2 - Geologic Timelines and Processes

Question 1

Origins of Earth

Answer 1

• Over 4.6 billion years ago, dust and gas get drawn together due to gravity while orbiting around a young sun
• Dust particles moving at different speeds collide, smash together and grow into larger and larger objects until some are planet size
• Large impacts provide substantial energy and initiates warming event, causing moon to be cast off

Question 2

Formation of crust

Answer 2

As earth grew, the available material to collide diminished

Question 3

Formation of atmosphere

Answer 3

Formed as result of releases of gas, held in place due to gravity

Question 4

Ocean and water formation

Answer 4

Due to condensing and comets –> Life

Question 5

Snowball earth

Answer 5

• Rapid cooling led to snowball earth
• Led to massive extinction (also allowed/forced evolution of new species
• Warming due to volcanoes and presence of greenhouse gasses
• Ongoing change throughout Earth’s history (3 times)

Question 6

Combination of factors that caused cooling

Answer 6

• Reduction in greenhouse gasses because of increases in photosynthesis and the weathering of limestone
• Reduced incoming solar radiation
• Increased snow/ice formed, increasing albedo (reflectance)

Question 7

How long have humans been around in earths’ history

Answer 7

0.04%

Question 8

Different temporal scales (geochronologic units) from smallest to largest

Answer 8

• Eons
• Eras
• Period
• Epoch

Question 9

what are different temporal scales based on

Answer 9

Broadly based on biota

Question 10

Anatomy of Earth

Answer 10

• Crust
• Mantle
• Outer core
• Inner core

Question 11

Crust

Answer 11

Thin outer layer

Question 12

Mantle

Answer 12

• Predominantly solid interior of planet
• 84% of Earth volume

Question 13

Outer core

Answer 13

• Liquid
• Iron and nickel rich
• Creates earths magnetic field

Question 14

Inner core

Answer 14

• Solid
• Predominantly iron

Question 15

Uppermist mantle

Answer 15

Called lithosphere and is comprised of tectonic plates

Question 16

Composition of the earth

Answer 16

• Continental and oceanic crust are different
• Convection in liquid outer core drives tectonic plate movement

Question 17

Types of boundaries

Answer 17

• Divergent (rift valleys, ocean ridges)
• Convergent (subduction and mountain/island building)
• Transform (tension build up and slip)
• Hot spots (from thinner parts in the crust)

Question 18

Geologic activity

Answer 18

• Creates Earth we live on today
• Important for creating a hospitable environment and unique regions of Earth
• Influences snow and ice distribution
• Creates geographic features and unique environments
• Main driver of environmental change over long time periods

Question 19

Types of bias

Answer 19

• Confirmation
• Publishing
• Observation
• Selection
• Recall

Question 20

Confirmation bias

Answer 20

Looking for patterns that support the idea already held

Question 21

Publishing bias

Answer 21

Negative results are harder to get published in peer-review

Question 22

Observation bias

Answer 22

Where participants are aware of being observed and act differently as a result

Question 23

Selection bias

Answer 23

Under or over representation of groups or specific characteristics

Question 24

Recall bias

Answer 24

Interviewees remember and recall events differently