemerho Alumni Hall, Room 1402
Tel: (618) 650-2097Email: [email protected]
Website: http://www.siue.edu/~fodemer/esc111.htm
Topic 1: Introduction to Physical Topic 1: Introduction to Physical GeologyGeology
INTRODUCTION- The Science of Geology and Scope of Physical Geology - Importance of Physical Geology - Geologic Systems
SOME HISTORICAL NOTES ABOUT GEOLOGY - Catastrophism- Uniformitarianism
EARTH AS A PLANET- The Solar System - Terrestrial Planets - Unique Features of Planet Earth - Spheres of the Planet Earth - Earth’s Moon
The science & Scope of Physical GeologyThe science & Scope of Physical Geology
Geology is the scientific discourse of planet Earth
It is divided into 2 broad areas:Physical Geology:
- examines the materials making the earth - and geologic processes operating on or
beneath the earth surfaceHistorical Geology:
- chronology of geologic events - focuses on asking the when questions
Geology Sub-fieldsGeology Sub-fieldsPlanetary Geology Tectonics
Geomorphology Paleontology
Seismology Paleogeography
Geophysics Stratigraphy
Oceanography/Ocean Science Geochronology
Environmental Geology Archeological Geology
Economic Geology Biogeosciences
Petrology Engineering Geology
Geochemistry Forensic Geology
Mineralogy History of Geology
Structural Geology Hydrogeology
Glacial Geology Medical Geology
GEOLOGY: Subfields and Related DisciplinesGEOLOGY: Subfields and Related Disciplines
The Two Broad Fields of GeologyThe Two Broad Fields of Geology
Physical Geology Historical GeologyGeomorphology Paleontology
Seismology Paleogeography
Geophysics Stratigraphy*
Oceanography Geochronology
Environmental Geology
Economic Geology
Petrology
Geochemistry
Mineralogy
Structural Geology
Glacial Geology
Importance of Physical GeologyImportance of Physical Geology
Meets SIUE general education requirement
Helps our understanding of nature and how the earth works
Helps us in the discovery of earth’s natural resources:
- water and soil resources- mineral ores and deposits
- building materials - oil fields for fossil fuels (Petroleum, Coal and Natural Gas), etc, etc
Importance of Physical GeologyImportance of Physical Geology
Offers us key information on the causes and effects of past climatic changes
Increases our environmental awareness and the recognition of potential geologic hazard zones
Serves as useful guide in planning construction works, environmental planning and management
Some Historical Notes About GeologySome Historical Notes About Geology
Writings about earth’s materials and processes started more than 2300 years ago, among Greco-Roman scholars
Aristotle believed that: - rocks were created under the influence of stars- earthquakes are caused by over-pressured
ground air that escaped rapidly when heated up central fires
Aristotle’s authoritative posture thwarted the growth of geologic sciences
Some Historical Notes About GeologySome Historical Notes About Geology
School of Catastrophism:- Archbishop James Ussher in the mid-1600 claimed that the earth was created in 4004 B.C.
- This means that the earth is only 6000 years old
- This meant that all geologic structures were formed very rapidly within the last 6000 years rather than millions of years expected by geologists
- Such short earth history gave rise to the school of catastrophism that dominated geology during the 17th and 18th centuries
Some Historical Notes About GeologySome Historical Notes About Geology
- Catastrophists believe:
=> that landforms are produced by greatcatastrophic events that are no longer in operation today
=> that features such as mountains and canyons were produced by sudden and often
worldwide disasters like the Noah’s flood
=> in divine intervention and creationism in geology
Some Historical Notes About GeologySome Historical Notes About Geology
School of Uniformitarianism:- is to counter the teachings of the school of catastrophism by James Hutton in his book “Theory of the Earth” in the late 1700s
- He argued that the Earth has a long history withno vestige of a beginning & no prospect of an
end
Some Historical Notes About GeologySome Historical Notes About Geology
- He argued that physical, chemical & biological laws that operate today also operated in the past (i.e. the present is the key to the past)
- And that landforms are produced by geologic processes that act slowly and steadily (or uniformly) through time
John Playfair and Charles Lyell made the doctrine of uniformitarianism to be accepted by the scientific community and helped to remove religion from geology
Some Historical Notes About GeologySome Historical Notes About Geology
The Exploration of American West in the mid-1800s laid the foundation for the development of modern geology
Geologic TimeGeologic Time
Geologic time scale is developed using two basic methods:- Relative Dating Technique and- Absolute (Radiometric) Dating Technique
Relative dating involves the placement of rocks in their proper sequence of formation without knowing their actual age in years using simple rules like the principle of:- superposition- fossil succession- original horizontality and cross-cutting
Geologic TimeGeologic Time
Geologic TimeGeologic Time Based on relative dating techniques geologists worldwide
built the standard geologic column of earth history
The Geologic time scale is divided into two major Eons:
- Phanerozoic Eon (0 – 542 million years ago)
- Precambrian Eon (542million – 4.5 billion years ago):
- Proterozoic (542million - 2500million years ago)(First Multi-celled organisms)
- Achaean (2500million – 4000million yrs ago)(First One-celled organisms)
- Hadean (4000million – 4500 million years ago) (First One-celled organisms)
Geologic TimeGeologic Time The Phanerozoic Eon of time is divided into three major
Eras:
- Cenozoic Era- Mesozoic Era- Paleozoic Era
The Precambrian Era accounts for 88% of geologic time
Absolute dating determines the actual age of rocks using radiometric methods
The Earth is about 4.5 billion years old
The Nature of Scientific InquiryThe Nature of Scientific Inquiry
Science is based on the assumption that nature is orderly, consistent and predictable
Therefore, the goal of science is to:- discover the underlying pattern in nature- make general verifiable statements of relationships in nature - make predictions about what to or not to expect about nature
To achieve this goal, scientists make observations and collect measurable facts that help to explain any observable relationships in nature
The Nature of Scientific InquiryThe Nature of Scientific Inquiry
How and why things happen is explained using:- hypothesis which is a tentative or untested
explanations
- theory which is a well tested and widely accepted view that the scientific community agrees best explains certain observable facts
Hence, the scientific method involves:- the formulation of some form of hypothesis- the collection of data through observation and measurement
The Nature of Scientific InquiryThe Nature of Scientific Inquiry
- testing the data through some form of analysis to see if the data support the initial hypothesis
Some scientific discoveries may occur through logical reasoning alone
Once an hypothesis survives extensive scrutiny, it is elevated to the status of a theory
Paradigm – a theory that is held with a very high degree of confidence because it explains a large number of interrelated aspects of the natural world
Geologic SystemsGeologic Systems
The earth is a natural system in continuous motion
Geologic systems governed by natural laws make us to understanding how planet earth works
Hydrologic system and tectonic system are examples of geologic systems that help us to understand:- geologic change and their effects- geologic processes- structural features of our planets
Geologic SystemsGeologic Systems
A system is a set of interdependent objects or materials that work together with energy as a unit or a unified whole
A system helps us to understand how rainfall, runoff, landforms are related and function together as a unit
Natural systems are of two types:- Closed system (exchanges only heat, no new
matter) (Example: cooling lava flow)- Open system (exchanges both heat and materials)
Geologic SystemsGeologic Systems
Most geologic systems are open systems because energy and matter flow freely across system’s boundaries (Example: river system with rainfall from outside)
The river system receives matter like rain & snow from outside the system (input) and flows out of the system to the ocean (output)
It utilizes gravitational energy and kinetic energy and solar energy from the sun
Geologic Systems Geologic Systems
In general, geologic systems involve the flow of energy and the movement of matter
The transfer of matter and energy causes the system to change in order to establish a state of Equilibrium with the new surroundings
Some examples of subsystems of the geologic systems include:- The Hydrologic System- The Tectonic System, etc
The Hydrologic SystemThe Hydrologic System
It is a geologic system showing the pathways of water moving from:- the oceans- to the atmosphere- over the continents, and- back to the oceans
The flow of water across earth surface causes erosion, transport and deposition of sediments
Major subsystems include:- Atmosphere-Ocean system, River systems- Glacial systems, Groundwater systems- Shoreline systems and Eolian (wind) systems
The Hydrological CycleThe Hydrological Cycle
The Hydrological CycleThe Hydrological Cycle
The Solar SystemThe Solar System
The Solar System Consists of:The sun (center of the solar system) and eight planets
Four inner planets of the solar system are called terrestrial planets: (Mercury, Venus, Earth and Mars)
The Solar SystemThe Solar System
The Solar System Consists of:
>10,000 asteroids (asteroid belt between Mars and Jupiter)
An Asteroid With Impact CratersAn Asteroid With Impact Craters
The Solar SystemThe Solar SystemThe Solar System Consists of:meteorites (pieces of rocks and minerals frozen in
gases)
Hale-Bopp Comet seen (1997) with long glowing tail due to ice vaporization
The Solar SystemThe Solar SystemThe Solar System Consists of:natural satellites or moons (>64 moons)
all the planets formed same time from same general materials and move counterclockwise in an elliptical orbit around the sun
Solar Systems Solar Systems
Pluto is no longer regarded as a planet of the solar system
Solar Systems Solar Systems
Pluto is not part of our solar system because of:
- its unique oblique orbital plane and
- its relatively higher density, given its location
Solar Systems Solar Systems
This is the current composition of the solar system
All planets orbit in the same plane as the sun’s equator
Solar Systems Solar Systems
The Nebula theory is the most accepted explanation of how the solar system is formed
According to the Nebular hypothesis:
- solar system evolved from rotating cloud of dust and gases called nebula
- nebula contained mainly hydrogen and helium produced by the Big Bang
- nebula began to contract at about 5 billion yrs ago
Solar Systems Solar Systems
According to the Nebular hypothesis:
- nebula became flat and disk-shaped with the protosun at the center
- inner planets began to develop from condensed
rocky and metallic clumps with high melting point
- strong solar winds removed the lighter gases like hydrogen and helium from the inner planets
Solar Systems Solar Systems
According to the Nebular hypothesis:
- larger outer planets began to form from the lighter gases with a high percentage of ices or frozen gases – water, carbon dioxide, ammonia, and methane
Glowing nebular clouds of gases and dust particles become concentrated to form stars
Gravitational collapse of nebula causing its inward contraction
Nebula contracted into a rotating disk and heated up as gravitational energy converts into heat energy
Cooling nebula condenses to form tiny rocky and metallic solid particles
Collision of dust-size particles join to form asteroids and accrete to form the planets
Features of Terrestrial PlanetsFeatures of Terrestrial Planets
Terrestrial planets: Mercury, Venus, Earth & Mars
Composed of minerals and rocky materials
more dense (>3gm/cm3)
Less oblate in shape (more nearly spherical)
Slower in rotation and Smaller in size
Diverse and shallow atmosphere
Common Features of The PlanetsCommon Features of The PlanetsPlanets Rotation Time
(Days)
Equatorial Diameter (km)
Mean Density
(g/sq. cm)
TERRESTRIAL PLANETS
Mercury 58.7 4,880 5.43
Venus 243 12,104 5.24
Earth 1 12,760 5.52
Mars 1.03 6,787 3.98
JOVIAN PLANETS
Jupiter 0.41 142,796 1.33
Saturn 0.43 120,660 0.69
Uranus 0.72 51,200 1.27
Neptune 0.67 49,500 1.76OTHER PLANETS
Pluto 6.39 2,300 2.03
Features of Jovian PlanetsFeatures of Jovian Planets
consist of: Jupiter, Saturn, Uranus Neptune
much larger in size
composed entirely of gases and less dense
much more oblate and rotate more rapidly
dense and turbulent atmospheres
Unique Features of Planet EarthUnique Features of Planet Earth
organized into four spheres: (atmosphere, hydrosphere, biosphere and lithosphere)
appropriate temperature for water to exist as solid, gas and liquid
biosphere and hydrosphere unique to earth
Unique Features of Planet EarthUnique Features of Planet Earth
earth’s surface is dynamic (continuously changing) because of:
- movement of materials powered by highinternal heat
- movement of surface water and windspowered by solar energy
atmosphere is 78% nitrogen and 21% oxygen
Earth’s Atmosphere ComparedEarth’s Atmosphere Compared
Earth’s AtmosphereEarth’s AtmosphereIt is the envelope of gases held in place by
gravity
Dominant gases by volume of dry air:- Nitrogen (78%)- Oxygen (21%) (no in earliest atmosphere)- Argon (0.93%)- Carbon Dioxide (0.03%)
(used to be more but reduced due to the formation of limestone in the oceans)- water vapor (0-4%)
It extends up to 6000 miles but 97% of atmospheric gases found within 18 miles
The Planet EarthThe Planet Earth
Earth’s Atmosphere ContinuedEarth’s Atmosphere ContinuedThermal layers of the atmosphere
- Troposphere (0-13 km) (weather belt)- Stratosphere (13-55 km) (ozone layer)- Mesosphere (55-80 km)- Thermosphere (80-210 km)- Exosphere (>210 km)
Most weather phenomena occur in troposphereThe major wind systems of planet earth are:
Lat 0o – lat 30o Trade Wind Belt
Lat 30o – lat 60o Westerly Wind BeltLat 60o – lat 90o Polar Easterly Wind Belt
Thermal Layers of Earth’s AtmosphereThermal Layers of Earth’s Atmosphere
Earth’s HydrosphereEarth’s HydrosphereAll water bodies including:
- ocean water 97%- Ice/glacier 2.15%- Groundwater 0.62%- Saline lakes & inland seas 0.008%- Freshwater (lakes & streams) 0.009%- 71% of earth surface is water
Evolution of life is because of the presence of water
Water moves from ocean-atmosphere-land-ocean to form the hydrological cycle
Sequence of operation of the cycle involves: evaporation-condensation (cloud formation)-precipitation-runoff
Earth’s Hydrosphere ContinuedEarth’s Hydrosphere Continued
Hydrological cycle is powered by solar energyGlacier locks up water on land and breaks the
cycleComponents of the hydrological cycle:
- River systems: collect surface runoff and groundwater, hence stream valleys are the most abundant landform on earth
- Groundwater systems: water moving slowly through pore spaces and capable of dissolves soluble rocks to form caverns in Karst regions of Monroe County in Illinois and Mammoth Cave in Kentucky
Earth’s Hydrosphere continuedEarth’s Hydrosphere continued
- Glacier systems: Pleistocene glacier occurred covered much of North America and Europe with ice sheets about 15,00 years ago.
Antarctica Continental glacier is 2.0-2.5 Km thick and covers 13 million Sq. Km. Today, 2% of earth’s total water is glacier
- Shoreline systems: areas affected by wave action and produce wave-cut cliffs,
terraces, delta, beaches, bars, and lagoons.
- Wind systems:
Earth’s BiosphereEarth’s Biosphere
The world of all plants and animals 1.75 million species already described >13 million species estimated Today’s species represent only 10% of species that
ever lived 15-20% of all species would be extinct by the
beginning of the 21st century Marine organisms form exoskeletons and shells from
seawater They also form fossil fuels and beds of limestone Preserved as fossils and help to reveal earth history
GeosphereGeosphere
The geosphere is the solid earth extending from the surface to the center of the planet (about 6400km)
Its outermost solid layer is called the lithosphere and about 70-100 km thick
It is broken into lithospheric plates made up of seven major plates and about a dozen minor plates
lithospheric plates moved by convection currents
Earth’s Lithospheric PlatesEarth’s Lithospheric Plates
Earth’s Lithospheric PlatesEarth’s Lithospheric Plates
Earth’s MoonEarth’s Moon
No atmosphere, No hydrosphere, No biosphere
Densely cratered highlands called Terrae
Lava plains called Maria (fewer craters) is basalt
Craters formed 4.5 billion years ago but still undeformed
Earth’s MoonEarth’s Moon
Earth’s MoonEarth’s Moon
Lunar geologic history:
- initial period of intense meteorite bombardment
- period of volcanic activity
- later period of light meteorite bombardment
- undeformed by internal forces
- undeformed by wind, water, and glacier
Earth’s MoonEarth’s Moon
Luna Time ScaleLuna Time Scale
Review Questions (Topic 1)Review Questions (Topic 1)
1. What are the basic differences between the disciplines of physical and historical geology?A. Physical geology is the study of fossils and sequences of rock strata; historical geology is the study of how rocks and minerals
were used in the pastB. Historical geology involves the study of rock strata, fossils, and geologic events, utilizing the geologic time scale as a reference; physical geology includes the study of how rocks form and of how erosion shapes the land surfaceC. Physical geology involves the study of rock strata, fossils, and deposition in relation to plate movement in the geologic past; historical geology charts how and where the plates were moving in the pastD. None of the above – physical geology and historical geology
are essentially the same
Review Questions (Topic 1)Review Questions (Topic 1)
2. Compared to the age of Earth accepted as correct today, how did 17 th and 19th century proponents of catastrophism envision the Earth’s age?
A. They believed Earth to be much older than current estimates B. They believe it to be about the same as current estimates, give or take a few million years C. They believed Earth to be much younger than current estimates D. None of the above – they didn’t really address the age of Earth
3. ________ was an important 18th century English geologist and proponent of uniformitarianism. A. Charles Lyell B. Isaac Newton C. James Hutton D. James Ussher
4. The currently accepted age of Earth is ______ years. A. 4.5 thousand B. 6.1 trillion C. 4.5 billion D. 6.4 million
5. The ____ division of the geologic time scale is an era of the phanerozoic eon.
A. Paleocene B. Paleozoic C. Permian C. Proterozoic
Review Questions (Topic 1)Review Questions (Topic 1)
6. The ____ forms the relatively cool, brittle plates of plate tectonics. A. Asthenosphere B. Lithosphere C. Eosphere
D. Astrosphere
7. All of the following are possible steps of scientific investigation except for _____. A. The collection of scientific facts through observation and measurement B. Assumption of conclusions without prior experimentation or observation C. The development of one or more working hypotheses or models to explain facts D. Development of observations and experiments to test the hypothesis
8. The ____ refers to the total of all life on Earth. A. Hydrosphere B. Atmosphere C. biosphere D. asthenosphere
Review Questions (Topic 1)Review Questions (Topic 1)
9. A ____ system is one in which energy moves freely in and out, but no matter enters or leaves the system. A. Closed B. Open C. Feedback D. Equilibrated
10. _______ is often paraphrased as “The present is the key to the past.” A. Biblical prophesy B. Uniformitarianism C. Catastrophism D. Aristotelian logic
11. ______, a popular natural philosophy of the 17th and early 18th centuries, was based on a firm belief in a very short geologic history for Earth. A. Ecospherism B. Exoschism C. Uniformitarianism
D. Catastrophism
12. The ________ proposes that the bodies of our solar system formed at essentially the same time from a rotating cloud of gases and dust. A. Big Bang theory B. Plate tectonics C. Nebula hypothesis
D. Heliocentric theory
Review Questions (Topic 1)Review Questions (Topic 1)
13. The doctrine of uniformitarianism implies that the current forces and processes shaping the earth have been operating for a very long time. A. True B. False
14. The currently accepted age of Earth is approximately 4.5 million years. A. True B. False
15. A scientific theory is a tentative or untested explanation that is proposed to explain scientific observations. A. True B. False
16. In an open system both energy and matter flow into and out of the system. A. True B. False
17. According to the nebular hypothesis, all the bodies in the universe
evolved from a rotating cloud of gases and dust about 5 billion
years agoA. True B. False