ASBOG Practice Exam

Paleontological data helps geologists classify strata using which of the following?

1. Geological maps, index fossils, regional models

2. Index fossils, collections of fossils

3. Radiometric dating, sedimentary structure, tectonic history

4. Fossil assemblages, mineral continuity, plate tectonics

The correct answer is: Index fossils, collections of fossils

Paleontological data is primarily utilized in geology to classify strata through the use of index fossils and collections of fossils. Index fossils are fossils of organisms that were widely distributed but only existed for a relatively short period of geologic time. This characteristic makes them extremely useful for correlating the age of rock layers across different geographical locations. Collections of fossils allow geologists to compare and contrast the assemblages found within different strata. By assessing the various collections from distinct layers, geologists can determine the relative ages of the strata and draw conclusions about the environment in which those layers were deposited. This correlation of fossil evidence aids significantly in understanding the chronological sequence of geological events and provides a foundation for constructing geological time scales. The alternative choices involve elements such as geological maps and regional models, which do not directly pertain to paleontological data in the same specific way, or radiometric dating and tectonic history, which focus on different aspects of geology and do not primarily derive from fossil data. While these might contribute to geological understanding, they do not utilize paleontological evidence in the classification of strata as directly as the concept stemming from index fossils and fossil collections.