Earth Science Exam 3

Just a heads up! Terms with an asterisk (*) were terms where I was unable to find his definition in the notes, so I found one online.

What are the two types of weathering?

Mechanical and Chemical

What does Chemical weathering do to minerals and rocks?

Decomposes rocks and breaks minerals within rocks down into their chemical components

What does Mechanical weathering do to minerals and rocks?

Disintegrates rocks into smaller pieces

What is mass wasting?

The movement of materials down a slope due to the pull of gravity

How does mass wasting change the landscape?

Gradually wears rocks and landscapes away

Falls

Movement of individual pieces (sand & grains)

Slides

Movement of large amounts of material as a unified mass

Flows

Movement of large amounts of material as a fluid or chaotic mass

*What is erosion?

The process where rocks are broken down by natural forces such as wind or water

What can affect a river’s velocity?

The slope of the land, discharge, debris, and shape

How does the slope of the land affect a river’s velocity?

Discharge

How much water is in a river channel (the more water, the faster the flow)

Rapids

Debris in the river channel

Shape

Water slows down in narrow or shallow channels

What is the base level?

The elevation of the ocean, lake, reservoir, etc that a river flows into

If a river’s base level is lowered, the river’s velocity will?

Increase and erode the channel deeper

If a river’s base level is raised, the river’s velocity will?

Decrease and deposit sediment in its channel

What are Deltas? (Type of river sediment)

Sand, silt, and mud that form at the mouth of rivers

What are Alluvial Fans? (Type of river sediment):

Similar to deltas but forming on dry land

What are Levees? (Type of river sediment)

Accumulation of sand + gravel that form along the banks of a river

What is a flash flood?

A rapid flooding of low-lying rivers.

• Move very large materials

• Water tends to stay with the river’s channel

What are the methods of flood control?

Dams, levees, and flood walls

The Water Table

The top of groundwater generally follows the land surface

Porosity

Rocks must have open spaces (pores) to store groundwater

Permeability

Rocks must act like sponges, allowing water to pass through

Aquifers

Materials with high porosity and high permeability that let water pass through easily

Aquitards

Materials with low permeability that slow or block water flow

What matierals are Aquifers?

Sand, gravel, and sedimentary rocks

What materials are Aquitards?

Clay, shale, most igneous and metaphoric rocks

What types of rock do caves form in?

Limestone, calcite, halite, and gypsum

Hot springs

Occurs if groundwater is heated by nearby magma

Geysers

Occurs if hot groundwater is trapped and becomes super-heated

What is a Wetland?

Areas that may be covered by water all year or less than a few weeks

Why are Wetlands Important?

1. Water purification

2. Flood control

3. Habitat

4. Recreation

5. Ecotourism

Bogs

Acidic water (pH < 7) and receives much of its water from rainfall

Fens

Alkaline (pH > 7) and receives much of its water from groundwater that has filtered through limestone

Marshes

An open, shallow wetland dominated by grasses and weeds with low biodiversity

Swamps

A wetland with deeper water, dominated by trees and shrubs

Bayous

A wetland-like area that develops along slow-moving creeks in areas with flat, low-lying terrain

Constructed wetlands

Designed for the containment and filtration of stormwater or sewage

What percentage of the Earth’s surface is covered by ocean water?

71%

Which hemisphere is covered with more water than the other?

The southern hemisphere is more covered than the north

The Pacific Ocean

• The largest, deepest, and most geologically active ocean.

• It is growing smaller due to plate tectonics

What plate boundaries are the Pacific Ocean influenced by?

Convergent boundaries

The Atlantic Ocean

• Second largest ocean

• Fairly shallow

• Limited geologic activity

• Growing larger

What plate boundaries are the Atlantic Ocean influenced by?

Divergent plate boundaries

The Indian Ocean

• Third largest ocean

• Fairly deep

• Geologic activity mainly on its eastern side near Indonesia

The Arctic Ocean

• Smallest ocean

• Very little earthquake or volcanic activity

Seawater generally contains about ______% of salt

3.5%—-> 35%

Rise

Deepest part of the continental margin, oceanic crust covered in thick sediment

Continental Slope

Edges of continents are located here (Continental plates meet ocean plates here)

Continental Shelf

Shallowest part of the margin, submerged continental crust

Trenches

• Deepest part of the ocean floor

• Pacific Ocean has the most and deepest

What do trenches mark?

Locations of ocean-ocean and ocean-continent convergent plate boundaries

Abyssal Plains

Flat and occur in areas far from plate tectonic activity

Seamounts

• Oceanic volcanoes

• Form at hot spots and divergent plate boundaries (but later pulled away by plate motions)

Mid-Ocean Ridges (MOR)

Divergent plate boundaries and the mountains + structures created by them

Areas without plate tectonic activity are called?

Passive margins and have a shelf, slope & rise

What ocean is a passive margin?

The Atlantic Ocean

Areas with convergent plate boundaries are called?

Active margins, they have a shelf and slope, but no rise.

What ocean is an active margin?

The Pacific Ocean