Earth Science: Earth’s Structure, Plate Tectonics, Conformity
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Earth’s Structure.
o What are the layers of the Earth
 Crust, mantle, outer core, inner core
 Lithosphere, Asthenosphere, Mesosphere
 What is the Moho
o Why is the core solid (high pressure)
o The core has the highest concentration of metal
Wegner’s Hypothesis
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Continental drift
what evidence to we have for continental drift
o fossils
o ancient climates
o continents match-up
o paleomagnetism
What was it Called
Why was his hypothesis rejected (did not have evidence to support his clam)
Plate tectonics
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The lithosphere is divided into plates (oceanic and continental plates)
What are divergent, convergent, trans form fault boundary’s
What three types of convergent boundaries can be formed
The red sea is a divergent boundary
o What are rift valleys and where do they form
o What causes volcanos
o What is a subduction zone
o Where would you find a deep ocean trench
Sea floor spreading
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How is the Atlantic ocean growing
Paleomagnetism shows the different types of rocks produced over time throughout the process
of sea floor spreading
Thermal convection
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This drives plate tectonics
Hot material rises and cooler material sinks causing a circular pattern which causes the
movement of the plates
Earth’s different principles and laws
James Hutton
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Proposed the principle of uniformitarianism
Physical/chemical/biological laws that work today worked in the past, in the exacts same way
Nicolaus Steno
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Proposed the law of superposition
Young layers on top, older layers on the bottom
What is the law of cross-cutting?
An unconformity is a gap in the fossil record
Fossils
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Fossils are the remains of once living organisms
These are found in sedimentary rock
Trace fossils, foot prints and trails left behind in the rock
To preserve a fossil it needs to be rapidly buried and have hard parts
What is an Index fossil
Radioactivity
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An unstable isotope will break apart
The time it takes for 50% of the nuclei to decay is called a half-life
Radiocarbon is used to date back to 75,000 years
Geologists used carbon-14 and carbon-12
Geologic time
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Covers 4.6 billion years
Largest expanse of time is a eon
In the Paleozoic (ancient life), life was restricted to the seas
What likely contributed to the extinction at the end of the Mesozoic era, asteroid impact
We live in the age of mammals