June's place Gravel Pit Site: Clarksville
Vocabulary
Cleavage (rock)
Delta
Gradient
Humus
Outwash
Overburden
Regolith
Residual Soil
Sediments
Soil
Soil Horizons
Soil Profile
Sorting
Stream Bed Profile
Till
Transported Soil
1
Elevation: 227.7 meters Latitude: 42° 34’’ 39’N
Longitude: 73° 57’ 57’’W
Activities
1) Write a description of the five rock samples provided in the kit. Focus on size,
shape, texture, color, and any unique features of the rock sample.
Sample 1
Sample 2
Sample 3
Sample 4
Sample 5
2) Identify what agent of erosion (Water, Wind, or Glacier) deposited the following soil
samples:
Sample #1 Sample # 2Sample #3Sample #4Sample #5-
3) Referring to the vocabulary words for “till” and “transported soil”, what explains the
diverse origins of rock samples located in June’s Gravel Pit?
4) Looking at pictures from the Field Study Site in Clarksville determine what agent of
erosion (water, wind, or glacier) deposited the sediments in different parts of June’s
Gravel Pit.
Gravel Pit Location #1Gravel Pit Location #22
5) Describe the series of events that occurred to created Gravel Pit Location #3.
6) Make a sketch of sorted sediments and unsorted sediments.
Sorted
Unsorted
7) A typical soil profile is created from the bedrock at an average rate of 1cm per 400
years. When a soil profile is complete it is called mature. A mature soil profile has
an A-horizon at the top with humus and minerals, a B-horizon with only minerals,
and a C-horizon with no organic or mineral content.
In New York State because of the relatively recent Ice Age, our soil profile is
immature, missing the B-Horizon.
Sketch and label the layers of the soil profile (1+2) from June’s Gravel Pit.
June’s G.P. Sketch
3
Onesquethaw Creek Stations 1 through 6
Vocabulary
Abrasion
Anticline
Bedrock
Carbonic Acid
Caves (Joint)
Chemical Weathering
Chert
Cross Section
Differential Weathering
Fault (geology)
Fold
Fossil
Joint (geology)
Physical Weathering
Outcrop
Potholes (geology)
Relative Age
Ripple Marks
Root Wedging
Solution Channels
Strata (geology)
Stream Bed
Superposition (Principle of)
Syncline
Uniformitarianism
Station #1: Gradient vs. Velocity
Elevation: _200.6 meters
Latitude: _42o34’29” N_
Longitude: _73o57’50” W_
Factors Affecting Transportation of Sediments
Running water is the primary agent of erosion on Earth. Most running water is found in
streams and rivers. There are many factors that affect the movement of sediments in a
stream. Gradient (slope), discharge, and channel shape influence a stream’s velocity.
Sediments carried by a stream become rounded due to the grinding action of the water on
the rocks, a process called abrasion. The average velocity (speed) of a stream depends
on its slope and discharge, which in turn help to explain the carrying power of a stream.
As the velocity of the stream water increases, the size of the particles carried in the
stream also increases, a direct relationship.
Streams carry materials in 4 distinct ways:
Floatation - floating of particles less dense than water
Solution - dissolved particles
Suspension - tiny particles can travel within the water without touching the stream bed
Bed Load - bouncing (saltation) and dragging (traction) of sediments along the stream
bed
View the following:
Powerpoint of Jake stick Use
Video of Eye Level
Station 1 Photos from the Field Trip
Activities
1) In this activity students measure the velocity and gradient of the stream at two
different locations. Location A is the upstream location. The table on the next page must
be completed in its entirety using the steps in this process and the data given.
Each student is assigned to either the Location A team or the Location B team.
You are assigned to the Location A team.
(a) Determine the gradient of the stream for location A – Students will determine the
gradient using jake sticks, sight levels, and a tape measure.
1. Using the tape measure the students assigned to Location A determine the
horizontal distance between the two canisters representing the start and finish points to
be 25.8 meters. Enter this data in the table below in the appropriate space.
2. The student with the sight level determines their eye height to be 155 cm for the
Location A team. Enter this data as the starting elevations in the appropriate space.
3. The student with the sight level stands at the starting point while the student with
the jake stick stands at the finish point. The person with the sight level determines the
new jake stick reading to be 209 cm. Enter this data as the finish elevation in the table.
4. Complete the calculation for change in elevation and stream gradient (use the
formula found on the front cover of the Earth Science Reference Tables) and enter them
into the table. The first four columns of line one in the table should now be complete.
5. Since only one reading for the gradient is taken, no average needs to be
calculated. Therefore, enter the same data for columns 1-4 on line 4 of the table as well.
b) Determine the velocity of the stream for location A – Students will determine the
velocity of the stream using ping pong balls, a timer, and a net. The same distance will
be used as determined for the gradient.
1. The velocity of the stream is determined over the same distance as for the
gradient. Convert the distance measured (25.8 meters) to centimeters and enter that
data in the table on lines 1-4 since it remains the same for all three trials.
2. A student drops a ping pong ball (or orange) into the fastest moving part of the
stream at the starting point. A student simultaneously starts the timer.
3. When the ping pong ball (or orange) reaches the finish point the timer is
stopped and the ping pong ball is caught in a net.
4. This process is repeated with two more ping pong balls.
5. The times are as follows: Trial 1 = 23.90 seconds
Trial 2 = 25.32 seconds
Trial 3 = 26.25 seconds
Enter this data as the travel times on lines 1-3 of the table.
Determine the stream velocity for each of the three trials using the rate of change formula
found on the front cover of the Earth Science Reference Tables.
Complete line four of the table by finding the average values for trials 1-3.
c) Complete the table for Location B using the data provided.
elev.
start
(cm)
elev.
finish
(cm)
change distance stream travel time distance
in elev (horiz.) gradient (sec)
(horiz.)
(cm)
(m)
(cm/m)
in cm. !!
location A / 1
location A / 2
XXXX
XXXX
XXXX
XXXX
XXXX
location A / 3
XXXX
XXXX
XXXX
XXXX
XXXX
location B / 1
160
275
location B / 2
XXXX
XXXX
XXXX
XXXX
XXXX
11.55
location B / 3
XXXX
XXXX
XXXX
XXXX
XXXX
12.35
location A
(average)
location B
(average)
30.24
13.90
stream
velocity
(cm/sec)
2) (a) Using the data from your chart on the previous page, and the Earth
Science Reference Table page 6 “Relationship of Transported Particle Size to
Water Velocity” graph, determine the size of the sediment the stream could carry
at locations A and B. Record both sizes below:
Size of particle that should be carried in location A: _________ cm
Size of particle that should be carried in location B: _________ cm
Draw to scale a sediment with the maximum size that could be transported at
Location A and Location B in the space below
Location A
Location B
(b) Using a ruler the students found pieces of sediment of the approximate
sizes that the chart showed could be transported. They took the sediment
samples to the stream, dropped them in one at a time and observed what
happened.
Here are their results:
Location A: Of two particles, one particle failed to move, the other bounced
downstream along the bottom.
Location B: Of two particles, one particle failed to move, the other rolled
downstream along the bottom.
Questions - Station #1
1) (a) How did the velocity of the stream at Location A compare to Location B?
(b) The stream discharge at both locations is the same. In light of this, explain
the difference in the velocities below.
2) (a) How did the size of the sediment that could be carried by the stream at
location A compare to location B?
(b) Explain the difference in the size of sediment that can be transported.
3) (a) Did all the sediments dropped in the stream keep moving?
(b) Assuming that the student calculations and measurements were correct,
what factors might account for sediments that were not carried? (Hint: Carefully
examine ESRT page 6)
(c) By what method did sediments of the maximize size that were transported
at Locations A and B move?
Location A:
Location B:
4) State the relationship that exists between:
a) gradient and velocity:
b) velocity and particle size carried by stream:
Station #2: Swirls and Cracks
Activities
1) Make both a rubbing and a sketch of the swirls from the bedrock sample. (sample
provided in the kit) Label your results (Zoophycus- Schoharie grit worm).
Rubbing:
Sketch:
1
2) Make several observations to describe the properties of the solid bedrock you see at
this station: (other examples- Solid bedrock, Bedrock)
3) Measure and record the acute angle(on the picture) between the joint cracks with a
protractor.
_______°
4) a) Watch the Acid Demo (here)
Remember-Marble is made from Limestone which is made from Calcite(CaCO3)
Dolostone is made from Dolomite*
b) Perform an acid test on the back of the hand sample in the kit.
____ Acid bubbled right away with lots of bubbles
____ Needed to be scratched with a nail to get it to bubble, minor bubbling
____ Never bubbled
CaCO3 + 2HCl
Calcite
(Calcium Carbonate)
→ CaCl2 + CO2 + H2O
Hydrochloric
Acid
Calcium
Chloride
Carbon
Dioxide
Water
CaMg(CO3)2 + 4HCl → CaCl2 + MgCl2 + 2CO2 + 2H2 O
Dolomite
(Magnesium/Calcium Carbonate)
magnesium
chloride
5) What is the difference between a trace fossil and a body fossil?
6) Is the fossil evidence observed at this station a trace fossil or a body fossil?
Questions - Station #2
2
1) What do you think the swirls are?
2) How were the swirls created (starting with loose sediments and ending with solid
rock with swirls)?
3) Compare and contrast the rocks you observed at the gravel pit by June’s Place
with the rocks at this site (the creek- station 2: swirls).
(a) After observing some of the rocks at the gravel pit and the rock here at Station 2,
do you think the sediment at the gravel pit is transported or residual? (See Definitions)
(b) Support your answer:
Where is the overburden at the creek - station 2 (swirls)?
Explain your answer.
6) (a) Which site, the gravel pit at June’s Place or the swirls by the creek is older?
(b) Explain how you infer this:
7) (a) What is the name for the long cracks in the bedrock at this site (swirls)?
3
(b) Suggest how these cracks were formed:
8) View this document and use page 7 on the Earth Science Reference Tables(a) Suggest a possible rock group, subgroup, and name for the bedrock at the
creek - station 2 (example: metamorphic, foliated, gneiss):
(b) Why did you choose that type (hint: look at grain size or texture)?
4
Station #3: Boulder and Tree
Activities
Link to the following photos of the boulders located at Station #3.
Sketch drawings for each photo in the space provided.
The boulder contains both light and dark materials. The dark material is composed of
chert. Be sure to show both materials in your drawing.
Top of Boulder
Close up of solution channel
Side of Boulder
Fossil in Boulder
Perform an acid test on the hand sample from the boulder. Test both the
chert (dark colored) and the lighter colored material.
(a) Which of the following occurred on the chert?
____ Acid bubbled right away with lots of bubbles
____ Needed to be scratched with a knife/nail to get it to bubble, minor bubbling
____ Never bubbled
(b) Which of the following occurred on the light colored material?
____ Acid bubbled right away with lots of bubbles
____ Needed to be scratched with a knife/nail to get it to bubble, minor bubbling
____ Never bubbled
What do the results indicate about the composition of each of the materials?
What do the results indicate about each material’s resistance to weathering?
Read the following information on acid rain. Use this information to give a
detailed explanation for how the solution channels formed on the boulder.
5) Make several detailed observations of the tree (Sketch it here as viewed
looking downstream):
Questions - Station 3
1) Give a detailed explanation for the formation of solution channels.
Visit the following sites to see an animation of cave formation:
http://www.classzone.com/books/earth_science/terc/content/visualizations/es140
5/es1405page01.cfm?chapter_no=visualization
http://www.pbs.org/wgbh/nova/caves/form.html
2) How does your explanation for question 1 (above) and the animation, help to
explain the formation of the many caves in this area?
3) (a) How is chert nodule formation similar to how stalactites are formed?
(b) Using the boulder with the nodules, explain the concept of differential
weathering.
Cephalopod Reading:
Cephalopods are an ancient group that appeared some time in the late Cambrian
period several million years before the first primitive fish began swimming in the
ocean. Scientists believe that the ancestors of modern cephalopods (Subclass
Coleoidea: octopus, squid, and cuttlefish) diverged from the primitive externallyshelled Nautiloidea (Nautilus) very early - perhaps in the Ordovician, some 438
million years ago. How long ago was this? To put this into perspective, this is
before the first mammals appeared, before vertebrates invaded land and even
before there were fish in the ocean and upright plants on land! Thus, nautilus is
very different from modern cephalopods in terms of morphology and life history.
-http://www.thecephalopodpage.org/
(a) Identify the fossil in the boulder.
(b) What does the fossil tell you about the environment in which the rock was
formed?
(c) What does this fossil tell you about the type of rock in which it’s found?
5) (a) Why do the tree roots appear to grow out in mid air along the stream walls?
(b) Why are some of these roots flattened?
6) List and describe the weathering and erosional processes that are taking place
with the bedrock containing the tree roots in the table below.
Physical Weathering
Chemical Weathering
Erosional Processes
Station #4: Pot holes / Profiles / Groundwater
At this location on the field trip, students observe potholes that have been carved
in the streambed by the action of moving water. Begin by viewing the pothole picture
show. The first picture is a view of station 4 with potholes visible in the streambed as we
approach it from downstream. Pictures 2, 3, 4, and 5 are close ups of the potholes.
Water running downstream provides enough force to begin a whirling motion of
rock fragments that fall into a small depression. As the rock fragments are swirled and
bump into each other, they carve the bedrock of the streambed, making the depression
deeper and larger. If you look carefully through the glare of picture 5 in the above link,
you can see the rock fragments (called scouring stones) presently caught in the pothole.
New rock fragments tumble into the pothole as older ones move on or are worn away,
enabling the grinding process to continue. At this location, the water is only flowing fast
enough for the scouring stones to be swirled when the water in the stream is very high.
In the pictures, the stream is not moving fast enough for pothole formation to be taking
place.
Pothole Activities
These activities attempt to mimic the process of pothole formation:
1) a) In the lower margin of this page, move your pen around in a 1/4" diameter circle
for 1 minute and describe what happens below:
How many layers of paper did your pen tear through?
b) Get two pieces of rock – one pebble and one cobble. This time rub the pebble in
a small circle on the cobble for 1 minute. Describe the results below:
Water Sources at this station Examine picture 6 in the pothole picture show. In this
picture the stream is seen in the foreground. If you look at the far side of the stream
there is a tree with a hollow at its base near the center of the photo. Look carefully and
you will see that water from an underground stream flows onto the surface from this
small cave.
Looking at picture 6 estimate the percentage of water entering the stream from the
spring.
_________ %
Profile Activities
Using the techniques learned at school, students determined the profile of the stream
bed at this station. They started approximately 5 meters before the pothole section up
to about 5 meters past the point where they end. Students took 4 readings: the starting
point, the base of the pothole section, the top of the pothole section, and the finish point.
(see diagram below). Readings were taken in cm/m (centimeters per meter). Actual
student data has been recorded in the data chart on the following page for you to use.
Reading
4
Reading
3
Reading
2
Reading
1
Finish
Pothole
section
begins
Start
Pothole
section
ends
3) a) Complete the table
Flag
#
1
Distance
From
Previous
Flag (m)
0
Total
Distance
(m)
2
9.2
48
3
5.3
74
4
2.4
92
0
Jakestick
Reading (cm)
166
Reference Level =
Eye Height of Viewer
Change In Jake
Stick Reading
From Reference
(cm)
N/A
Difference in
Elevation from
Last Reading
(cm)
N/A
Elevation of this
Location (cm)
19,659
3) b) Draw the profile for the data represented by the table using an appropriate scale.
Be sure to properly label the axes.
Questions- Station #4
1) (a) What does the paper represent in the pothole activity?
(b) What does the pen represent?
2) Describe the process by which potholes are created.
3) What evidence do you observe for this process having taken place?
4) From completing activity 1b, what might you infer about the length of
time it takes to form a pothole?
Explain:
5) (a) Calculate the gradient between flag 1 and flag 4 at Station 4 in the space below:
(Show all work and units)
(b) Record the gradients calculated for the stream at Station 1 below.
Station 1, location A gradient ____________________
Station 1, location B gradient ____________________
(c) How do these differences in gradient between Stations 1 and 4 help explain the
presence of potholes at Station 4 and their absence at Station 1?
6) (a) Does the surface water from the stream account for all of the water in the
pothole area?
(b) Based on your observations of the running water at this station, where is this
water coming from?
Station #5: The “Stadium”
Activities
1) Link to the following photos of the “Stadium”.
2) Sketch drawings for each photo in the space provided.
Sketch and label section of the outcrop showing a multiple fold, with an anticline and
syncline
Sketch a cross-section across the stream through the center of the stadium as you look
downstream
2) (a) Using your field study packet, apply a force that would create the same
folding pattern as you’ve seen in the rocks at this station.
(b) Make a drawing that shows how forces cause this type of folding.
3) Find the large limestone block on the far right side of the stadium (as you
face the high wall). Suggest how it got to its present position and orientation:
Questions- Station #5:
1) Based on your sketches, teacher discussions, and your knowledge of rock
formation, describe the terms below and explain how each has played a role in
the stadium’s formation and appearance today (ex: if you found mudcracks that
might indicate there was once water present, silt or mud was deposited, the
temperature rose evaporating
the water, etc.):
(a) the limestone:
(b) ripples:
(c) faulting:
(d) folds:
(e) erosional agents.
2) Relative date the following from oldest (1) to youngest (3):
____faulting and folding
____strata formation
____ joint caves
3) Explain how joint caves are formed. Include a sequential diagram in your
explanation:
Station #6: Upstream Cracks
Activities
1) Describe, with as much detail as possible, the appearance of the cracks in
the bedrock at this station:
2) Perform an acid test on the rock sample in the kit from this site: Which of the
following occurred:
____ Acid bubbled right away with lots of bubbles
____ Needed to be scratched with a nail to get it to bubble, minor bubbling
____ Never bubbled
Questions- Station #6
1) Compare each of the following to those at Station 2 (swirls):
Site Number
Station 2
Station 6
Crack Widths
Crack Depths
Acid Test Results
Rock Type
3) (a) How do the angle, width, and depth measurements of the cracks in the
bedrock at Stations 2 & 6 compare to each other?
(b) How do you explain these results?
3) What evidence do you see around this station or from other stations that
suggest humans have an impact on the area?