General Geology GEOL-G 100 Exam 4

so late and I am crying

List 3 major problems of river erosion

Loss of valuable soil, boundary disputes, floods

Label and define the stages of the hydrologic cycle

evaporation = liquid water on the surface returns to the atmosphere as water vapor.

condensation = water vapor turns to clouds in the air

precipitation = water falls back to surface rain/snow

Runoff = movement on or beneath the surface

List 4 major characteristics of a youthful river and give 2 specific examples of this type of river in North America.

Steep slopes/banks, high velocity of water, straight channel, and small volume of water (Colorado River and Yellowstone River)

Explain 3 major problems of groundwater usage

cone of depression, sinking of surfaces, saltwater infiltration, and contamination from sewage and landfills

Explain the difference between physical weathering and chemical weathering

Physical = broken down into smaller pieces not changed

Chemical = broken down to a basic substance not original rock/mineral

Briefly describe 2 major reasons that have been given to explain the causes of glacial climates and Ice Age

1. Plate tectonics- ice sheets form on landmasses joined at high latitudes.

2. Changes in the Earth’s orbit shape and tilt angle over time.

Quadrangles

four-sided map of a specific part of the Earth bounded by Latitude and Longitude. Usually shown as a 15 or 7 ½ minute quad.

Graphic Map Scale

uses a line marked off in graduated distances (miles, kilometers, feet). You determine approx. distances on the surface of the Earth by measuring directly on the map.

Fractional Map Scale

Compares map distance with ground distance by proportional numbers expressed as a fraction.

Verbal Map Scale

States in words the ratio of the map scale length to the actual distance on the Earth’s surface.

Interval

difference between one isoline and the next

Isolines

any line that joins points equal value of something (over 100 different kinds)

Steep gradient

lines close together

Gentle gradient

lines far apart

Elevation Contours (Contour Lines)

topographic map isolines

Index contours

bold lines with markings

Intermediate contours

regular lines

Contour Interval (C.I.)

The space or distance between the contour lines

Hachure mark

depressions in a landscape symbolized on topographic maps. The initial mark repeats the elevation from the previous line.

Benchmark (BM)

special points on the map that show exact elevation

Relief

the amount of change in elevation between two points on the map

map gradient

a measure of steepness of a slope on a topographic map. rise/run or relief/distance

Fluvial Erosion

running water in rivers/streams causing erosion of geological structures

hydrologic cycle

recycling of freshwater on earth

evaporation

liquid water on the surface returns to the atmosphere as water vapor

condensation

water vapor in the air changes to clouds

precipitation

water falls back to surface as rain/snow (temperature related)

runoff

movement of water on or beneath the surface. Collecting in lakes, rivers, and seeps underground

River drainage basin

all the land area drained by a river and its tributaries

Base Level

usually sea level. This is when the river stops its downward erosion and begins to widen developing a flat valley

mouth

the point where it empties into another body of water

head (headwaters)

the source of the stream

Discharge

the volume of water flowing past a certain point in a given unit of time

Gaging Station

discharge determined by multiplying the area and the velocity data collected

gradient

the slope of a stream channel (vertical drop over a specified distance)

potholes

circular depressions in the bedrock due to the abrasive action of particles swirling in eddies

Dissolved load

transporting of sediments in the form of a solution

Suspended load

the most common transportation of sediments. creates a muddy appearance in water

Bed load

larger particles slide, roll, or bounce (saltation) causes the shape of the materials at the bottom of a river/stream

Meanders

the curves/bends in a river channel. The outside bank is eroded faster than the inside bank where deposition (alluvium) occurs in the form of a point bar

oxbow lake

forms when a meander loop of a river is cut-off and abandoned

meander scar

dried up oxbow lake

delta

a triangular or fan-shaped deposit at the mouth of a river. (birds foot delta =Mississippi river)

Fan Alluvial

delta on land with coarse sediments (usually found at the base of steep mountain slope.)

Levee

natural elevated banks along the edges of meandering rivers

waterfalls and rapids

extreme drops in the river gradient caused by resistant rock beds acting as a temporary base level

Youthful river

steep slopes and banks, V-shaped valley, high velocity of water, waterfalls/rapids straight channel, small volume of water, few tributaries

Mature river

valley starts to flatten out well-developed tributaries, large volume of water, meandering channel

Old age river

wide flat valley with levees, well developed floodplain, slow velocity of water, largest volume of water, many meander scars and oxbow lakes

Groundwater

water which flows or is stored in rock/soil beneath the surface. Originates from precipitation or seepage from surface water. Amount varies with rainfall, types of rock or soil. More ground water than water on the surface.

Porosity

the amount of space in subsurface rock/soil that can fill with water. Usually sedimentary rocks like limestone and sandstone can hold more water than igneous (granite) or metamorphic rocks.

Permeability

the ability to transmit water through the rock/soil material. Determined by size of pores and how connected they are to each other.

Zone of Aeration

part of the ground that can hold more water

Zone of Saturation

part of the ground (below the water table) that can hold no more water

Water Table

top of the zone of saturation which can vary in height

groundwater aquifers

groundwater moves slowly through a highly permeable rock called an aquifer. It is between 2 permeable rock layers called Aquitards. Water flow can vary a few inches to 50 feet per day

Artesian wells

groundwater forced up naturally by pressure from aquifer to the surface. Nicknamed “fossil water”

Springs

where groundwater naturally comes to the surface. The water table intersects the Earth’s suface.

Wells

The method used by humans to remove groundwater where surface water is limited. Can fluctuate due to wet/dry seasons and the amount of rainfall

Permafrost

Permanently frozen ground ice creating frozen subsoil. No wells or springs. Mainly found in Alaska

Caverns (Caves)

a network of underground passageways or tunnels in permeable rock strata. Usually found in sedimentary rock like limestone

Karst Topography

Areas on the earth which have many cave features. Named for former Yugoslavia

Speleothems

depositional features created when the dissolved limestone is redeposited in the form of stone formations

Travertine

limestone with traces of other elements like iron to produce various colors “Bacon Strips”

Stalactite

pointed deposit forming from the ceiling or roof of the cavern

Soda straw

hollow limestone tubes which represent early stalactite formation

Stalagmite

blunt, rounded deposit forming from the ground or floor of the cavern

Column

when a stalactite and a stalagmite join together and continues to increase in width

Rimstone

cave floor deposit which slows water flow in the cave

Cave pearls

pure calcite deposits in a small spherical shape

Sinks or Sinkholes

surface depressions where the roof of the cave has collapsed. The natural opening to a cave

Geysers

violent eruption of hot groundwater caused by contact with underground volcanic rock. Water is superheated to 300-450 degrees Fahrenheit

Hot Springs/Pools

large pools of hot water that do not erupt like geysers

Largest Aquifer

The Dakota or “High Plains”

Cone of depression

formed when groundwater is withdrawn from a well faster than it can be replenished

Weathering

The gradual breakup of rock mainly from exposure to the atmosphere. A very slow process!

Erosion

The removal of rock/mineral material by moving natural agents

Physical or Mechanical Weathering

The rock/mineral is broken down into smaller pieces not changed

frost wedging

rock expands and breaks apart when water freezes (9%) increase by volume

Exfoliation

peeling off the outer layers of an igneous rock resulting in rounded shape (similar to onion scales) creates domes

Chemical Weathering

Chemicals in the environment react with the rock/mineral to break it down to a basic substance. Not the original rock or mineral

Hydration

the rock/mineral reacts with water causing the minerals in the rock to weather. (feldspar and hornblende in granite react with water making clay)

Oxidation

the rock/mineral reacts with oxygen

Carbonation

the rock/mineral reacts with carbonic acid

Acid Rain

forms from sulfur dioxide plus rainwater

Differential Weathering

masses of rocks/minerals that do not weather uniformly. Creates unique landforms due to unequal weathering

Mass wasting (mass movement)

downslope movement of large masses of loose rock material and soil caused by gravity. Causes deaths, injuries, and property damage.

landslides

sudden movement of rock material down a slope of a mountain. Occurs after heavy rains, spring thaws, and earthquakes

Mudflow (Debris flow)

rapid movement of large masses of mud. very common after heavy rains in deserts and humid mountain areas

Rock fall

Pieces of rock break off a cliff or slope and freefall the base. Occurs during freezing

Talus

rock fragments build up at the base of a cliff as a result of rock falls. the slope usually occurs at an angle of 40 degrees. Very hazardous along roads

Creep

slow invisible downslope movement of soil. Only detected by its effect on surface features

Solifluction

Common in Alaska and Northern Canada active soil layer (thaws in summer) and flows over permafrost (frozen ground)

Calving

large pieces of ice that break off the front of the glacier when it wastes into a sea or lake

glacial drift

all rock material carried by a glacier

till

deposits when the glacial ice melts and drops its load

morains

landforms of till in the form of layers or ridges

outwash

deposits sorted by the action of glacial melt water and streams

Cirque

semicircular basin where the glacier begins in the mountains

Arete

sharp-edged ridge formed when 2 cirques are net to each other