Geology Lab Exam II Questions

The topographic map shown below displays the topography and bathymetry of a coastal area. What is the approximate total topographic relief represented in this map? Note: The contour interval is 20 feet.

200 feet

How many formations are present in the image shown? (A photograph of an outcrop. The top rock unit appears to be a limestone or sandstone with several vertical fractures. The middle rock is a grey shale. The lower rock unit is a horizontally bedded limestone.

3

In which direction do the Vs formed by the contour lines point as a stream crosses them?

Upstream

Which of the following glacial features is unique to mountain glaciation?

cirque

What is the name of the glacial feature shown in the image below? (A satellite image of an alpine glacier. Arrow is pointing to a dark stripe down the center of a glacier.)

medial moraine

Using this seismogram, calculate the approximate S-P interval. (drawing of seismogram with minute intervals starting at 8am; first deviation at 8:02:30; second deviation at 8:07:30; strong deviations begin at 8:10)

5 minutes

What is the angle of dip for point C?

50

The topographic map and orthoimage displayed below show the same area. What is an advantage of using an orthoimage combined with other data layers that a topographic map alone does not have?

Details of land use are easy to see.

Label the features associated with meandering streams on the diagram below.

Escarpment Terrace Floodplain Cut Bannk Levee (in order, top to bottom, left to right)

What are the relative ages of the beds in an anticline? If 1 represents the oldest bed, and 4 represents the youngest bed, label the diagram with the ages of the beds.

4, 3, 2, 1, 2, 3, 4

Why has the Nisqually Glacier retreated over the past 100 years?

More snow and ice has been removed than added. The rate of ablation is higher than the rate of accumulation

According to this chart, in what general direction did slip occur?

The motion was both upward and toward the east.

A(n) ______ is the remnant of a former floodplain

terrace

If a rock is dipping due east, what is the direction of strike?

North-south

What is the gradient of the stream from Point A to Point B?The elevation of Point A is 2460 ft above sea level and the elevation of Point B is 2380 ft above sea level. The two points are 2 miles apart.

40 feet/mile

What was the depth of the initial rupture (at the focus)?

Approximately 32 kilometers

Where could oxbow lakes form in the future? (same image but labelled)

DBC

A(n) _______ is a bend in a steep narrow bedrock valley.

incised meander

A compass direction along a line from one point to another that is expressed in degrees east or west or true north or south is a(n) _______________.

quadrant bearing

A(n) __________ is a structure created when a vertical fracture allows blocks of rock to slide horizontally.

strike-slip fault

What is the magnitude of the maximum slip indicated here, in meters?

24

What term describes the tectonic feature along the seafloor at the blue plate boundary at the arrow?

trench

Using the change in elevation from Part D, calculate the straight-line gradient between placemarks G and H. Calculating the slope here is exactly the same as in geometry, divide rise over run.

0.795

What are the relative ages of the beds in a dome? If 1 represents the oldest bed, and 4 represents the youngest bed, label the diagram with the ages of the beds.

1 in the middle. 2, 3, 4 in the outer layers

What is the sinuosity of a stream that has a straight line distance of 2.5 miles and a stream channel length of 4 miles?

1.6

What was the depth of the area of maximum slip?

10-20 kilometers

What are the elevations of placemarks G and H respectively?

5540 feet; 5930 feet, respectively

Which of the following depositional features form parallel to the flow of ice in a glacier?

Esker Drumlin

Which of the following characteristics or features describe the headwaters of a stream?

erosion dominates high elevation and slope/gradient

What does the cross sectional view of this geologic map look like? Label each bed in the cross section as it corresponds to the geologic map below. Label the bed that is not seen at the surface as bed "E". (same picture as above)

A, B, C, E, D, A, B, C, E

Which statement defines stream terrace?

abandoned floodplains

The difference in degrees between due north and magnetic north for a location is that location's ______________.

declination

The map below shows a portion of a topographic quadrangle map. Its horizontal scale is 1:24,000. Suppose you plan to construct a topographic profile from the Puritan Mine to the Red Rover Mine with a vertical scale of one inch equals 60 feet. What will the vertical exaggeration of the topographic profile be?

33.3x

What order stream is the stream at Point B?

3rd

What are the ages of the different beds in this cross section? Use the principles of relative dating to help you determine the relative ages of each bed. (picture is above answer labelled)

Oldest -> Youngest E -> C -> B -> A -> D

Describe the relative motions of the Pacific Plate (east of the boundary) and the Okhotsk Plate (west of the boundary).

The Pacific plate is moving westward and is being subducted under the eastward-moving Okhotsk plate.

A device that can be used to overlap a pair of aerial photographs to form a three-dimensional image is a(n) ____________.

stereoscope

Which kind of directed pressure and confining pressure would result in stretching and thinning of the crust?

tensional stress; ductile confining pressure

The map shown below has a scale of 1:24,000. If a large building has a length of 150.0 feet (actual size on the ground), how many inches long would it be on the map?

0.075 inches

What type of stress caused this body of rock to be deformed? Choose the image that shows directed pressure being correctly applied to the body of rock. (A cross section of a syncline)

The same cross section with arrows pointing inward from the sides only

An image or data layer that has been corrected so that it has the same geometry and scale as a topographic map is a(n) __________ image or layer.

orthorectified

Which stream drainage pattern would consist of a central high elevation region with several streams draining away from it in all compass directions?

radial

Take a moment to think about how the Colorado River has evolved through time. Focus on how changing base level and stream incision created landforms, such as incised meanders and rincons, and arrange these events accordingly.

-Oldest Event- A stream migrates laterally across its floodplain developing meanders. This stream terminates at a lake, which is its base level. The base level of the stream is lowered by crustal uplift and the river begins to incise downward. Incised meanders form. A rincon forms by the cutoff of an incised meander, which shortens the river. -Youngest Event-

A stream is flowing down a slope into a larger river. The elevation of the head of the stream is 1,776 feet above sea level. The elevation of the mouth of the stream is 1,298 feet. The distance between those two points is 15,098 feet. What is the gradient of the slope the stream is flowing over in ft/mi?

167 ft/mi

The latitude-longitude coordinate system provides reference lines from which to measure the location of a point on Earth's surface. For example, Point A is located at 20° north latitude and 120° west longitude. Now determine the latitude and longitude of Point B.

40 degrees south; 20 degrees west

Using the average speed you calculated in Part B (which was 480km/min), how long would it take a P-wave to arrive in New York, NY from an earthquake that occurred in San Francisco, CA (approximately 4675 km away)?

9.75 min

The average rate of movement of the North American Plate and the Pacific Plate is around 2 inches per year near this fault. Which of the statements below explains how this movement is seen along the San Andreas Fault?

Different locations of the fault are displaced at different times Displacement events can be much greater than 2 inches Displacement along the fault occurs sporadically, sometimes with many years between each displacement event.

What information do contour lines provide?

elevation above sea level

This image shows what type of fault? (A photograph of layers of rock offset by a fault. The fault is marked, and the hanging wall has moved down relative to the footwall.)

normal

In the Universal Traverse Mercator System, the distance measured in meters from the Equator is the ____________ coordiante

northing

What is the probability (as a percentage) of a 500-year flood occurring in any given year?

0.2%

Use the arrival times you calculated in Part C to determine on the graph below how far this recording station was from the epicenter of the earthquake. Arrival time of P-wave: 9 minutesArrival time of S-wave: 16.5 minutesS minus P interval: 7.5 minutes On the diagram, the bottom curve is the P-wave arrival time, the middle curve is the S-wave arrival time, and the top curve is the surface wave arrival time.

5800 km

Label the image with the correct strike and dip symbols. (vertical line picture from before)

<<, >> , >< , < (indicate where the short line is pointing)

Convert the average P-wave speed you found in Part B (480 km/min) from km/min to km/sec.

Average P-wave speed = 8 km/sec

Suppose there is an earthquake along the San Andreas fault that originates at the star on the map. If recording stations were located at points A, B, C, D, which seismographs would show compression as the fault moves? (Aerial photograph of a segment of the San Andreas Fault, looking east. On the far side of the fault is the North American plate. Points A and B are on this side of the fault. A is to the left (north), and B is to the right (south). An arrow points from A to B. On the near side of the fault is the Pacific plate. Points C and D are on this side of the fault. Point C is to the left (north), and point D is to the right (south). An arrow points from D to C. A star on the fault denotes the epicenter of an earthquake.)

B C

The water discharge of which of the following cities would have an impact on the water quality in New Orleans?

Chicago, IL Minneapolis, MN Denver, CO Pittsburg, PA

When the Tohoku earthquake occurred, as much as 30 meters of the Pacific plate was subducted westward under the Okhotsk plate, upon which sits the island nation of Japan. The crust of the Okhotsk plate directly west of the plate boundary bulged upward. In light of this, what is a possible explanation for the uplift indicated in red just west of the plate boundary?

During the earthquake, a large part of the Pacific plate was thrust under the Okhotsk plate. This both lifted and deformed the edge of the Okhotsk plate.

Sort the following images in terms of whether or not they were under high or low confining pressure at the time of deformation.

High confining pressure (Ductile deformation): concaved down layers MDS concaved up layers SDM Low confining pressure (brittle deformation): Colorful fractures colorful mountainside with long fracture in the side

Which of the following images shows rock layers that are offset because of deformation?

Photograph of a mountainside in which rocks have been cut by a fault and moved.

This image shows what type of fault (fault K)? (A cross section with several tilted and deformed sedimentary layers, a metamorphic rock, two igneous rocks, three erosional surfaces, and two faults. One fault is circled; on this fault, the hanging wall has moved up relative to the footwall.)

Reverse

Which of the following statements best describes the topography around placemark A and the resulting appearance of the spacing of the contour lines on the map?

The land surface is relatively flat, and the contours are widely spaced.

Which answer most correctly describes the landform at placemark I and the appearance of the contour lines in the area?

The landform is a ridge, and the contour lines form Vs that point downslope.

If the last 100-year flood occurred in a region in the current year, when is the next 100-year flood possible?

The same year

A compass direction along a line from one point to another that is expressed in degrees between 0 and 360 is a(n) ______________.

azimuth bearing.

The lowest level to which a stream can erode is called _______.

base level

Which stream channel type is visible in this figure? (Image of stream with multiple intersecting channels.)

braided stream

If the velocity of a stream decreases, competence __________ and sediment is _____.

decreases, deposited

A __________ defines the area of land that will supply water to a stream.

drainage basin

The flat, broad area surrounding a stream is referred to as a(n) ________.

floodplain

Examples of a local base level include a stream or a(n) _______.

lake

A digitized aerial photograph that has been corrected so that it provides a uniformly perpendicular aerial view that correlates precisely with a topographic map is a(n) ________________.

orthoimage

A pair of aerial photographs that can be viewed side-by-side to form a three-dimensional image is a(n) __________.

stereogram

The Goosenecks of the San Juan River are located in southeast Utah. At this location, the San Juan River has cut a gorge through at least 1,000 feet (300 m) of Paleozoic sedimentary rocks. As mentioned in the video, this region was affected by uplift of the Colorado Plateau during the Cenozoic era. Base level was lowered and this river began to incise downward due to a steepened gradient. A raft on the San Juan would float more than 6 miles to match a crow flying straight for 1.5 miles above this landscape. The Google Earth image and photo below, which depict the same location from different angles, show two features, labeled A and B, that were created by downcutting of the San Juan River. Choose the correct pair of terms from the choices below.

A) incised meanders B) terraces

Create a trace report to determine how many states are part of the Mississippi River watershed.

Ohio River Yellowstone River Arkansas River

Which of the following statements are true about the inside of a meander curve?

Referred to as the point bar Deposition occurs at this location

In what direction did the motion propagate along the plate boundary?

The motion was both upward and toward the east.

Velocity and turbulence are _____ at the __________.

greatest; outside of a meander

Identify the glacial feature indicated by the arrow in this figure. (photo of ice carved into the top of a sheer glacial trough)

hanging valley

In which of the following geologic structures do rock beds dip toward one another?

non-plunging synclines basins plunging synclines

How many states are part of the Mississippi River watershed?

31

Glaciers are significantly large areas of snow-covered ice that move (flow). Which of the following conditions would be suitable for a glacier to form, assuming that sufficient moisture is also present?

High elevation at a high altitude High elevation at a low latitude

The following photo shows a typical cut bank on the Missouri River (iPhone for scale). Note the steep profile with fine-grained sediments above coarser sands and gravels. Which of the following statements are true?

A cut bank is located on the inside of a meander bend

What do all three structures in this figure have in common?

All three are a result of compressional force.

Using the topographic map in the figure, follow along line X-X' and determine what the topographic profile would look like. Choose the appropriate profile below.

Answer: B

How are plate boundaries, stress, and faulting related? For each plate boundary, determine what type of stress occurs at that boundary and what type of faults occur.

Divergent Boundary: -tensional stress -normal fault Convergent Boundary: -compressional stress -reverse fault Transform Boundary: -shear stress -strike-slip fault

Locate the Starved Rock State Park, Illinois. Adjust the zoom so you can see both the lodge and Plum Island, which is northwest of the lodge. What is the approximate distance between the campground and the northwestern tip of Plum Island?

2.1 miles

A topographic map has a ratio scale of 1:250,000. One centimeter on the map equals _____ kilometers in the real world.

2.5

On this map, what is the change in elevation between two adjacent index contour lines? (Answer to the nearest foot.)

200 feet

If the S-P interval is 4 minutes, what is the distance from the epicenter in kilometers? (Time travel graph indicating the S and P wave curves)

2500 km

Assuming a contour interval of 50 feet, what is the elevation of the centermost contour line in this figure? Please observe that the first contour line has an elevation of 100 feet above sea level.

300 feet

Which of the following geologic features are present in this geologic map? (A geologic map with four formations, A through D. There is no indication of which layer is oldest or youngest. Contacts are parallel to each other and are oriented north-south. Sequence of formations from west to east is: A, B, C, B, A, D, A, B.)

Syncline Anticline

Which of the following statements is true regarding the time between the arrival of P and S waves at a given location?

The arrival time difference increases as distance from the epicenter increases.

Which of the following statements are true?

The two rock units on the left are dipping away from the two rock units on the right The two rocks on the right side of the image are dipping toward the east The two rocks on the left side of the image are dipping toward the west

The compass bearing from Point A to Point B on the map below is 232°. If the magnetic declination is 14° west of true north, what is the bearing after it is corrected for magnetic declination?

246 degrees

Look at the topographical map below. Which elevations of the Flint River would cause the Montezuma Post Office to be flooded? Note: The contour interval for this map is 10 foot.

290 foot 300 foot

Below is an image showing part of the Split Mountain Anticline of Dinosaur National Monument, Utah. It is quite large, so we are looking at only a small portion of the anticline's southern flank. In this photo, you can see sedimentary rocks that have been exposed by weathering and erosion. Yellow lines show curved light-colored sandstone beds that are exposed in canyons cut into the anticline. Orange lines point out red- to orange-colored dipping sedimentary beds that have been eroded from the upper part of the anticline. Concentrate on the series of events that led to the formation and exposure of this anticline. Rank the following events in order from OLDEST to YOUNGEST in age.

-Oldest- Sediments are deposited in a horizontal orientation The sediments are buried and lithified into sedimentary rock Compressional forces cause the sedimentary rocks to bend into an anticline Processes of weathering and erosion expose the interior of the anticline

Which of the following diagrams matches the movement of the North American and Pacific plates along the San Andreas Fault?

A map view showing the Pacific plate on the left and North American plate on the right. The Pacific block has moved north relative to the North American block.

Which of the following seismograms show dilation? Which show compression?

Compression first wave points up Dilation first wave points down

What might be a possible explanation for the fact that the there are no volcanoes over areas where the subducted plate is less than 100 kilometers deep?

Magma is not generated in significant amounts until the subducted plate has reached a depth of 100 kilometers.

Rank the dip angles from steepest to most shallow.

Steepest -> Most shallow 70 -> 50 -> 40 -> 35

Which of the following is the correct symbol to represent the strike and dip of the rock units in this image?

T symbol with a long vertical line and a short horizontal line pointing left

In the U.S. Public Land Survey System, the north-south squares are called __________ and the east-west squares are called ____________.

townships, ranges

What is the minimum number of points needed to locate the epicenter of an earthquake?

3

Elevation is measured as height above sea level. Using the contour lines on the map below, rank the labeled areas from lowest to highest elevation. The main contour lines are marked with the number of feet above sea level. The elevation change between the thinner lines is 40

D -> C -> B -> A -> E Lowest -> Highest

How fast do different types of seismic waves travel? Which is the fastest? The slowest?

Fastest -> Slowest P-waves -> S-waves -> Surface waves

The _______ of a fault is the location where slippage between two rocks begins, resulting in an earthquake.

hypocenter

The colored legend at the bottom of the diagram represents the amount of slip experienced along the fault. What was the greatest amount of slip in centimeters and in meters?

more than 3000 centimeters (30 meters)

How many oxbow lakes are present in this image? (A satellite image of an area near Voltaire, North Dakota. A meandering stream and three associated horseshoe-shaped lakes have been highlighted so they are clear on the diagram.)

3

Launch Google Earth™ by clicking on this link to locate the Starved Rock Lodge at Starved Rock State Park, Illinois. If you do not have Google Earth installed, download it at http:/www.google.com/earth/index.html and install it on your computer before you begin. In the Layers Panel on the lower right, make sure the Borders and Labels and Places boxes are checked. Using Placemark A, which of the following is the best estimate of the latitude and longitude of the park in degrees, minutes and seconds?

41 degrees 18' 20 N, 88 degrees 58' 29 W

The curving and dashed lines in the diagram display how much time elapsed between the initiation of the earthquake at the focus and motion experienced along the fault. How many seconds after the initial rupture at the focus did the maximum slip (shown in red) occur?

45-60+ seconds

Calculate the average speed P-waves travel through Earth using the data from the following figure. Use the data from the highlighted stations (Australia, New Guinea, and New Caledonia) to make your calculations.

480 km/min

Which of the following actions would logically result in a lateral moraine?

Glaciers scrape along valley walls, knocking rock loose.

How does the sediment in glacial till compare to the sediment being transported by the braided streams draining away from the terminus?

Sediment in braided streams is well sorted Sediments in till are unsorted.

Which of the following best describes how striations are created?

Sediments frozen in glacial ice abrade the rock

Stream Drainage Patterns

Streams PPT Slide #6

An increase in global mean temperatures could cause which of the following effects?

The amount of melting will increase in many glaciers. The number of glaciers retreating will increase. Some glaciers will completely disappear. Fewer areas on Earth will have climates that support year-round snow and ice, conditions necessary for glaciers to form.

La Cañada Alamosa is a tributary of the Rio Grande, located in central New Mexico. Due to climatic changes, the local base level for this stream was lowered. This occurred many times as evident by the presence of multiple terraces. Rounded gravels present on the terraces represent former channel deposits. Using the following photos, classify the observations according to whether they are "true," or " false."

True: At least two episodes of downcutting have occurred. Rounded gravels provide evidence that these fault-topped features are terraces. False: The local base level for this stream is sea level. Only one terrace is present at La Canada Alamosa

Label different features of a glacier on the diagram below.

Zone of accumulation Snow line Zone of ablation Terminus

Incised meanders and terraces are __________.

erosional features

Think about glaciers changing as a function of mass balance. If more snow and ice are added, it expands. If more melts away, it shrinks and recedes.Fill in the blanks:If accumulation is __________ ablation, the terminus of the glacier will _____.

less than; retreat greater than; advance

Which letter in this figure marks the location of the S-wave? (drawing of seismogram with A label, B label at first pulse of waves, C label at beginning of second pulse, D label at larger deviation and E at largest)

location C

A sweeping bend of a stream which is migrating laterally in a wide, flat valley is called a(n) _______.

meander

In light of your answers to parts D, E, F, G, and H, what is a possible explanation for the uplift indicated in red just west of the plate boundary?

During the earthquake, a large part of the Pacific plate was thrust under the Okhotsk plate. This both lifted and deformed the edge of the Okhotsk plate.

In light of your answers to Parts A and B, explain how the earthquake changed the coastline in a way that increased the destructiveness of the tsunami as it came ashore.

The effective height of the tsunami would have been increased by the amount of subsidence of the coastline: here, around 1 meter.

Which answer most correctly describes the landform at placemark J and the appearance of the contour lines in the area?

The landform is a flat-topped hill, or peak, called a butte. The contour lines form concentric closed loops around the high point.

The topographic map displayed below shows two marked elevations near the bottom of the map. The 266-foot elevation is slightly left of the center of the map and the 24-foot benchmark is on the right side. The distance between the two marked elevations is approximately 1.5 miles. Which of the following is the best estimate of the overall gradient of the land between them?

161 feet/mile

The map below shows a portion of a topographic quadrangle map. The Red Rover Mine, which is located near the center of the map, is labeled by name and marked with a mine shaft symbol (and circled in blue). What is the elevation of the Red Rover Mine?

3360 feet

A common size of U.S. Geological Survey map is a 15-minute quadrangle map, which measures 15 minutes of latitude by 15 minutes of longitude. Below you will use the latitude and longitude of one corner of a 15-minute quadrangle map to determine the latitude and longitude of another corner. Point B is located at 40° south latitude and 20° west longitude. Assuming that Point B is at the northwest corner of a 15-minute quadrangle map, what is the latitude and longitude of the southeast corner of the map?

40 degrees 15' south latitude, 19 degrees 45' west longitude

What is the change in elevation across each contour interval (i.e., between successive "regular" contours) on this map?

40 feet

What is the elevation of the Starved Rock State Park, Illinois? Use Placemark A as reference point. If your elevation in Google Earth™ is any unit besides feet, go to "Tools" > "Options" and change the "Unit of Measurement" unit to "Feet, Miles".

635 feet

Which was updated more recently, the topographic map or the satellite imagery? How can you tell?

The satellite imagery was updated more recently. This is evidenced by roads and buildings that appear in the satellite imagery but not on the topographic map.

The Tohoku earthquake generated a massive tsunami that devastated the nearby coast of Japan. In light of your answer to Part A, what is the explanation for the generation of the tsunami?

The sudden lifting of the seafloor around the bulging crust pushed huge volumes of water up, out, and away in all directions.

Describe the relationship between the location of volcanoes on the island of Japan and the depth to the subducted plate below Japan.

The volcanoes appear to line up along the 100-kilometer dashed depth isoline, and there are more over areas where the plate is deeper. There are no volcanoes over plate that are less than 100 kilometers deep.

This image shows what type of fault? (A cross section with four layers, a fault, and an erosional surface. From the bottom upward, the sequence is: Horizontal layers A, B, and C. Fault D cuts those three layers, and the hanging wall is moved down relative to the footwall. Erosion surface E truncates both the fault and the top horizontal layer. Layer F was deposited on top of erosional surface E. Some cobbles of Layer C are found in Layer F.")

normal

Which of the following images shows a rock that has undergone deformation?

photo of metamorphic rock with layers photo of rock outcrop in which rocks are bowed downward into a broad U shape

Which of the following criteria best fits S-waves? CHOOSE ALL THAT APPLY

shear waves side-to-side motion cannot travel through liquids

Identifying the type of rock in an outcropping and seeing how it has deformed can help to determine the history of the surrounding area. There are three basic types of rock: igneous, sedimentary, and metamorphic. Igneous rocks, such as granite, are directly formed from cooling magma. Sedimentary rocks, such as shale or limestone, are formed by layer upon layer of loose sediment, either from small bits of other inorganic rocks or the remains of living organic creatures, being deposited upon one another. Over time these sediments are turned to stone. Shales are formed by inorganic sedimentation, and limestones are comprised of organic materials. Metamorphic rocks, such as gneiss, slate, or marble, are any type of rock that has undergone extreme heat and pressure and has been transformed into a new type of rock. Gneiss can be formed from granite, slate is formed from shale, and marble is the metamorphic result of heat and pressure being applied to limestone. The outcropping that we are looking at is comprised of marble. Knowing what we know about the principles of geography, go through the statements below and put the events in chronological order from oldest to youngest. Rank the areas identified in the cross section from oldest to youngest.

-First- Formation of limestone in a shallow ocean Pressure and temperature transform limestone into marble Folding of rock Faulting of rock Erosion at the top of the outcrop where plants are growing -Last-

Which of the following could be the notation for the strike of the rock?

25 degrees

Use the Public Land Survey System to locate the X out to three quarters. Assume that it is located in Township 1N and Range 3E.

NE 1/4, NE 1/4, NW 1/4, Sec. 32, T1N, R3E

How do the strikes and dips of rock units in a geologic structure relate to one another? How do these relationships vary in different types of structures?

Strikes will be in similar directions, dips will be in similar directions: Tilted beds Strikes will be in different directions, dips will be in similar directions: none Strikes will be in similar directions, dips will be in different directions: Non-plunging synclines; non-plunging anticlines Strikes will be in different directions, dips will be in different directions: plunging anticlines; plunging synclines

What type of plate boundary is the blue boundary here?

convergent boundary

What kind of structural feature would be represented by the strike and dip symbol pattern in this figure? (Drawing of a hexagon composed of 6 lines, each with shorter perpendicular lines pointing outward).

dome