Explain your decision and reasoning on the evidence. Pangea began to break apart about Ma resulting in the formation of the Atlantic Ocean. Using the map in Figure 1. Hint: measure the distance from the easternmost tip of South America to the inside curve of western Africa. By about million years ago, a unique community of plants had evolved, known as the European ora. Fossils of these plants are found in Europe and other areas. Color the areas with these fossils yellow. Fossils of the fern Glossopteris have been found in these locations.
Color the areas with these fossils green. Fossil remains of the half-meter-long fresh or brackish water reptile Mesosaurus. Mesosaurs flourished in the early Mesozoic Era, about million years ago. Mesosaurs had limbs for swimming but could also walk on land.
Other fossil evidence found in rocks along with Mesosaurs indicates that they lived in lakes and coastal bays or estuaries. Color the areas with these fossils blue. Fossil remains of Cynognathus, a land reptile approximately 3 meters long that lived during the Early Mesozoic Era about million years ago.
It was a weak swimmer. Color the areas with these fossils orange. Fossil evidence of the Early Mesozoic, land-dwelling reptile Lystrosaurus. They reproduced by laying eggs on land. Also, their anatomy suggests that these animals were probably very poor swimmers. Color the areas with these fossils brown. Please note that many red dots are overlaid by green dots on this map.
Using observational and critical thinking skills, answer the following questions: Observe the patterns amongst the earthquake and volcano location maps Figures 1. Hypothesize where you think the major plate boundaries exist and draw those boundaries on the blank map in Figure 1. Which type of boundary divergent, convergent, or transform is the most abundant?
Is there any evidence in the earthquake and volcanic activity that suggests this fault did not always have transform motion? Connect the plotted points to create an approximate cross-section of the subduction zone at the two locations. Look at the graph you made, which region has a steeper subduction angle, the Chile-Peru border or central Chile? In which location do you think volcanoes are closer to the coastline?
Boundaries marked with triangles represent convergent zones. Two arrows in opposing directions indicate divergent boundaries. Transform boundaries have arrows showing motion to both right and left. Red and white colors represent high elevations, greens and yellow represent lower elevations, and purple and blue represent areas below sea level.
Image credit: Tectonic boundary map drawn using GPlates software. Table 1. For the topographic profiles in Table 1. Pay close attention to the y-axis versus x-axis. On each profile, draw the location of the boundary between the two plates.
You can show this as a single line. Indicate which direction each tectonic plate is moving you can use arrows for this. Over time mountain ranges are weathered and eroded, and the topography slowly goes back to base level. Which do you think is more likely to be older, a mountain belt with higher elevations or a mountain belt with lower elevations? Explain your reasoning. Look at the topographic map for part of North America Figure 1. Mark two areas that you think have been through major convergence of tectonic plates.
Which of the two areas do you think is older? What evidence from the map supports your hypothesis? Look closely at the western portion of the North American continent. You should be able to notice differences in the patterns that make up the mountains.
Each pattern represents a different geologic region. Draw boundaries on the map that separate these different geologic regions and then describe the patterns you observed to distinguish them Hint: There are at least three. Tectonic plate activity is often associated with mountain building. On the topographic map of Australia Figure 1. Explain your reasoning for marking this area.
Critical Thinking: Both of these maps contain areas on continents that are below sea level. Come up with a hypothesis that explains how this can happen. Red and white colors represent high elevations, greens and yellow represent lower elevation, and purple and blue represent areas below sea level.
Plate tectonics is the grand, unifying theory of Earth sciences, combining the concepts of continental drift and sea-floor spreading into one holistic theory that explains many of the major structural features of the Earth's surface. It explains why the oceanic lithosphere is never older than about Ma and why only the continents have preserved the Earth's geological record for the past Ma. It provides the framework to explain the distribution of earthquakes and volcanoes and a mechanism for the slow drift of the continents across the Earth's surface.
The theory has now reached such a level of scientific acceptance that the movement of plates, both relative to one another and to the hot-spot reference frame, are being used to infer movement of the hot-spot reference frame with respect to the Earth's rotational axis.
Plate tectonics is an expression of the convective regime in the underlying mantle, but the link between individual convection cells and plate boundaries is not direct because plate boundaries are not fixed and, like the plates, move relative to one another. Plate movements are driven by gravity, largely by cold, dense lithospheric slabs pulling younger lithosphere towards a destructive boundary.
A less-powerful driving force is generated by the potential energy of spreading centres, elevated some km above the general level of the abyssal plains. As ideas concerning plate tectonics have evolved since the s, it has become apparent that while the theory can be applied rigorously to the oceans, the same cannot be said of the continents. Because of the strength and rigidity of oceanic plates, deformation is focused into narrow linear zones along plate margins.
By contrast, when continental lithosphere approaches a plate boundary, deformation can extend hundreds of kilometres into the continental interior because continental plates are less strong. Such deformation gives rise to the major mountain belts of the Earth, as exemplified by the Alpine Himalayan Chain. As you work through this course you will need various resources to help you complete some of the activities.
Making the decision to study can be a big step, which is why you'll want a trusted University. Take a look at all Open University courses. If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module , or a module which allows you to count your previous learning towards an Open University qualification.
Read our guide on Where to take your learning next for more information. Subduction zones, or convergent margins, are one of the three types of plate boundaries. At subduction zones, a convergent boundary occurs when two tectonic plates push together.
When an ocean plate and a continental plate collide, the ocean plate slides under the continental plate, and bends downward. A divergent margin occurs when two plates are spreading apart, as at seafloor ridges or continental rift zones such as the East Africa Rift.
Transform margins mark slip-sliding plates, such as California's San Andreas fault. The San Andreas fault marks the location where the North America and Pacific plates grind past each other in a horizontal motion.
The many tectonic plates shift and interact all the time. Earthquakes, volcanoes and mountains are the result of this process. Nothing can prevent the next major California earthquake from happening.
The key to being safe during an earthquake is preparation. While an earthquake safety kit will be of help after an earthquake, the planning conversations you have with your family members before an earthquake are most important. Create an earthquake safety plan for you and your loved ones. CEA offers premium discounts for houses and mobilehomes that have been retrofitted. Find about the potential geologic threats to your home in case of a major earthquake.
The violent shaking from earthquakes can:.
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