SOLVED

71) An unconformity in which the strata on either side are essentially parallel is termed a(n) ________. Critical thinking and discussion questions. Use complete sentences, correct spelling, and the information presented in Chapter 18 to answer the questions below. 72) Compare and contrast relative age dating with radiometric age dating. What is a limitation (if any) of each? 73) In a given area where you have little knowledge of the local geology (rocks types, fossils, etc.), what type of unconformity would be the most difficult to recognize in an exposed sequence of rocks? Why? 74) You are asked to interpret the geologic history of a county in California where the geology is quite complex. Aside from visiting various sites in the county for observing geologic sites firsthand, you are permitted to request five different pieces of information or data to aid in your interpretation. List the five that you would choose and explain why each is important for your study. 75) On the blank provided beside each geologic cross section below, write the name of the specific type of unconformity that is labeled with an arrow. The v-pattern indicates igneous rocks. All other patterns are different types of sedimentary rocks. (a) _____________________________ (b) _____________________________ (c) _______________________________ 76) In the chart of radioactive decay shown below, how many half-lives have elapsed by time? (a) ________ How many half-lives have elapsed by time? (b) ________ 77) Examine the geologic cross section below. Which feature is the youngest? (a) ________ Which feature is the oldest? (b) ________ 78) Examine the illustration below (a cross section through the Earth as you might observe on the wall of a quarry or a road cut). Give two reasons why the granite must be older than the sedimentary layers.