planet earth final

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HMS Challenger

- First true oceanographic cruise
- 713 days at sea, covering 79,274 miles
- It discovered about 4,700 new species of marine life, continental shelves, mid-ocean ridges, deep sea trenches

Glomar challenger (DSDP):

-1968-1985
-First research vessel
-Over 60 miles of core collected
-Found proof of seafloor spreading

JOIDES Resolution (ODP):

-1985-2003
-An international effort to determine changes in climate
-2000 deep sea cores

IODP

-Multiple ships across the globe with different platforms

Deep Ocean Trenches:

Convergent boundaries where lithospheric plates subduct into the mantle. Mostly in the pacific ocean.

Continental shelf:

The extension of the adjacent continent covered by the ocean

Epicontinental sea:

A sea that covers the central areas of a continent

Huge amounts of the US were covered during the \_______

Devonian

Graded shelfs:

Sediments go from coarse to fine (beach to offshore)

In modern shelves, it is nearly all sand because of \_______

Sea-level rise since the last glaciation

Continental slope:

Narrow sloped structure with very little deposition. They are transition areas from continental to oceanic crust.
They have a 4-degree gradient.
In an ocean-free world, they would stand out.

Submarine canyons

Deep cuts downward in the continental slope. Caused by underwater landslides of sediment that happen because of earthquakes (creating turbidity current)

Turbidity currents form a deposit known as a \______, a graded bed

Turbidite

Which earthquake helped us discover why submarine canyons exist?

The grand banks' earthquake

Continental Rise

-The flat area that is after the continental slope. Mainly made of turbidites.
-Can have submarine fans at the base of the slope

Abyssal plane

They are very flat, quiet surfaces that make up the largest part of the ocean

What is the average depth of the abyssal plane?

4km below sea level

Lithogenic sediments

Derived from land

What are the two kinds of lithogenic sediments

1. Terrigenuous: Derived from continents (turbidites)

2. Red clays (pelagic clays): Barren regions with very deep water. Only eolian (wind-born), volcanic, and cosmic sources for mud

Biogenic

derived from organisms
-Things that die on the surface sink to the bottom of the ocean, or are eaten and desecrated out to the bottom of the ocean

Kinds of biogenic sediment

Carbonate: foraminifers, coccolithophorids
Silica: diatoms and radiolarians

Ooze

Sediments made of more than 30% of animal skeleton

Distribution of carbonate sediments is done by three processes:

Dilution, destruction, productivity

Carbonate skeletons aren't abundant in the deep sea because...

They dissolve when they reach the CCD

Hydrogenic

Derived from water

Manganese nodules

Found in all oceans and lakes. They grow slowly (a few cm per million years) by layers being added to the outside.

Deep sea sediment distribution map:

1. Terrigenous: Near continents
2. Carbonate ooze: In the shallower parts of the ocean
3. Silica ooze: Where oceans are cold or nutrient-rich
4. Red clay: Deepest parts of the ocean

Vent faunas

Hydrothermal vents with lots of bacteria that act as the "plants". Bacteria deposites sulfide by breaking down components of vent water. (This is called chemosynthesis)

Resovoir

Any environment where water is stored

Water distribution

Oceans: 96%
Glaciers: 3%
Groundwater: 1%
Rivers and Lakes: 0.1%
Atmosphere: 0.001%
Biosphere: 0.0001%

Freshwater reservoirs:

Glaciers and groundwater

Hydrologic cycle

Moisture rises with the air at the equator and is then carried across land and rained back down to the surface

Run-off:

rainfall that is not absorbed by soil and travels to the ocean

Evaporation:

Water that goes into the atmosphere with help from the sun

Transpiration:

Water that goes from plants to the atmosphere directly

Infiltration:

Water that soaks into the ground

How much water does groundwater supply to the US population?

30%

Properties of groundwater

Groundwater is abundant, available during dry periods, and is widespread (able to flow from humid to dry environments)

Water table

The boundary between the saturated and unsaturated zones of soil

Aquifer

Sediment or rock that water easily flows through

Confining beds:

Sediment/rock that restrict the flow of water

Porosity

The percent of the total column of a rock that consists of pore spaces (can be filled with water)

Permeability

The capacity for transmitting fluids

Sand is \_____ aquifer with \______ permeability

good, high

Clay is a \_______ aquifer with \_________ permeability

Bad, low

Water tables are \____ under hills and \_____ under valleys

High, low

Recharge and discharge

Recharge: Where groundwater is replenished
Discharge: Where the groundwater comes back out of the ground

Darcy's law:

Discharge\= K(Δh/d)A

Discharge\= the volume of water moving in a given time
k\= Hydraulic conductivity (permeability)
Δh/d\= Hydraulic gradient (steepness)

Groundwater moves...

0.03 meters/year to 0.3meters/day

If recharge isn't equal to discharge, the water table will....

Flatten out

Artesian well:

A well in which water rises above the aquifer.

Cone of depression:

A cone-shaped depression in a water table caused by water pumping

Salt-water intrusion

near the coast, over-pumping of groundwater causes saltwater to move into the aquifer

What determines porosity

Size and shape of particles, compactness of the arrangement, clogging of pores, cement

Igneous and metamorphic rocks often have what kind of porosity?

Low

Porosity levels

Soil 55%
Clay 50%
Shale 5%
Sand 10-30%
Gravel 20%
Limestone 25% (cavernous is 100%)

Confined and unconfined aquifers

Confined: Bounded between two confining units
Unconfined: Intersects the surface

Perched water table:

Aquifer occurs above the water table

Dissolution

Groundwater combines with carbon dioxide to form carbonic acid which dissolves limestone

Caves form from...

Acidic water beds dissolving the ground above them.

Also, as caves get bigger, sinkholes form on the surface

Karst topography:

Occurs only when the environment is carbonate. There are many closed, small basins that cause tons of sinkholes to form

Things you find in caves

-Icicle-like cones that hang from the ceiling are called stalactite

-The same cones that stick up from the floor are stalagmites

-If a stalactite and stalagmites connect, they're called columns

Why are streams important?

-They shape our landscape
-They take water from land and run it back into the ocean to prevent flooding

Sheetwash:

A film of water a few millimeters thick that covers a ground surface

Steam:

Channelized flow of any size

-Rain erodes the ground until it forms a channel. It can get bigger with more water.

Stream profile

The head is where the erosion starts, and the mouth is the end where it is deposited back into another body of water

Tributaries

smaller streams and rivers that flow into a main river

Drainage basin:

the land drained by a river system

Drainage divide (watershed)

The area that separates two drainage basins, usually a high surface where water can flow in either direction

The great basin

An example of interior drainage, where rivers don't reach the ocean. This made the great salt lake.

The shape of the longitudinal profile of all streams is a...

Concave upward curve
-They are steeper and the head and flatter at the mouth

The ultimate base level for streams is \______, meaning they cannot erode downward any further

Sea level

Base level:

The lowest elevation a steam bed can reach at a given locality

Discharge

The volume of water moving down a stream or river per unit of time (Q\=VA)

discharge equation

(Q\=VA)

Q\= Discharge
V\= Velocity
A\= Area

Competence:

Maximum size particle a stream can transport
-Equal to velocity squared

Capacity:

Maximum load a stream can transport
-Equal to the water's volume. More water \= higher capacity.

Single channel:

In between a V-shaped channel, or base level streams that are sinuous (wavy).

Braided channels:

A network of small channels separated by temporary islands (bars). These form when there is too much sediment for the streams to carry.

Cut banks:

Eroded bank on the side of a stream (high velocity)

Point bars:

Sand and gravel being deposited on the side of a stream (low velocity)

Meanders will sometimes get so extreme that part of it gets cut off, making an \___________

oxbow lake

Floodplains

Flat topography covered by periodic flooding

Levees

-A broad, low ridge of sediment built along the side of a channel. They are built up after foods occur.
-They help to prevent flooding in the future

Deltas

Sediment deposited where a river flows into a standing body of water

Delta planes and fronts

Delta plane: Area above sea level where the river is depositing things
Delta front: Mostly sand that has been deposited

Prodelta

Arpon of clay and silt beyond the delta front

How is mass moved?

Wind, water, gravity, and ice

Mass wasting

The downward movement of rock and soil under the influence of gravity

The downward force is opposed by a \____________

Resistance force (friction)

What happens when the downslope force exceeds the resistance force?

Slope failure

The angle of repose:

The steepest angle that loose material can maintain without collapsing

Oversteepening:

Removing support of the lower material to make the upper material more unstable

Overloading:

Loading a hill (putting heavy things on top) can cause things to fail

Effects of geology on slopes

The dip of the beds can contribute to slope instability, determining the direction of slides

Effects of water on slopes

-Unsaturated soil can help things stick together using surface tension
-Saturated soil will create slickness, separating grains and making them flow

Falls: Free-fall of material

Material topples freely and is not always in contact with the ground

Types of slides: Mass remains intact

-Rotational slides (AKA slumps, sediment going down a curved surface and ending up piled up at the bottom in broken up pieces. Slow, takes several days)

-Translational slides (coherent block slides down a planar surface)

Types of flows: A viscous flow of material

-Soil creep flows: the very slow movement of soil and sediment downhill

Turbidity currents are an example of a \_____

Flow