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57 Cards in this Set
- Front
- Back
Geology
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The science that pursues an understanding of planet Earth.
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Physical geology
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examines the materials composing Earth and seeks to understand the many processes that operate beneath and upon its surface
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Historical geology
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seeks an understanding of the origin of EArth and its development through time
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What are some of the problems and issues addressed by geology?
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Natrual hazards, resources, world population growth, and environmental issues
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Catastrophism
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Earth's features formed through sudden and violent changes
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Who believed in Catastrophism?
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Aristotle - 300 bc
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When did James Ussher believe the Earth was created?
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4004BC
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What did James Hutton write?
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Theory of the Earth in 1780
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What was the main idea of this book?
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Uniformitarianism
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What is Uniformitarianism?
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the processes that operate today have operated in the past
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Who was Lord Kelvin and what did he believe?
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the greatest physicist of his day and siad that the Earth cannot be more than 100 million years old.
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What was his assumption based on?
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a simple convective cooling model
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What did Mark Twain believe?
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that scientific research has shed considerable darkness on teh subject of teh Age of the EArth and if they continue at their present pace, wel'll soon know nothing about it
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What did Sir Charles Lyell write and think?
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Principles of Geology - The present is the key to the past
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What do Uniformitarianist today believe?
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That Earth's geological history can be interpreted through processes we see operating today.
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We can also understnad Earht's present by...
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interpreting its past
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Relative dating
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dates are placed in their proper sequence or order without knowing their age in year
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What are a few important markers of relative time...
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Fossils of pre-existing life -such as fish and amphibians
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The principle of _______is useful for dividing PHanerozoic time
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faunal succession
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What is the magnitude of geologic time?
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millions or billions of years
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Science assumes the natural world is...
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consistent and predictable
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What is one goal of scientists?
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to discover patterns in nature and use the knowledge to make predictions
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How do scientist collect data?
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Through observation and measurements
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How or why things happen is explained by using what?
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The scientific method
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Hypothesis
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a tentative or untested explanation
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Theory
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a well-tested and widely accepted view that the scientific community agrees best explains certain observable facts
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Scientific Laws
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porvide brief - usually mathmatical - statements to describe nature
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Are scientific laws superior to theories?
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no
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What does the scientific method involve?
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Gathering facts through observations
Formulation of hypotheses, theories, and laws |
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What are Earth's four spheres?
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HYdrosphere, Atmosphere, Biosphere and Solid earth
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What does Earth's system science aim to study?
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Earth as a system composed of numerous interacting parts or subsystems
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What type of feedback mechanisms do systems have?
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negative and positive
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The hydrologic cycle is one of Earth's _____?
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subsystems
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The Earth's system is powered by ______?
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Solar energy
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What does Solar engery drive?
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most of the external processes in the Atmosphere, hydrosphere and at the earth's surface
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What drives the processes in the Earth's interior?
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Radioactive decay of isotopes U 234, U 235, K 40 etc
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What is the earth's interior comprised of?
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Lithosphere, Asthenosphere, Mesosphere, and Core?
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Concerning the origin of planet Earth what do most researchers blieve about when Earth and the planets formed?
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They believe they all formed at essentially the same time.
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What is the solar nebula?
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A rotating cloud composed of hydrogen and helium
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When did it begin to contract?
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about 5 billion years ago
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What is the Nebular hypothesis?
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Assumes that a flat, disk shape cloud (nebula) with the protosun in the middle began to form inner planets and outer planets
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What were the inner planets formed from?
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metallic and rocky substances
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What were the larger planets formed from?
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fragments of ices - h2o co2 and others
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what are Chondrites?
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contain spherical aggregates of high-temperature minerals condensed from the solar nebula mixed with some pre-solar grains
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What aggregates of high-temperature minerals do Chondrites contain?
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olivine and pyroxene ---called chondrules
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What pre-solar grains are in Chondrites?
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Fe-Ni Meteorites, Lunar samples, Martian meteorites
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Chondrites generally give radiometric ages of ______?
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~4.5 Ga (billion years)
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Regarding the formation of Earth's layered structure what happened with the metals?
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They sank to the center - esp Fe and Ni
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What happened to the molten rock?
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it rose to produce a primitive crust
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What does the chemical segregation in Earth establish?
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Three basic divisions of Earth's interior
-core -mantle -crust |
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What did the primitive atmosphere evolve from?
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gases in the Earth's interior
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What are the Geophysical Divisons of the Earth?
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-Lithosphere
-Asthenosphere -Mesophere -Outer Core -Inner Core |
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Layers defined by composition...
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-Crust
-Mantle -Core |
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Layers defined by physical properties...
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-Lithosphere
-Astehnosphere -Mesosphere -Inner and outer core |
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Have we ever sampled the mantle directly?
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No
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Where have we been able toe xamine slivers of the uppermost mantle and overlying oceanic crust?
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Cyprus, Turkey
Newfoundland Oman |
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Where can you find an oceanic crust section?
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Antakya. Turkey
The Syrian Antioch |