Presentation on theme: "Introduction to Earth Science/Geology C. Ophardt"— Presentation transcript:
1 Introduction to Earth Science/Geology C. Ophardt Geology, What is it?Geology is the study of the Earth.Includes surface process which have shaped the earth's surfaceStudy of the ocean floorsInterior of the Earth.History of the Earth as it has evolved to its present condition.The Earth has changed throughout its history, and will continue to change (Unifying Theme)
2 Earth Science/Geology - Time Scale Time scale (Unifying Theme)Earth is about 4.6 billion years oldHuman beings - maybe 2 million years.Humans have witnessed only 0.043% of Earth historyHow can we think about changes on earth on a scale of billions of years?
3 Earth Science/Geology - Time Scale II Try to imagine 1 million yearsThat's 50,000 times longer than you have lived.A river deposits about 1 mm of sediment (mud) each year.How thick is the mud after 100 years? -- 10 cm hardly noticeable over your lifetime.What if the river keeps depositing 1 mm/yr for 10 million years? Answer 10,000 meters (6.2 miles).
4 Scientific Method - Inquiry in Earth Science Strongly tied to experiment and observation.Observations can be cast as experiments -- thought experiments.Observation: Wind River Mountains in Wyoming - 10,000 feet above sea level -observe a rock containing many seashells.How did it get there?
5 Scientific Method - Inquiry in Earth Science Questions:Was area covered by an ocean at some time in the past?Was this ocean 10,000 feet deep?Was this area at one time at sea level and unknown forces elevated it to its present elevation?Tie in to previous slide about rate of deposition.
6 Inquiry in Earth Science III Hypothesis:The observation leads to several hypothesesAttempt to explain the observation.Formulation of a tentative explanation is not sufficientWhat additional information may be needed in order to "prove" the hypothesis?New information may modify the original explanation or cause it to be discarded.
7 Inquiry in Earth Science IV Theory: Principle of Uniformitarianism - Slow ChangesProcesses that are operating at present are the same processes that have operated in the past.“Present is the key to the past.”Look at processes that occur today, Infer that the same processes operated in the past.Key Assumption - Laws of nature have not changed through time.
8 Inquiry in Earth Science IV Theory: Principle of Catastrophism: - Fast ChangesMajor changes in Earth’s crustal layers result from catastrophic eventsFloodsMassive VolcanismMassive EarthquakesChanges were sporadicKey Assumption - Laws of nature are the same but the rate of change is not
9 Earth Materials and Processes Slow processesFormation of rocksChemical breakdown of rock to form soil (weathering)Chemical cementation of sand grains together to form rock (diagenesis)Recrystallization to rock to form a different rock (metamorphism)Build mountain ranges (tectonism)Erosion of mountain ranges
10 Earth Materials and Processes Fast ProcessesBeach erosion during a storm.Construction of a volcanic coneLandslides (avalanches)Dust StormsMudflowsEarthquakes
11 Structure of the Earth Crust - variable thickness and composition Continental km thickOceanic km thickMantle km thick, made up of a rock called peridotiteCore km radius, made up of Iron (Fe) and small amount of Nickel (Ni)
13 Structure of the Earth- Hydrosphere Water sphere includes all the earth's water found in streams, lakes, the soil, groundwater, and in the air.Water of hydrosphere is distributed: oceans, lakes, streams.Water is found in vapor, liquid and solid states in the atmosphere.Biosphere - interface between the spheres water moves between hydrosphere, lithosphere and atmosphere by plant transpiration.
15 AtmosphereAtmosphere is a dynamic mixture of gases that envelop the Earth.Two gases, nitrogen and oxygen make up most of the atmosphere by volume.Minor gases include have a significant impact on heat budget and the moisture across the Earth. Water vapor, Carbon dioxideAtmosphere has a layered structure as defined by vertical temperature changes.
16 Structure of the EarthLithosphereOuter rigid part of earth includes the crust and upper part of the mantle.Act as a unit and respond similarly to mechanical deformation.60 miles in thickness to 150 miles thick beneath continents.
17 Structure of the Earth Asthenosphere Lies beneath the lithosphere Extends to a depth of about 400 miles.A small amount of liquid (from partial melting of the upper mantle) in upper 100 milesDetached from the underlying asthenosphere.Capable of flowing - convective.
18 Structure of the EarthMesosphere - about 2500 km thick, solid rock, but still capable of flowing. Another name is Mantle.Outer Core km thick, Fe and Ni, liquidInner core km radius, Fe and Ni, solidAll of the above is known from the way seismic (earthquake waves) pass through the Earth
19 Quiz Questions Ques. 1: The earth formed: A. 455 million years ago. B billion years agoC. 4,550 million years agoD billion years ago Ques. 2: Catastrophism could be use to explain:A. the formation of Grand Canyon.B. the evolution of the coastal area near Siccar Point, ScotlandC. the presence of blue algae in stromatolites.D. the iridium-rich layer observed around the world at the K/T boundary.
20 Quiz Questions Ques. 3: The mesosphere is located between: A. the solid inner core and the liquid outer coreB. the liquid outer core and the asthenosphereC. the lithosphere and the asthenosphereD. the crust and the asthenosphere Ques. 4: To a close approximation, the term that best describes the Earth system is:A. an open systemB. a closed systemC. an isolated systemD. an insulated system
21 Quiz QuestionsQues. 5: The lithosphere is best described as: A. a stiff and rocky layer within the Moho region.B. a rigid layer found upward from the asthenosphere.C. a rigid layer found downward from the asthenosphere.D. a rigid and rocky layer capable of flowing Ques. 6: What are the Earth's "four spheres"? How do they interact? Ques. 7: What is the difference between catastrophism and gradualism or uniformitarianism? Can you cite an example of each?
22 Quiz QuestionsQues. 8: What are the key physical properties of the inner core, outer core, mesosphere, asthenosphere, and lithosphere?