Geology Lab Final

15' Maps Graphic Scale

1" = 1 mile

Three Frequently used methods for designating location are

1) Latitude and Longitude 2) Public Land Survey 3) In reference to propionate features

15' Maps Fractional Scale

1:62,500

Section

36 one mile square parcels of land each with 640 acres

3. Contour line never

Branches or Splits

Total Relief

Difference between the hightest and lowest points on a map

Contor lines widely spaces apart indicate?

Gradual Slope

General Rules For Contor Lines

In order to create uniformity between various map publishers, contor lines must conform to certain guidelies

Public Land Survey Example

Northwest 1/4 of the Southeast 1/4 of section 27 T2S R2W

Public Land Survey

Provides a precise method for identifying the location of land, based on a grid system.

R2W means

Second range west of the prime meridian

T2S means

Second township south of the Baseline

Topography means

Shape of the Land

Close together contor lines represent what?

Steep Slope

Township

The six square mile area descrived as being north or south of the baseline

Quadrangles

Two dimensional representations of the three dimensional surface of Earth

Where is the name of a topographic map usually found

Upper right hand corner

Sycline fold

Youngest bed in the middle Plunges towards limbs

When contour lines cross stream valleys or dry stream channels they form

a V that points upstream

A concentric series of closed contours with hachure marks represents

a closed depression

Hills are represented by

a concentric series of closed contour lines

Graphic Scales

aka Bar Scales. are a series of bars divided in to segments that show the relation between measurements on the map to the actual distance on earth.

Fractional Scales

aka Ratio Scales expresses a distance of one unit on the map, represents some distance of the same unit n the surface of the earth

Contor lines never cross except to show

an overhanging or vertical cliff

footwall block

belown the fault plane

Steep slopes are shown by Gentle slopes are shown by

closely spaced contours; widely spaced contours

Dome

concentric geologic structures with all rock layers dipping outward from a central point oldest exposed rock in the center

Basins

concentric geologic structutes with all rock layers dipping inward with the yougest exposed rocks at the central point

If rock type is homogenous the drainage pattern is

dendri c

Relief

difference in elevation between two points on a map

Topographic maps published by the USGS are contoured in

feet or meters usually referenced to sea level

reverse fault

hanging wall moved up in reference to footwall

normal fault

hanging wall moves down in reference to gravity

hanging wall bock

is always aboutve the fault plane

Contor Lines

line drawn on a toppographic map that connects all that have equal elevation above or below a datum

downstream the valley is said to become more

mature

Sinousity

measure of how winding the course of a stream is

number one is the oldest or younges rock layer

oldest

Anticlene fold

oldest bed in the middle plunges towards nose

Footwall block

on left

hanging wall

on right

Contour lines that occur on opposite sides of a valley or hill always occur in

pairs. Single contour lines do not lay between maximum ridge and minimum valley contour lines

1. Contour lines connect

points of equal elevation

2. Contour lines seperate all points of higher elevation from

points of lower elevation

Ranges

provide the eastern and western edges of the township and are descrived as veing east or west of the principal meridian

streams may radiate from a central point

radial

follow reguarly fractured rock

rectangular

datum

reference plane on the earths surface

Tor report a reversal of slope you must

repeat elevations

dendritic

resembles a tree shape

Townships

six square mile areas

stream gradient

steepness of the slope

what is the most common landform on the earths surface

stream valleys

trellis

streams mostly follow the valleys but can cut through the ridges

A stream valley is

the region directley and indirectly eroded by the stream

Discharge rate

the total volume of water passing a certain point

linear ridges and valleys develop a pattern of

trellis

Cut bank

water velocity and turbulence are greater and the abrasive energy of the water and suspended sediments erodes the stream bank.

Point bar

water velocity is less and allows for sand or gravel to be deposited in the point bar

downcutting

which deepens the channel toward the base level

headward erosin

which extends the head of the vally upslope

lateral erosion

which widens the stream valley

the v-shaped part is reffered to as

youthful