Geology Final !

Streams

Flow along the path of least resistance from head to mouth.

Drainage Basin/Watershed

The land area that collects water to a stream.

Drainage Divide

Imaginary line separating one basin from another, flowing from ridge.

Continental Margin Labeling

Hydrologic Cycle

A summary of the circulation of Earth’s water supply

Watershed Label

Stream Network Label

Dendritic, rectangular, radial, and trellis

Types of Streams

• Perennial- Flows year round

• Intermittent- Flows during part of the year

• Ephemeral- Flows during a storm

• Exotic- Flows in a dry region en route to the sea

Braided Stream

Networks of interweaving channels, low discharge, low sinuosity, and a lot of sediment.

Meandering Stream

Formed when there is a low surface gradient and high sinuosity.

Stream Discharge

Volume of water passing a certain point per unit time.

Width*Height*3rd Dimension

Base Level

Lowest level to which a stream can erode its channel, the elevation at a streams mouth.

Stream Gradient

The slope aka vertical elevation drops over a horizontal distance.

Stream Hydrograph

Plot of discharge versus time.

• Discharge increases during a flood.

• Runoff from steep drainage is fast.

• Runoff from a basin is spread over time.

Stream Discharge

Long term trends and sediment load vary throughout the year.

Downcutting

Forms new lower floodplain, leaving series of terraces.

Headword Erosion

One stream erodes upslope fast and intersects another stream, capturing or diverting the flow.

Dissolved Stream

Chemical matter dissolved in the water.

Suspended Load Stream

Largest amount of material transported by a stream.

Bed Load Stream

Particles moving along the stream bottom by saltation and traction.

Stream Capacity

Maximum load a stream can transport (stream discharge).

Stream Competence

Maximum particle sizes a stream can transport (stream velocity).

Cutbank and Point Bar Label

Oxbow Lake

Formed by meander cutoff.

Cutoffs

Formed when cut banks coverage and meander neck thins.

Levee

Raised embankment built up on either side of a river from flooding, keep flow in channel.

River Terraces

Formed by downcutting the lower floodplain.

Weathering

Physical breakdown and chemical decomposition of rock.

Erosion

Physical removal of material by water, wind, ice, or gravity.

Mass Wasting

Transfer of rock and soil downslope under the influence of gravity.

• Type of rock, geologic structure, climate, chemicals in water, biotic activities, and time.

Exfoliation

Release of overburden from the overlying rocks, layers become detached.

Movement of Grains

1. Saltation- Swept up and suspended

2. Rolling- Roll along the surface

3. Suspension- Skip along the surface

Oxidation

Reactions with O2, iron bearing rocks, and wet climates.

Hydrolysis

Occurs when silicate materials are exposed to water and natural acids.

Dissolution

Minerals are dissolved away, releasing ions.

Types of Chemical Weathering

Oxidation, hydrolysis, and dissolution.

Differential Weathering

Exists as temperature changes, physical weathering in cold areas.

Climate

Weathering is more rapid in warm areas.

Geological Structures

Provide pathways for water to weather and erode rocks.

Soil Thickenss

• As temp increases, weathering increases.

• As precipitation increases, weathering increases.

Soil Horizons

• O- Organic material

• A- Organic material and mineral grains

• E- Leached zone

• B- Clay, iron oxides, and calcite

• C- Weathered bedrock

Rock Falls

Loose rocks detach from steep slope.

Identification

Landslide

Collapse of a slope along a planar rupture surface.

Slump

A slide in which a coherent body of rockslides downward along curved rupture surface.

Creep

Slowly moving forward, hardly perceptible.

Avalanche

Downslope slide of snow and rocks.

Lahar

Mudflow triggered by volcanic activities.

Glaciers

Snow is recrystallized under the weight of overlying snow, forming firn, exceeding 5 meters forms glacial ice.

• Move the fastest from zone of accumulation to ablation.

Firn

When show forms dense mass of grains.

Valley Glacier

Mountain areas, flow down a valley from accumulation center.

Continental Glacier

Exist on a larger scale than valley glaciers.

Zone of accumulation

Net gain of ice.

Zone of ablation

Ice loss by melting, evaporating, and calving along its edge.

Snowline

Lowest topographic limits to sustain a year-round snow cover, boundary between accumulation and ablation.

Milankovitch Hypothesis

Earth’s movement around the sun causes natural fluctuations in the climate.

• Shape of Earth’s orbit, angle of Earth’s axis, and Earth’s axis wobbles.

Glacial Plucking

Loosened bedrock freezes to the bottom of a moving glacier.

Glacial Striations

Forms grooves in the bedrock by abrasion, moving ice and debris against bedrock.

Cirques

Spoon-shaped circular depression scoured by glacier.

Horns

Sharp pointy peak sculpted by several cirques.

Aretes

Sharp ridge formed due to erosion of two adjacent valley glaciers.

Trough

U-shaped by a cross section.

Hanging Valley

Tributary glaciated valley hanging above main glacial valley.

Till

Unstratified sediment dropped by glacial ice mode of grain sizes, deposited directly by the ice.

Moraines

Form along the side of a valley glacier, layers of till left by retreating glacier.

Erratic

Large boulder transported by glacier from very far away.

Drumlins

Reshaped ground moraine into streamlined elongated hills.

Eskers

Small sinuous ridges deposited by the melt water of the under-glacier tunnels.

Kettle Lakes

Scattered around the zone of ablation and glacier margins due to melting of remnant blocks of ice as glacier retreats.