Chapter 2 1-What is the evidence for plate tectonics? Fit of continents, fossils

Question

Chapter 2

1-What is the evidence for plate tectonics? Fit of continents, fossils, structural similarities, rock types, paleomagnetism, hot spots, etc.

2-Know and understand the three types of plate boundaries. What is going on in geologic terms, lithospheric types, and geologic features associated with each type. Where is lithosphere created? Destroyed? Most complicated is convergent, know about O-O, O-C, and C-C collisions.

3-Know the boundaries of the North American Plate. What Plates border it? Is the east coast of North America a plate boundary? Where is the boundary?

4How do the earthquakes associated with each plate boundary differ (Deep versus shallow, large versus small, etc)?

6-How fast are the plates moving? Know the range of motion.

7-What are hot spots and how do they explain plate movement?

8-What are the three forces the move plates? Slab pull, ridge push, convection.

9-What is the Curie Point and why is it important?

Chapter 3

1-Know the definition of a mineral.

2-What is a rock?

3-What is glass and why is it not a mineral?

4-Know and be able to describe the three main mineral forming molecular bond types.

5-Explain how substitution works in mineral structures?

6-What is a polymorph?

7-Know and describe the following mineral physical properties: crystal form, luster, color, streak, hardness, cleavage, fracture, specific gravity, special properties. (for lab use)

8-Have a rough idea (main rock forming minerals) of the order of minerals on the Mohs scale of hardness.

Explanation / Answer

1.

The Earth has a layered structure, including the core, mantle and crust. The crust and upper mantle are cracked into large pieces called tectonic plates. These plates move slowly, but can cause earthquakes and volcanoes where they meet.

Evidence

The shapes of many continents are such that they look like they are separated pieces of a jig-saw puzzle. For example, look in the adjacent map at the shape of the east coast of North and South Americal relative to the shape of the west coast of Africa and Europe.
Many fossil comparisons along the edges of continents that look like they fit together suggest species similarities that would only make sense if the two continents were joined at some point in the past.
There is a large amount of seismic, volcanic, and geothermal activity along the conjectured plate boundaries. This is shown clearly below in the figure labeled "Crustal plate boundaries" where the epicenters of earthquakes above Richter magnitude 5.0 are plotted for a 10-year period. The concentration is striking, and indeed this plot serves to define the plate boundaries extremely well. Here is a clickable map of current volcanic activity on Earth.
There are ridges, such as the Mid-Atlantic Ridge (see figures above and below) where plates are separating that are produced by lava welling up from between the plates as they pull apart. Likewise, there are mountain ranges being formed where plates are pushing against each other (e.g., the Himalayas, which are still growing).
Plate tectonic motion, which may be only centimeters per century, is now being studied by careful laser ranging techniques that are capable of detecting such small motions.

Plate tectonics

The Earth's crust and upper part of the mantle are broken into large pieces called tectonic plates. These are constantly moving at a few centimetres each year. Although this doesn't sound like very much, over millions of years the movement allows whole continents to shift thousands of kilometres apart. This process is called continental drift.
The plates move because of convection currents in the Earth's mantle. These are driven by the heat produced by the decay of radioactive elements and heat left over from the formation of the Earth.
Where tectonic plates meet, the Earth's crust becomes unstable as the plates push against each other, or ride under or over each other. Earthquakes and volcanic eruptions happen at the boundaries between plates, and the crust may

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.