Physical Geology Test 1

Scientific Method

collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions.

other approaches

historical, systems science, invention, discovery

Nebular Hypothesis

the theory that a solar system evolves from a hot gaseous nebula (formed from gas and dust that orbited the sun)

what is a planet?

orbits a star, spherical, has cleared its neighborhood of other objects (terrestrial/gas giant planets)

subdivisions of mantle

Upper & Lower are distinguished by seismic wave velocities (density)

Lithosphere and Asthenosphere

The rigid lithosphere, which includes the crust (brittle), rests on the softer material of the asthenosphere (plasticity).

energy

expressible as motion, light, or heat. almost all comes from sun, small portion is from earth, even smaller is from tides

fossil fuels

composed of molecules that release energy, chemical remnants of organisms that got THEIR energy from the sun (oil, coal, natural gas)

where does earth internal energy come from?

remnant heat, frictional heat, radioactive decay (when things die, they release heat)

atmospheric structure

troposphere, stratosphere, mesosphere, thermosphere, w/ pauses in between

How do Earth's layers help make lfe possible?

core=produces magnetospehere (magnetic shield)

mantle=regulates biochemical cycles

crust=provides surface to exist on

convection in the core

outer core circulates, hot core outwards, cools down, and goes back in

what is a mineral?

a naturally occurring, inorganic solid that has a crystal structure and a consistent chemical composition

minerals are crystals (orderly repetition of atoms)

continental vs oceanic lithosphere:

Continental

-low density

-crust composed of silica rich material 30-60 km thick

-high silica content

Oceanic

-denser

-60 km thick

-top 7 km low silica, basalt composition

Lithosphere

the solid, outer layer of the earth that consists of the crust and the rigid upper part of the mantle

Athenosphere

The soft layer of the mantle on which the tectonic plates move

Wilson Cycle

The cyclical opening and closing of ocean basins caused by movement of the Earth's plates

convergent boundaries

Places where tectonic plates are coming together

subduction zones

places where plates are pushed down into the upper mantle

continental collision

when two continental plates collide pushing the continental crust up to form mountains

divergent boundaries

tectonic plates spreading apart, new crust being formed (ex. mid-ocean ridges, rift valleys).

midocean ridge

an undersea mountain range that forms on either side of a rift

continental rift

A linear belt along which continental lithosphere stretches and pulls apart

transform boundary

A plate boundary where two plates move past each other in opposite directions

phaneritic, aphanitic, porphyritic

phaneritic:

igneous rock texture in which minerals are easily visible without magnification

aphanitic: fine grain, cant be seen

porphyritic: mix of the two

common minerals

plagioclase Feldspar

Orthoclase Feldspar

Quartz

Pyroxene

Amphibole

Muscovite

Biotite