Understanding Plate Tectonics: Concepts and Landforms Analysis

Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. This lab covers the mechanisms of plate tectonics and the resulting landforms and events we see and feel on Earth’s surface. At the end of this lab you should be able to: 1) Explain the theory of plate tectonics in your own words 2) Summarize the reasons for different plate boundary interactions and describe the resulting surface landforms and events. 3) Evaluate where on Earth’s surface we have plate boundaries and describe the processes happening at these boundaries. 4) Use current landforms on Earth’s surface to classify former plate boundaries. You should start by watching three videos on iCollege: Wegener and Continental Drift, Sea Floor Spreading Proof, and Plate Tectonics. The work your way through these questions, referring back to the videos as needed. Part 1: Plate Tectonics 1) In the above diagram, arrows denote the direction of movement of the crust and mantle, with numbers and letters above each boundary between plates. Name each numbered plate boundary, and what types of plates are involved. (15 pts) Name of the numbered plate boundary what types of plates are involved 1 Convergent Plate Boundary Oceanic plate is subducting beneath another oceanic plate 2 Divergent Plate Boundary Ocean-ocean divergence 3 Convergent Plate Boundary Oceanic plate subducting beneath continental plate 4 Divergent Plate Boundary Continent-continent divergence 5 Convergent Plate Boundary Continental-continental divergence

Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. 2) Name the lettered bathymetric (sea-floor) features in the figure above that are created by plate tectonics (2 pts) A: Trench B: Ridge 3) Describe in your own words the following plate boundaries. Where on Earth would you expect to find an example of each boundary? (6 pts) Convergent: Two plates clash as they drive in one other. This can result in one oceanic plate subducting or both plates colliding and pushing up together. The Mariana Trench is one example. Divergent: Due to molten rock erupting from the mantle, which causes new crust to develop, two plates move apart from each other. Divergence can be seen in the Gulf of Aden or the Great Rift Valley. Transform: Two plates are sliding past one another. The San Andreas Fault is an example of a transform. 4) Name two ways oceanic crust differs from continental crust? (2 pts) Oceanic crust varies from continental crust in that it is thinner and denser. 5) Thinking back to your igneous rock labs, what two elements might account for these differences? (2 pts) As a result, the two variables that differ are density and composition.

Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. 6) Look at the above image and answer the following questions (hint: Ma means Mega- annum, or millions of years) a. Where is the oldest oceanic crust in the Atlantic? (1 pt) Oldest crust in the Atlantic is found near the continental margins that are in the Abyssal Plains. About 260 years old. b. Where is the youngest oceanic crust in the Atlantic? (1 pt) The youngest oceanic crust is present along the center of the mid-Atlantic ridge, 10 MA. c. Explain why this variation in the age of the oceanic crust exists across the Atlantic Ocean. (2 pts) The diverging boundary at MAR causes the variation. The older crust pushes outward while the fresh crust grows from the MAR. d. The feature in the middle of the Atlantic Ocean is called the Mid-Atlantic Ridge. Given your responses to the above questions, is this a convergent, divergent, or transform boundary? (1 pt) Because the plates are moving apart from each other, the Mid-Atlantic Ridge is a divergent boundary.

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Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova ………………….

Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. Earthquakes distribution

Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. 8) Using the above maps of volcanos and earthquakes, answer the following questions: a. Which of the following has high concentrations of volcanos? Mark all that apply. (4 pts) ___ Eastern Atlantic Ocean _X__ Eastern Pacific Ocean ___ Hawaii ___ Western Atlantic Ocean _X__ Western Pacific Ocean ___ Iceland b. One of the oceans in the world is referred to as the “Ring of Fire” – which might it be and why? (4 pts) The Pacific Ocean is the site of the Ring of Fire. The nickname given is because a significant amount of volcanic eruptions and earthquakes occur along this path due to the presence of several active volcanoes and seismic activity such as earthquakes. c. Given your responses to the above questions, is a convergent, divergent, or transform boundary represented in locations that have volcanic activity and high concentrations of earthquakes? (2 pts) Divergent boundaries are those when two lithospheric plates migrate apart from one another, resulting in the creation of a ridge. Normal and transform faults, as well as the occurrence of shallow-focus earthquakes, may be found in this sort of plate boundary.

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Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. Part 2: Plate Tectonics and Landforms 12)Rocky Mountains The Rocky Mountains formed during the closure of the Cretaceous Interior Seaway, a shallow sea between North America and an archipelago in the Pacific Ocean. What kind of boundary is this? (2 pts) A convergent boundary between the Pacific Oceanic Plate and the North American continental plate.

Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. 13) Jordan Valley and the Dead Sea The Jordan Valley in the Levant is composed of the Sea of Galilee, which flows into the Jordan River, and eventually into the super salty Dead Sea. This valley is at the boundary of the African and Arabian plates. The valley is composed of sediments that have eroded into the space between the two plates, and the valley is so deep that the Dead Sea is below sea level! What kind of boundary is this? (2 pts) This is a Divergent Plate boundary between the African and Arabian continental plates.

Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. 14) The Ural Mountains The Ural Mountains in central Russia are some of the oldest mountains in the world. They are near no plate boundaries, no earthquake activity, and essentially in the middle of the Eurasian plate. Hypothesize how they formed, keep in mind from the Hawaii example in the lecture that plate movement can change over time. (4 pts) The Ural Mountains were formed by the convergence of two former continental plates (convergent boundary) from Asia and Europe. The plate Boundary fused these two parts together when plates collided.

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Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. 15) Lake Superior Lake Superior is an exceptionally deep lake north of Michigan’s Upper Peninsula. While the other Great Lakes are much shallower and are hypothesized to be formed from retreating glaciers at the end of the ice age, scientists suspect something different for Lake Superior. It should be noted that ages of the rocks in Isle Royale and the Keweenaw Peninsula (both colored orange and green on the East side of the map) have mirrored ages in their rocks, getting older further away from each other. Hypothesize how Lake Superior formed (4 pts) Fault lines and rift valleys developed. The low-lying area where the crack formed would thereafter have been the source of collected water from runoff and other sources. These two portions were fused together by the plate boundary where the plates met.

Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. 16) Mid Ocean Ridge You know that Mid Ocean Ridges are created from Divergent boundaries. However, you may have noticed that they only form straight lines for a while and are quite jagged. This is the result of trying to split apart curved surfaces. This implies another kind of fault is also at play here. If the crust is spreading away from each of the green lines, which other fault type/boundary is present here? (1 pt) When the plates glide past one another, a transform fault occurs.

Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. 17) Iceland The island of Iceland in the North Atlantic is formed from a hot spot/mantle plume just the same as Hawaii. However, we don’t see an island chain, only a singular large island. Why might this be? (4 pt) The only continent where a mid-oceanic ridge is present above the continental region is Iceland. There are no volcanic island chains or hotspot-type activity since the environment is that of a divergent or mid-oceanic ridge. Part 3: Seismic Explorer Go to the following website to complete the final activity: https://seismic-explorer.concord.org/ Click “Map Type” and choose “Relief”. Click “Data Type” and have both “Plate Boundaries” and “Earthquakes” enabled

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Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. Hit “Start” in the lower left. This will show major earthquakes over time. Answer the following questions: 1. What patterns in the locations of earthquakes do you observe? (1 pt) According to the patterns of earthquake locations, there are earthquakes anywhere there are plate boundaries. 2. Red dots are shallow earthquakes while blue dots are deeper. What areas of the world have blue dots? What plate boundaries are these? (2 pts) These areas have deep earthquakes, which indicates that there is a convergent plate boundary due to the subduction of one tectonic plate beneath another. Click “Draw Cross Section” in the lower right. Draw a cross section with it covering part of western South America with both red and blue dots, going from red (P1) to blue (P2). Then click “Open 3D View” in the lower right. 3. Describe the relationship (trend) between depth of earthquakes and distance from plate boundary. (1 pt) They are parallel to or in line with the boundary from which they arise. Additionally, depth produces a pattern that indicates the position and amount of tension at the border. Close the 3D view and cancel cross section drawing. In “Data Type” enable “Plate Movement” and “Plate Names” and disable “Earthquakes”. Each “i” if clicked on will show the speed of movement and boundary name (e.g., “COC-NAZ”). 4. Click around these “i”’s. Which plate boundary in the Pacific Ocean is moving the fastest? (2 pts) Pacific ocean-pacific plate & Nazca Plate are the boundaries that move the fastest and are also the ones who are moving away from each other, which creates a divergent boundary. 5. Even this fast plate above doesn’t have uniform speed or direction across all its boundaries. Hypothesize why below. Keep in mind all plates are moving independently of each other and all speeds are relative to the opposing plate. (2 pts) This might be the cause because the stress points aren't distributed evenly throughout the boundary. Part 4: Summary

Lab 7 – Plate tectonics GEOL 1121 Name … Adelina Ivanova …………………. Fill in the below chart to summarize your understanding of characteristics at different plate boundaries. (10 pts) TYPE DESCRIBE MOVEMENT CRUST Created? Destroyed? Neither? EARTHQUAKES? Shallow? and/or Deep? TYPE OF VOLCANISM? Rifting? Volcanos? WHERE IN WORLD? (EXAMPLES) Divergent Split Apart Created Shallow Rifting Mid-Atlantic Ridge Convergent (Subduction) Under/Over Destroyed Deep Vocanos Pacific Northwest Transform Slide Past Neither Can be both, depends on the geographics None San Andreas Fault

Lab 7 -PlateTectonics_activity (1)

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