Geology Exam 4

The time water stays in a reservoir; varies among reservoirs (ex. shallow groudwater- 100 to 200 years; 10,000-20,000 years)

Waves caused by wind, Tides caused by gravity

Equatorial areas and restricted embayments of arid regions

Periodic rise and fall of large bodies of water due to gravitational interactions between moon, earth, and sun

Chemical compounds from land (weathering), chemical compounds from ocean (ex. deep sea vents), ions from volcanic eruptions (ex. sulfate)

Results in a global-scale conveyer belt that circulates water and controls climate
Because of this, the ocean mixes entirely in a 1,500 year period

Salinity is how much disssolved solids (ions) are in the water. ~3.5% or 35 ppt

1. Uplifted rocky coasts dominate
2. Broad, low-lying coastal plains typical; less siesmic activity

71%

More than 97%

4 km

Dunes (w/ or w/o vegetation), vegetation (ex. mangroves, and sea grass), and coral reefs

1. Coral reefs, sandy, rocky, coastal wetlands
2. Waves, tides, currents, humans

Higher salinity and colder temperature. Water sinks. Ex. N. Atlantic cold deep current.

Low glacial flow and high temperatures

Ice (ex. ice caps, glaciars), shallow and deep groundwater, oceans and inland seas, freshwater bodies (rivers, streams, lakes), snow, living things, atmospheric water vapor

The character and shape of the land surface in a region

The individual shapes (valleys, cliffs, beaches, etc.) that make up landscapes.

-Shaped by ancient meteorite impacts and volcanic eruptions
-No plate tectonics, No new mountains or volcanoes, No hydrologic cycle, No erosion from rivers, wind, or ice

Detailed digital data sets of elevation variations produced by radar imaging

The elevation difference between two points separated by a specific horizontal distance.

The variation in land surface elevation

-Agricultural development is often reliant on the nutrient-rich soils created by the accumulation of eroded earth
-Helped feed water sources with essential nutrients, helping the local aquatic ecosystem.
-Shape the land

97% Saline, 3% Freshwater

Sediment that has been deposited by running water (rivers and streams)

A trough dug into the ground surface by flowing water

The main branch of the stream

The smaller branches that feed the main branch

Evapotranspiration, Precipitation, Runoff (sheetflow), Throughflow from soil moisture, Groundwater

Levee

Fjord

1. Sheet flow erodes substrate and creates rills
2. A new channel starts to form and carves into the substrate
3. Eventually, flow is concentrated in a single channel.
4. Tributaries develop and drainage network forms

1. a trickle of water, a very small stream; ephemeral
2. a small watercourse with steep sides, usually cut into soil

-Downcutting and erosive power of surface flow (extends downstream)
-Groundwater sapping

-Rectangular drainage: A highly fractured and jointed surface will result in streams that meet at high angles.
-Not common in nature

Dendritic
-Most common !
-Uniform substrate and uniform initial slope

Radial

Trellis

Parallel

Straight
-Rare in nature
-Upper course (headwaters)

underground cavity formed by dissolution by groundwater (contain speleothems)
-form when calcium carbonate degasses from dripping or flowing water in a cave

1. Landscape dominated by features formed from limestone dissolution by freshwater (often groundwater including caves and sinkholes)
2. They provide porous groundwater aquifers

Braided
-Middle course; Gravel and sand bars; “Braids” of sediment
-Needs high sediment load and high - medium gradient

Meandering
-Lower course; Most common type of river channel
-Needs high sediment load and low gradient

Bedrock and structures and sediment load
Slope changes downstream too

Cut bank: erosion
Point bar: deposition

–Dissolved load – ions in solution from weathering
–Suspended load – fine particles (make water look ‘muddy’)
–Bed load - Moves during high velocity events along the bottom of the stream
------Sandy Portion – Saltation (bouncing)
------Cobbles – Traction (rolling)

Conversion of Potential energy (elevation) to Kinetic Energy (motion). Most energy lost to friction, but 2-4% of total potential energy converted to work of erosion and transportation of sediments

High velocity: sediments are eroded
Low velocity: sediments are deposited

1. water flowing all year, common where there is abundant rainfall, groundwater discharge, and low rates of evaporation
2. do not flow all year common in places with low annual rainfall, a low water table, and high rates of evaporation

1. Porosity-ability to hold water (total volume of open pore space in the rock); Small open spaces
-Porosity can be filled with water or air; Pores can become filled with mineral cement and other fluids, like oil or natural gas.
2. Permeability- Measure of interconnectedness of the pore spaces (ie. connected pores)=ease of water flow
-Ability of fluids to pass through pores; Depends on “connectivity” -> Well-connected = high permeability

1. The water table is the top of the groundwater reservoir.
2. The water table rises and falls seasonally with variation in rainfall and infiltration
3. unsaturated (vadose) zone above the water table = air and water in pores
4. saturated (phreatic) zone below the water table “aquifer” = water fills pores
5. The water table mimics surface topography: Water flows from higher elevations to lower elevations underground

1. sediments or rocks that transmit water easily (ex. Limestone, lightly cemented sanstone)
2. (confining bed) – sediment or rock that does not transmit water easily (ex. Granite, schist)

1. lies at the surfac; in contact with human activities, it is easily contaminated.
2. lies beneath an aquitard; isolated from the surface, it is less susceptible to pollution.

sand, coarse grained sediments, fractured bedrock, caves/karst

Pumping from a well in a water table aquifer lowers the water table near the well
-Pumping groundwater affects the water table. If groundwater is extracted faster than it can be replaced, a cone of depression develops around the well.

High latitudes (polar regions)
• Continental glaciers:
• Ice caps / ice sheets
High altitudes
• Mountain Glaciers (Alpine glaciers)
-Cirque glaciers, Valley glaciers, Piedmont Glaciers

Low temperatures, Sufficient snow fall to accumulate large amounts, gentle enough slope (glaciers do flow)

1. Dry-Based Glaciers- so cold that there is no liquid water present-> move by internal plastic deformation of ice
2. Wet-Based Glaciers- move by basal sliding of the ice over a film of meltwater or water-saturated sediment

Yes, such as jagged mountain tops caused by glaciers, and chnage in valley shapes
1.Before glaciation, valleys are V-shaped, and tributary mouths are the same elevation as the trunk streams
2. During glaciation, the valleys fill with ice and are aggressively eroded and steepen dramatically
3. After glaciation, the landscape is transformed, containing U-shaped valleys, hanging valleys, cirques, arêtes, horns, and other evidence of the erosive power of glaciers.

A layer of snow can be compacted like a sediment, the preexisting ice recrystalizes in a solid state

1. Zone of accumulation- Top of glacier (glacier is growing)
2. Zone of ablation- where glacier can recede (lower on the glacier, but before the terminus/toe
3. Equilibrium- Between the two zones

-Sublimation (ice evaporates into the air)
– Melting (ice melts into liquid)
– Calving (ice breaks off at the toe)

brittle upper layer of a glacier-cracks (can be very big)

Glaciers can accumulate and move sediments
Material transported to the toe (bottom/end of a glacier) piles up as an end moraine->material is called glacial till
Can contain variety of rocks/sediments, poorly sorted, un-stratified, and any size/shape