Lesson 7 Homework Questions Instructions: Answer each of the following questions. Your responses can be short answer, short essay, or a list -- just be sure to answer each question completely. Ch. 13: 1. What are the characteristics of Earth’s lithosphere and asthenosphere? The region that lies beneath the lithosphere is termed as asthenosphere. The rocks in the lithosphere region are rigid and cannot flow whereas in asthenosphere they are plastic and can flow under deformation. 2. Which family of minerals is most abundant in Earth’s crust and what is the common chemical starting point of these minerals? Silicate Minerals. The roughly 1,000 silicate minerals make up over 90% of Earth's crust. Silicates are by far the largest mineral group. silicia 3. How are igneous rocks classified according to their composition and texture? Igneous rocks can be classified by compo- sition based on the major minerals in the rocks. Light-colored rocks have granitic com- positions. Dark-colored rocks have basaltic compositions. Dark-colored rocks that contain only olivine and pyroxene are ultramafic rocks. 4. In what ways are granite and basalt different?Granitic rocks containmostly quartz and feldspar and thus are light-colored.Basaltic rocks are rich in iron and thus are dark-colored and more dense. 5. Describe and explain the formation of detrital-, chemical-, and organic sedimentary rocks. Give one example of each.Detrital (sandstone) form from the accumulated fragments of weathered rockChemical (limestone) develop from the precipitation of dissolved compounds (such as calcium carbonate)Organic (bituminous coal) consists of compacted dead plant materail 6. What is foliation, and under what conditions are metamorphic rocks likely to be foliated? 7. Is oceanic lithosphere or continental lithosphere denser? Oceanic lithosphere is typically about 50–140 km thick(but beneath the mid-ocean ridges is no thicker than the crust), while continental lithosphere has a range in thickness from about 40 km to perhaps 280 km; the upper ~30 to ~50 km of typical continental lithosphere is crust. 8. What is meant by the “structure” of a landform? Structure consists of the materials and their respective arrangement that a landform is made up. Like a mountain is made of granite, sandstone, copper or some other material and this is the material arranged in horizontal, layers in these structures .
- Winter '11