(1) Introduction Flashcards

1
Q

What is Geology

A

The scientific study of the earth

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2
Q

4 spheres that make up Earth

A

Geosphere (solid earth), Atmosphere (gaseous), Hydrosphere (water in all 3 forms), Biosphere (life-forms).
The interaction between the spheres is continuing since Earth formed.

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3
Q

Physical Geology

A
  • Major branch of Geology which deals with:
  • Materials that make up the Earth
  • Changes in the surface and interior of Earth
  • Forces that cause those changes
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4
Q

“The Dynamic Earth”

A
  • The earth is constantly changing.
  • Geologic changes occur in an instant (volcano, earthquake), or over millions/billions of years.
    Species come and species go. The only constant for life on earth is change.
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5
Q

Why study Geology

A
  • Direct applications to soils, engineering, chem, physics, and bio.
  • Potential career as geologists.
  • Natural phenomena are interesting.
  • Knowledge about natural geologic hazards.
  • Protecting our environment.
  • Context of ourselves as humans in relation to planet earth.
    Geological materials supply things human society needs.
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6
Q

Geologic Resources: Energy Resources & Mineral Resources

A

Materials of geologic origin that we extract from the earth for our use. ER: petroleum, coal, uranium, geothermal energy, plastics (derived from petroleum). MR: metals (aluminum) and non-metals (salt)

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7
Q

Base Metals vs Precious Metals

A

BM: iron, copper, aluminum, lead, nickel, zinc
PM: gold, silver, platinum

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8
Q

Earth’s Interior

A

Three major concentric zones: Crust, Mantle, and Core

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9
Q

Crust

A
  • Outer layer of rock that forms a thin skin on the earth.
  • Relatively rigid.
  • 2 types: Oceanic: avg 7 km thick, dense; Continental: 10-70 km thick, avg 30-50 km, thickest under mountains, less dense.
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10
Q

Why oceanic crust denser than continental crust?

A
  • Oceanic crust is made of rock that have denser material
  • Oceanic crusts higher in Mg and Fe lower in Si, Na, and K
  • Nothing to do with water in top
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11
Q

Mantle

A
  • Middle zone of the earth.
  • 2900km thick.
  • Inaccessible to direct observation (studied mainly through geophysical methods).
  • Solid rock (but high in T and P = plastic behavior)
  • BUT parts flow slowly
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12
Q

Core

A
  • Innermost zone of earth
  • 3470km thick
  • Consists of inner (solid) and outer (liquid) zones
  • Inaccessible to direct observation
  • Probably consists mainly of iron and nickel (b/c of magnetic field (Ni), density of the earth, and space materials)
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13
Q

Earth is layered with respect to…

A
  • Earth is layered with respect to both compositon and density.
  • The volatiles that make up Earth’s hydrosphere and atmosphere came from volcanic degassing during differentiation.
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14
Q

Earth’s two heat engines

A

External (sun) and Internal (core)

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15
Q

External heat engine

A
  • Circulates atmosphere and oceans
  • Influences surficial (on earth’s surface) process (ex: weathering and erosion)
  • Destructional process (breaks down land masses)
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16
Q

Internal heat engine

A
  • Heat moving from hot interior to cooler earth
  • Convection cells
  • Generates tectonic forces within earth that: cause rock to deform; and cause parts of the crust to move horizontally and vertically
  • Constructional process (build up land masses)
17
Q

Earth gets hotter towards…

A

Earth gets hotter towards its centre

18
Q

Pressure increases…

A

Pressure increases with depth of burial under rock.

19
Q

Where does earth’s internal heat come from?

A
  • Leftover heat from the planet’s formation (vast accumulative of heat during accretion of the planet)
  • Radioactive decay (disintegration of natural radioactive elements)
20
Q

Geologists also subdivide the upper parts of the earth

Lithosphere

A
  • Crust and uppermost mantle
  • Avg 70km thick beneath oceans
  • ‘litho’ - Greek word for ‘rock’
  • Relatively rigid, brittle, and strong
21
Q

Asthenosphere

A
  • Upper part of the mantle under the lithosphere
  • 70 - 200km deep
  • ‘asthenos’ - Greek word for ‘weak’
  • Soft, flows, plastic
  • Lubricates layer over which lithosphere moves
22
Q

Why is the core suspected to be Iron and Nickel?

A

Asteroids are made of iron and nickel and earth was produced in space from space materials