Lectures 2-4

Question 1

The three main tock types

Answer 1

Igneous, Sedimentary, and Metamorphic

Question 2

Law of Original Horizontality?

Answer 2

Sedimentary layers are deposited horizontally and continuously

Question 3

Law of Superposition?

Answer 3

Each layer of sediment is older than the layer above it and younger than the layer below it

Question 4

Law of Cross-cutting Relationships?

Answer 4

If a fault or other body of rock cuts through another body of rock then it must be younger in age than the rock through which it cuts

Question 5

Law of Inclusions?

Answer 5

Clasts in a rock are older than the rock itself

Question 6

Crust

Answer 6

The outermost layer, on top of the mantle

Question 7

Mantle

Answer 7

It has upper and lower sections and includes the asthenosphere, iron, and magnesium-rich silicate minerals

Question 8

Core

Answer 8

Mostly iron metal (very dense), solid inner core, liquid outer core

Question 9

Asthenosphere

Answer 9

The top part of the upper mantle where it is plastic, and partly molten

Question 10

Lithosphere

Answer 10

includes the rigid part of the mantle and the overlying crust, rides on the plastic asthenosphere

Question 11

The three ways we know what the interior of the Earth looks like

Answer 11

Density, Seismic data, Meteorites

Question 12

Main geologic processes active on Earth today

Answer 12

Tectonics, volcanic activity, mass wasting, water, wind, ice -> erosion and deposition of sediment, impact crater, life

Question 13

Fusion

Answer 13

The combination of two or more nuclei to form a different, heavier, element; the by-product is radiation

Question 14

Supernova

Answer 14

The cataclysmic explosion of a star, as a result of internal nuclear reactions

Question 15

Nebula

Answer 15

Dust in space with a density of 1,000 gas molecules/10cm^3

Question 16

Gravitational Collapse

Answer 16

When molecules are concentrated, attracted to each other; may be triggered by a nearby supernova

Question 17

T Tauri Star

Answer 17

Stars that are similar to the Sun, but only about 1 million years old

Question 18

Proplyds (Protoplanetary disk)

Answer 18

Disks of dust and gas around young stars, places where planets are possibly forming

Question 19

Refractory

Answer 19

Materials that condense at very high temperatures

Question 20

Volatile

Answer 20

Materials that condense at very low temperatures

Question 21

Meteorite

Answer 21

An extra terrestrial rock that has fallen through our atmosphere

Question 22

The two main sources of information for how the solar system formed

Answer 22

Astronomical observations and meteorite studies

Question 23

Planetesimal

Answer 23

Small solid bodies, ~100km across, that formed from grain-to-grain accretion of dust

Question 24

Accretion

Answer 24

Solids come together to form larger objects through gravitational attraction and collisions

Question 25

Differentiation

Answer 25

The separation of materials in a planetary body according to density and chemical affinity

Question 26

Conduction

Answer 26

The vibrational energy of an atom is transferred to adjacent atoms

Question 27

Convection

Answer 27

Warm material expands and moves upwards, displacing cooler, denser materials downwards

Question 28

Radiation

Answer 28

The emission of electromagnetic waves from a hot body’s surface to its surroundings

Question 29

Law of Cross-cutting Relationships for impact cratering

Answer 29

If an impact crater, fault, or body of rock cuts through another body of rock then it must be younger than the rock through which it cuts

Question 30

Three things that must be explained by any model for how the solar system was formed

Answer 30

• The planets orbit in the same plane
• They orbit the Sun in the same direction
• The Solar System is zoned from rocky inner planets to gas-rich outer planets to ice-rich comets

Question 31

What Earth most likely looked like 3.8 Ga ago

Answer 31

Most of the surface is covered in an iron-rich ocean, a carbon dioxide-rich atmosphere, and surface temperature over 75 degrees