brooklyn college geology department

BROOKLYN COLLEGE GEOLOGY DEPARTMENT

Exam 1 CC3.32 Online • Exam 1 October 21, 6:05-7:45 rm 3127N

• The PowerPoint is to help you focus on what will be on the exam.

• The exam will consist of 45 questions (multiple choice and T/F) and 6 extra credit questions.

• You are responsible to bring with you: pencil, calculator, string and ruler *Cell phones cannot be used during exam including as a calculator *

Office Hour Update!!

10/13/09 Tuesday 3-5p w/Michelle rm.3114N (appt is necessary!!)

10/14/09 Wednesday 4-6 w/George rm.3114N (appt is necessary!!)

10/21/09 Wednesday 3:30-5:30 George/Michelle rm.3127N (no appt necessary)

Next assignment ‘Fourth Dimension II’ is due via email by 11/18/09


Review for Exam 1 Online Geology Core CC3.32

►KNOW THE DEFINITION OF A MINERAL AND A ROCK

A MINERAL is a naturally occurring, inorganic solid, with a characteristic chemical composition, a highly ordered atomic structure and specific physical properties.

A ROCK, by comparison, is an aggregate of minerals (and other debris such bones or shells) and need not have a specific chemical composition.

http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/mineral_def.html


Review for Exam 1Mineral Properties

►Know the difference between Cleavage and Fracture

Cleavage and Fracture are mineral properties that describe the way a mineral breaks when stressed.

Cleavage describes the way a mineral breaks along its plane of weakness.

Fracture: A mineral property where the atomic bonding between atoms in the crystal structure is perfect with no weakness. When these minerals are stressed they shatter making no two pieces truly the same.

http://academic.brooklyn.cuny.edu/geology/leveson/core/graphics/cleavage/cleave_def.html



Hardness is a measure of a mineral's resistant to abrasion. This property is easily determined and is used widely for field

identification of minerals.

►Know the difference between MOH’S hardness scale and the “simple” STEEL NAIL-FINGERNAIL scale.

http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/hardness_def.html



►KNOW HOW TO CALCULATE THE DENSITY OF A MINERAL.

Density or specific gravity is the ratio of the weight of a substance to the weight of an equal volume of water.

Density = Weight/Volume

1) Begin by recording the weight of the specimen, in this case 155.8 grams.



►HOW TO CALCULATE THE DENSITY OF A MINERAL. Density or specific gravity

2) The amount of water displaced is 20ml = 20cc (920-900)

3) Divide 155.8g/20cc = 7.79 g/cc. So, the density of the minerals is 7.79g/cc.



►KNOW WHAT IS STREAK.

The streak of a mineral is the color it displays in finely powdered form. The streak maybe completely different from the color of the hand specimen. One of the simplest ways of determining the streak of a mineral is to rub a specimen across a piece of unglazed porcelain known as a streak plate.



►KNOW HOW TO APPLY THESE PROPERTIES◄

HARDNESS

DENSITY

STREAK

COLORYou’ll be ask to identify an unknown mineral using these properties which

will be given to you in the test.

Link to mineral ID charts and self-checking table:

http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/resourceMenu_min.html


Review for Exam 1Maps

You will be responsible to answer similar questions as you had on your map assignment. This includes:

Finding the gradientLabeling contoursDetermining stream direction

http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/contourmaps_menu.html


Review for Exam 1

Maps: Determine Direction of Stream Flow

Scale bar length = 100 miles Contour Interval = 50 feet

Elevation of point Q = 583 feet Start Point: Q End Point: R

In what general direction is the stream flowing? Answer: From West to East(The legs of the letter V give you the direction of flow)

Protractor used to determine azimuth readings


Review for Exam 1

Maps: Distance Between Two Points



1) We measure the scale with the ruler and now we know that1.5 cm = 100 miles

Protractor

What is the straight line distance between points Q and T in miles?


Review for Exam 1

Maps: Distance Between Two Points



2) We measure the distance between the two points that is 8.5 cm = x miles

Protractor

What is the straight line distance between points Q and T in miles?


Review for Exam 1

Maps: Distance Between 2 Points

Calculations


Review for Exam 1

Maps: Distance Between 2 Points (MILES)

Scale bar length = 100 miles

Contour Interval = 50 feet Elevation of point Q = 583 feet

Start Point: Q End Point: R

Protractor

Answer:The distance between points Q and T is 567 miles.


Review for Exam 1

Maps: Gradient of a Steam

Scale bar length = 100 miles

Contour Interval = 50 feet Elevation of point Q = 583 feet


Protractor

What is the average gradient of the stream between points R and T? Begin by measuring the length of the stream. Lay carefully a string along the course of the river.


Review for Exam 1


2) Measure the string with a ruler, in this case the measurement is 5 4/16 or 5 ¼ inches.

After completing the calculations (on the left) the distance measured by the ruler is 884 miles (this is your horizontal distance).


Review for Exam 1


Scale bar length = 100

miles Contour Interval = 50 feet

Elevation of point Q = 583 feet


Next, Measure the heights of points R and T.Label the contours taking into account the contour interval = 50 ft and the elevation of point Q = 583 ft

Protractor


2)Measure the heights of points R and T and find the difference between them (this is your vertical difference).R = 500 ft, T = 400 ft Difference is 100ft.

Protractor

Scale bar length = 100 mContour Interval = 50 feetElevation of point Q = 583 feet Start Point: Q End Point: R

Review for Exam 1



Review for Exam 1


►Remember: Gradient or steepness between two points is the difference in elevation (ED) divided by the horizontal distance (HD):

To Calculate Gradient:(Using the numbers from the previous slides)

ED (difference in elevation)= 100 feet

HD (horizontal distance) = 884 miles

100ft

884miles

= 0.11 feet/mileGradient= ED =

HD

*Gradient is equivalent to slope (m=y/x)*


What is the elevation (in feet) of contour ‘d’?Answer: 400 ft

Protractor




What is the elevation of contour ‘k’? Answer: 650 feet


Protractor



What is the azimuth direction going from the start point towardsthe end point? Start Point = Q and the End Point = R The direction is about 1.5o (“1.5 degrees”).




Review for Exam 1Maps: Distance

one inch = 2.54 cm

one mile = 5280 feet

What is the distance between points B and F in miles? Answer: The distance between points B and F is 2 ¼ inches


one inch = 2.54cm


What is distance between points B and F in miles:

From the scale we know that 1inch:60,000inches. So for 2 inches on the map we have 120,000 inches on the ground PLUS the .25 inches which equates to 15,000 inches for a total of 2.25inches = 135,000 inches



The distance between points B and F in miles is: Now we convert those 135,000 inches to feet to miles


one inch = 2.54 cm




one inch = 2.54 cm


What is the distance between points A and C in kilometers?

The distance in inches from point A to point C is 1 9/16 inches


What is the distance between points A and C in kilometers?First lets see how many map units make up 1 9/16 inches.


one inch = 2.54 cm


1 9/16 = 1

X 60,000

Solve for X by cross multiplying: 1.5625 * 60,000 = 93,780 inches


Review for Exam 1

Maps: Distance

What is the distance between points A and C in kilometers?Now we convert 93,780 inches into FEET, then into MILES and finally Miles into KILOMETERS.


Review for Exam 1Maps: Topographic

Features

Overhanging Cliff

Gentle Slope-widely space contours

Hill

Steep Slope-narrow spaced contours

Closed Depression



Match the following contours with the

appropriate profiles:



Match the following contours with the

appropriate profiles:

1 B

2 E

3 D

4 C

5 F

6 A


Review for Exam 1

What is an outcrop?

What is bedrock?

What is the differences between the two?

►Bedrock is a layer of undisturbed rock usually located beneath a surface layer of soil or other material.

►A surface exposure of bedrock is called an outcrop.


Review for Exam 1Geologic Map

Examine the geologic map to the left.

The numbered rectangles represent different outcrops of bedrock. Assume that each of the individual formations maintains a more or less constant thickness throughout the region.

Then connect the same formations.

http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/geologic_maps/geologic_maps_menu2.html


At drill hole E we hit Formation 1

At drill hole A we hit Formation 2

At drill hole D we hit what Formation??

Review for Exam 1Geologic Map

**Please keep in mind you must be consistent with the thicknesses of the beds as you draw your line connecting Formations.


Review for Exam 1Locations w/in the NYC Metropolitan Area

Know all of the locations marked on the map.

http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/geography/geog_nyc_menu2.html


Review for Exam 1Longitude and Latitude

http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/latlong_menu.html



Answer:Latitude (Horizontal) 5o 59’ 45” North

Longitude (Vertical) 71o 00’ 00” West

What is the latitude and longitude at point J?

Determining the latitude and longitude of a point

http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/angmeas.html



What is the latitude and longitude at point H?

For the latitude: (pink arrows)

We see that point H is between 5o 59’ 45” and 6o 00’ 00” so we have 15” in between. We take half of 15” which is about 8” and add those 8” to 45” to get a latitude of 5o 59’ 53”.

For the longitude: (blue arrows)

We see that point H lies between 71o 00’ 00” and 71o 00’ 45” so we have 45” in between. Take half of 45” which is about 23” so we add those seconds to 00” to get a longitude 71o 00’ 23”.

brooklyn college geology department

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