Geology Lab

Contour Interval

On a topographic map, tells the distance in elevation between adjacent contour lines.

Contour Lines

A line on a map joining points of equal height above or below sea level.

Index Contour

On a map, a darker, heavier contour line that is usually every fifth line and that indicates a change in elevation.

Continuous or closed in lines

Contour lines must be. . .

Hills or knob-like elevation

circular contour lines represent. . .

Closed depressions

Hachure markings pointing downslope represent. . .

Steep slopes

Contour lines are closer together on. . .

Gentle slopes

Contour lines are further apart on. . .

Uphill

The “V” point which direction?

Valleys

Contour lines bend uphill or from a v-pattern in. . .

They merge on vertical cliff

Contours do not merge or cross each other unless. . . (Dotted lines)

Water depth or glacier surface

Contour lines shown in blue represent

Maximum relief

The difference in elevation between the highest and lowest points in the area being considered.

A benchmark

A point of elevation that has been surveyed—marked with an ‘x’ or a ‘bm’

Magnetic declination

The angle formed between the direction of true geographic north and the direction of magnetic north.

Factional scale

a ratio expressed is form a fraction. There are 63,360 inches in a mile. Therefore, a scale of one inch to the mile is expressed as the representative fraction 1:63,360, the units must be the same. Any unit of measurement may be used with this scale. Thus, one inch on the map, represents 63,360 inches on the actual surface; one centimeter on the map represents 63,360 centimeters on the surface, etc.

Graphic scale

a line divided into units representing miles or kilometers. The graphic scale is useful in that a map containing a graphic scale can be enlarged or reduced, and the graphic scale will remain valid. This is not true for the fractional scale.

Verbal scale

A scale expressing in words, such as “one inch equals one mile,” meaning one inch on the map equals one mile on the ground.

Longitude

run north and south, but are measured in degrees east and west of the Prime Meridian, which runs from the north pole to the south pole through Greenwich, England. The Prime Meridian is the O degree of longitude.

Latitude

Run east and west, but are measured in degrees north and south of the Equator. The equator is the 0 degree of latitude.

El Niño

conditions prevail when a band of warm surface water extends eastward in the Equatorial Pacific Ocean, to just off the coast of South America. This results in a center of high atmospheric pressure in the Western Pacific and a center of low pressure in the Eastern Pacific

La Niña

The cool surface water counterpart (that is, a band of cool surface water off the coast of South America) is known as

Weather

What happens from day to day and hour to hour: rain or sunshine, cold or heat. It is based on local, daily meteorological conditions.

Climate

The long term (decades and longer) regional meteorological conditions.

Early (youthful) stream development

these rivers are characterized by down-cutting, the water slicing deep, steep-walled canyons into the rocks. Often there are waterfalls and rapids, and the valley walls tend to be "V" -shaped and the stream channel is relatively straight. Clearly, erosion is the primary effect that water is having on the bedrock in the area.

Middle (mature) stream development

the dominate process is lateral, or side-to-side, cutting with some depositional processes, too. This shapes a valley with moderate, sloping walls. The lateral cutting may cause the river to meander a bit, so there is the forming of a narrow floodplain.

Late (old age) stream development

much of the surrounding rock has been removed, and the landscape has undergone a great deal of smoothing and flattening. Gentle, rounded hills may remain with a low river valley and here we begin to see the cumulative effects of deposition with the broad depositional floodplain.

Stream gradient

The slope of the stream bed. It is he decrease in elevation described in feet per mile (feet/mi).

Water table

All pores pace, or void space, in the rock is filled with water. The surface of the water table can, to a slight degree, reflect the topography or surface of the land.

Porosity

Refers to the percentage of pore space in the rock. In order for the water to be transmitted through porous rock, the pores must be interconnected.

Aquifer

If the rock is permeable and contains water it is called an. . .

Tarn

A small lake in a Cirque is called a. . .

Horn

a steep sided, pyramid-shaped peak produced by the head-ward rock plucking of several cirques into a mountaintop. Thus, this plucking creates several very steep walls that rise up to the summit of the peak. Probably the most famous example of a horn is the Matterhorn in the Swiss Alps.

Lateral Moraine

till ridges that mark the side edges of the glacier. A single valley glacier can produce a single terminal moraine, which rounds the front of the glacier and changes as it runs along each side of the glacier into two lateral moraines.

Karst topography

An area that is characterized by caves is referred to as... (Many times solution will cause the 'roof' of a cave to become too 'thin' and collapse, forming a sinkhole. Surface streams may suddenly "disappear" into the underground as they flow into sinkholes.)

Glacial cirque

a bowl-shaped depression on the uppermost, or "upstream" part of the glaciated valley. The shape of a this might be described as semi-circular, crescent-moon shaped, or finger-nail shaped. The outer curve of the "fingernail" is very steep and wall-like, formed as the uppermost part of the glacier, which has frozen to the rock wall, plucks rock as it is torn away under the downward pull of gravity.

Valley trains

bands of glacial sediment that have been transported and sorted by streams that almost constantly flow from the terminus of the glacier as the ice melts. Thus, these deposits of stratified drift are both glacial and fluvial; they are fluvio-glacial. On maps, valley trains are represented as tiny brown dots which are found down slope from the end of the glaciers.

Submergence

The fall of land with respect to sea level is often called. . .

Arete

a sharp, jagged, knife-edged ridge produced between two cirques or two glaciated valleys. The arête is obvious because, when viewed from the side (as in a topographic profile), it would appear as the shared arm of two "U" shapes placed side- by-side. The arête occupies the area that would be called a divide between the glaciated valleys.

Hanging Valley

a "U - shaped" glacial trough in a tributary valley whose "floor", or base, that doesn't match the "floor" of the main glacier valley it connects to. This is caused when the weight of glacial ice flowing in the tributary is drastically less that the weight of the ice flowing in the main valley. This causes a pronounced miss-match of the valley floors after the glacial ice melts.

Paternoster Lake

chains of small lakes in a glaciated valley that are connected to each other by streams. These are often described as appearing like strings of pearls-well, if you imagine that the "pearls" are blue lakes, and the "string" is a series of streams connecting the two. The lakes occupy depressions in the ice-sculpted bedrock.

Terminal Moraine

The most down slope “toe” end of the glacier is called the terminus (corresponding to the “toe” area of your foot), and the till that is left there when a glacier melts is called the. . .