Geology Quiz Answers Chapter 9

Chapter 9: ● Rocks contain evidence that which of the following processes occurred throughout Earth's history? ○ The seas advanced and retreated. ○ Mountains were uplifted and eroded. ○ Different types of creatures lived and became extinct. ● Relative dating ______ to determine the order in which geologic events occurred. ○ uses geologic principles ○ uses common sense ● When geologists assign actual numbers to the age of a rock unit, they determine the ______ age. ○ Isotopic or numeric ● Which of the following are principles of relative dating? ○ Cross-cutting relations ○ Superposition ○ Original horizontality ● Which principle can be used by a geologist to determine that the rocks shown in the photograph have not been deformed since they were deposited? ○ ○ Original horizontality ● Rocks around the world contain evidence that _____ have advanced and retreated, and _______ have been uplifted and eroded. ○ Oceans ○ Mountains ● Geologists can tell that folded sedimentary rocks have been deformed by the principle of ___________. ○ Original horizontality ● Relative dating is concerned with the _______ in which geologic units were formed, rather than with their age. ○ Order or sequence ● Which principle is used to determine the age of rocks by ordering them from oldest on the bottom to the youngest on the top? ○ Superposition ● Isotopic dating is accomplished by assigning ages in years to rocks using ______ dating methods. ○ Analytical ● When an igneous dike cuts across sedimentary strata, the principle of ______ relations can be used to determine the relative age. ○ Crosscutting ● Match the principle of relative dating with its definition. ○ Superposition ■ The oldest rock is on the bottom ○ Crosscutting relations ■ The fault is younger than the rocks it cuts across ○ Original horizontality ■ Sediments and volcanic units are usually deposited in flat-lying layers. ○ Inclusions ■ Rocks may incorporate older pieces of rock ○ Contact effects ■ A baked zone forms next to a dike during intrusion. ● ______ may form as erosion by a river further downcuts and widens a canyon, making a more intricate canyon formation. ○ Tributaries ● The principle of original horizontality means that flat-lying sedimentary rocks have not been ______. ○ Deformed ● Buried erosion surfaces that represent large intervals of time are called ○ Unconformities ● Which principle of relative dating can be used at Siccar Point in Scotland to determine that the rocks below the unconformity were tilted to vertical before erosion occurred? ○ Original horizontality ● Order the events that form an angular unconformity from the first event at the top to the last event at the bottom. ○ Rocks are deposited horizontally. ○ Rocks are folded. ○ Uplift occurs, and folded rocks are eroded. ○ Horizontal rocks are deposited over eroded tilt beds. ● The principle of _____ tells geologists that the oldest rock layer in the diagram is on the bottom; therefore, it was deposited first. ○ Superposition ● Isotopic dating allows scientists to assign numeric ages to rock using the natural _____ decay to certain isotopes. ○ Radioactive ● Which principle can be used to determine the relative age of an igneous intrusion called a dike? ○ Cross-cutting relations ■ Principle 4 states that younger rocks or features can cut across any older rock or feature. ● An isotope refers to any element that has the same number of protons but a different number of ○ Neutrons ● Subsidiary drainages on a river are known as ______. ○ Tributaries ● _____ are evidence of ancient life in sedimentary rocks. ○ Fossils ■ Dendrites are branching mineral growths found between sedimentary layers that are commonly mistaken for fossils. ■ Concretions are spherical features that grow in sediment during cementation and are commonly mistaken for fossils. ● The type of unconformity shown in this diagram is a(n) ______. ○ ○ Angular unconformity ■ The underlying rocks were tilted before the formation of the erosion surface, making the unconformity an angular unconformity. ● True or false: Fossils can include traces and imprints of plants and animals as well as their remains. ● ● ● ● ● ● ● ● ○ True ■ Fossils are not just bones, but can include any physical indication of life. For example, dinosaur footprints are considered trace fossils. Order the four chapters in Earth history from youngest at the top to oldest at the bottom. ○ Cenozoic ○ Mesozoic ○ Paleozoic ○ Precambrian Isotopes are different forms of an element that have different ______. ○ atomic weights ○ numbers of neutrons Geologists use ______ to document evolution in the rock record. ○ Fossils When a geologist attempts to match up two different sections of rock according to time, he or she is ______ the rocks. ○ Correlating Which of the following are important about fossils in the rock record? ○ They can be used to date rocks. ○ They are evidence of ancient life. ○ They document the evolution of life. Match the resulting fossil with its method of preservation. ○ Petrified wood ■ Organic matter replaced by silica or pyrite ○ Insect in amber ■ Organic matter trapped in tree sap ○ Dinosaur bones ■ Hard parts buried and preserved ○ Fish with fins and scales ■ Impressions on a lake bed ○ Fossil fern ■ Thin films of carbon on a rock surface The geologic timescale details and divides geologic time based upon ____. ○ fossil data Match each geologic era with its meaning in the fossil record ○ Cenozoic ■ Recent life ○ Mesozoic ■ Middle life ○ Paleozoic ■ Ancient life ● Which of the following types of data could be used by geologists to estimate the age of past Earth events? ○ Tree rings ○ Ice cores ○ Lake varves ● The fossil record has been used to document observed changes in organisms over time; in other words, it has been used to study ______. ○ Evolution ● Trilobites first appeared on Earth during the ______ Period, when a so-called _____ of life (rapid evolutionary change) introduced many new species in a short time frame. ○ Cambrian ○ Explosion ● Dinosaurs are the best-known creatures of the ______ Era. ○ Mesozoic ● There were two types of dinosaur: those such as Tyrannosaurus rex that had hip structures similar to ________ and those such as Stegosaurus that had hip structures similar to ___. ○ Lizards ○ Birds ● Which of the following statements are true regarding the geologic timescale? ○ It was first created using relative dating and correlation. ○ It is based on data from fossils. ● The first humans appeared before 300,000 years ago in the _______ Era. ○ Cenozoic ● The oldest _____ cores in Antarctica have over 100,000 annual layers. ○ Ice ● What events occurred at the beginning of the Cambrian Period, approximately 542 million years ago? ○ Evolution of more organisms with hard parts ○ Rapid evolutionary change ○ Explosion in the amount of diversity of life ● The Mesozoic Era is known as the age of the ______, after the best-known creatures of this age. ○ Dinosaurs ● The Cenozoic Era is called the age of ______ because of their abundance and diversity during this time. ○ Mammals