Question

reading assignment: geologic history
carefully read chapter 10 (pp. 88 to 100) in making connections (posted on our course home page) and answer the questions below. this will help you to review continental drift and plate tectonics as well as give you background information for the geological timeline.
give a very detailed description of the reasons why alfred wegener believed that the continents had drifted apart. (hint - 4 proofs)

1. who came up with a

ew\ theory to continental drift, when did he come up with it, and what was the theory?

1. can you describe a technology now that we have that can actually measure plate motion, explain the technique and give an example of what they found using it.
2. in this chapter they talk about how canada’s landscapes evolved though plate tectonics and the process of \erosion\ breaking down the land that was built up. can you think of, and in as much detail as possible, explain three ways that erosion may have worn down the landscape?

Explanation:

1. Alfred Wegener's reasons for continental - drift belief:

• Geological fit: The coastlines of continents like South America and Africa seem to fit together like puzzle pieces. For example, the bulge of Brazil fits into the Gulf of Guinea.
• Fossil evidence: Identical plant and animal fossils are found on different continents that are now far apart. Glossopteris fossils are found in South America, Africa, India, Antarctica, and Australia, suggesting these continents were once joined.
• Rock - formation correlation: Similar rock formations and mountain ranges are found on different continents. The Appalachian Mountains in North America are similar in age and structure to the Caledonian Mountains in Europe.
• Paleoclimatic evidence: Glacial striations and till deposits are found in regions that are now in warm climates, indicating these areas were once in colder latitudes and the continents have moved.

1. For the new theory of continental drift, the theory of plate tectonics was developed later. It was formulated in the 1960s by many scientists. It combines the concepts of continental drift and seafloor - spreading. It explains that the Earth's lithosphere is divided into tectonic plates that move relative to each other.
2. GPS (Global Positioning System) can measure plate motion. GPS receivers are placed on the Earth's surface at fixed points. By continuously monitoring the position of these points over time, scientists can measure the slow movement of tectonic plates. For example, GPS measurements have shown that the North American and Eurasian plates are moving apart at a rate of about 2.5 centimeters per year.
3. Three ways erosion can wear down the landscape:

• Water erosion: Rainwater can form runoff that carries away soil and rock particles. Rivers can carve out valleys over time, like the Grand Canyon which was formed by the Colorado River's erosion.
• Wind erosion: Wind can pick up and transport sand and small particles. In deserts, wind erosion can create sand dunes and also abrade rock surfaces.
• Glacial erosion: Glaciers are large masses of ice that move slowly. As they move, they scrape and grind the underlying rock, creating U - shaped valleys and fjords.

Answer:

1. Alfred Wegener believed continents 'drifted' apart due to geological fit (coastline matching), fossil evidence (same fossils on separated continents), rock - formation correlation (similar rocks and mountain ranges on different continents), and paleoclimatic evidence (glacial evidence in non - glacial areas).
2. The theory of plate tectonics was developed in the 1960s by multiple scientists. It combines continental drift and seafloor - spreading concepts and explains the movement of Earth's lithospheric plates.
3. GPS can measure plate motion. GPS receivers on the Earth's surface monitor point positions over time. For example, it shows the North American and Eurasian plates are moving apart at about 2.5 cm/year.
4. Three ways of erosion: water erosion (rivers carving valleys like the Grand Canyon), wind erosion (creating sand dunes in deserts), glacial erosion (creating U - shaped valleys and fjords).