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Unformatted text preview: Understanding Earth
A Dynamic and Evolving Planet In case you missed
Office: Office: Madison Hall, 222B Office Office Hours:
After After class or by appointment . Phone: 258Phone: 258-0544 e-mail: [email protected] Chapter 1 In In case you missed
Course Course information on Moodle .
Changing Earth Textbook
Text Text for this coursecourseMonroe & Wicander Fifth Edition – Course outline and schedule, including dates of exams Bonus Bonus point assignment is up until January 28 If If something goes wrong, contact me! Be Be on time! Turn off cell phones! Get Get scantrons for exams! Register Register ‘clicker’ at www.iclicker.com/registration *also need ‘clicker’ Clicker
also also need ‘clicker’ You You must register your clicker online! http://www.iclicker.com/registration 1 Finding clicker ID number Use Cajuncard number (9 digits) e.g. 123456789 Get this number from the back of the clicker Introduction
dynamic The The Earth is dynamic The The Earth has evolved throughout history and will continue to evolve
– Climate – Position of continents – Life – Coastlines Introduction
system We We study Earth as a system
– Combination of related parts that interact in an organized fashion. Introduction
Earth Earth subsystems
– – – – Atmosphere - gases Hydrosphere - water Biosphere – living or once-living material onceGeosphere
Lithosphere Lithosphere Mantle Mantle Core Core Earth: a dynamic planet 2 …. We are part of it! We are part of it!
Our Our presence affects the system Our Our actions can produce wide-ranging widechanges we are not aware of We We need to understand how the various Earth systems work We We need to understand how our actions affect the balance between systems Introduction
What What is Geology? – The scientific study of the earth
its its origin, its history and dynamics, and the changes the Earth undergoes through time. Includes surface, ocean floor, interior. Geology γεο Geology = γεο λογοσ
– (Greek “geo logos” ) = Earth study Lake Powell, Colorado River What is Geology?
Divisions of Geology:
Physical Geology: Understanding the materials composing the Earth and the processes that operate within and on the surface of Earth What is Geology?
Specialties of Geology : GEOL 105
Historical Geology: Understanding the origin of Earth and its evolution through time. Geochronology Planetary Geology Paleontology Environmental Geology Geochemistry Mineralogy Hydrogeology Geophysics Structural geology Stratigraphy Seismology Oceanography GEOL 106 3 Geology and the Formulation of Theories
Plate Plate Tectonic Theory The The Rock Cycle Organic Organic Evolution Geologic Geologic Time and Uniformitarianism These theories, supported by extensive research, are the cornerstones of the study of geology, and help explain many seemingly unrelated observations. Scientific Method
Accumulate Accumulate observations Make Make one or more hypotheses (possible explanations) Test Test the hypotheses by experiment or additional observations If If one hypothesis is confirmed as the probable explanation it is called a scientific theory Scientific Method Scientific Method
How How do we know the Earth is round? Images Images from space programs! 2000 2000 years ago it was common knowledge that the Earth is flat! Aristotle Aristotle concluded it is not:
– Lunar eclipse – Northern star – Ships approaching port
On the sphere of the world – Johannes de Sacrobosco (1230) Science
Nothing Nothing in science is ever proven. Science is an asymptotic approach to “absolute truth”. Science
Deals Deals with facts (observations). Observations Observations are things we all agree upon. Science Science seeks to explain the natural operation of the facts. very A theory is an explanation that is very theory good and withstands attempts to discredit (disprove) it. 4 How Does Geology Affect our Everyday Lives?
Natural Natural Events Economics Economics and Politics Our Our role as Decision-makers DecisionConsumers Consumers and Citizens Global Geologic and Environmental Issues Facing Humankind
Overpopulation Sustainable Sustainable Development
1999: 6 billion 2020: 7 billion Global warming Temperature change Temperature change in future Tide Gauge, Baltimore, Maryland Significance of shorelines 5 Origin of the Universe
The Big Bang Model
– 15 billion years ago – Hot, dense state followed by expansion, cooling and a less dense state – Evidence includes:
Expanding Expanding universe Background Background radiation = faint afterglow of big bang Origin of the Universe
The Big Bang Model
Universe Universe consisted of energy, not matter Four Four basic forces separated and universe expanded (gravity, electromagnetic force,
strong nuclear force, & weak nuclear force) 300,000 300,000 years later, universe cooled off enough for matter (helium and hydrogen (helium atoms) to form, and photons separated from matter to create light Origin of the Universe
The Big Bang Model
Universe Universe continued expanding & cooling Stars Stars and galaxies formed, and chemical makeup was changed by matter given off as stars die Origin of the Solar System
Solar Nebula Theory
4.6 4.6 billion years ago Condensation Condensation and collapse of interstellar material (gas & dust) in an arm of the Milky Way galaxy Cloud Cloud of material formed a counter-clockwise rotating disk counterMaterial Material concentrated into center of disk and formed the Sun and surrounding solar nebula solar Rotation Rotation within the solar nebula formed localized eddies where material concentrated into planetesimals planetesimals that eventually formed planets. The Differentiation of Early Earth A Dynamic Planet
The The Core
– – – – Solid inner Liquid outer Fe, some Ni Density = 10-13 g/cm3 10- The The Mantle
– Peridotite (Fe, Mg rich) – 3 zones Solid, Solid, homogeneous Fe, Ni melt & sink Layered Earth! Lower Lower mantle – solid Asthenosphere Asthenosphere – flows Upper Upper mantle - solid The The Crust Perhaps the most significant event in Earth history, the ‘settling’ of material according to density resulted in a layered Earth. This concentric arrangement of material led to the formation of continents, oceans and the atmosphere. – Oceanic
Basalt Basalt 3.0 3.0 g/cm3 – Continental
Si Si & Al 2.7 2.7 g/cm3 6 The Earth is an avocado!
core A Dynamic Planet mantle – Crust & upper mantle – Broken into rigid plates – Plates move over asthenosphere – Interactions between these plates form volcanoes, earthquakes, mountain ranges and oceans = PLATE TECTONICS! 7 ...
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This note was uploaded on 05/18/2011 for the course GEOL 105 taught by Professor Jack during the Spring '08 term at University of Louisiana at Lafayette.
- Spring '08