Chapter 29/30 Study Guide Marine invertebrates Archean Is younger than the rock it cuts through Dakota Sandstone Dinosaur footprint 2 half-lives correlation Original remains Fossil evidence Embedded fragments mold Asteroid impacting Earth Replaced remains (2 times) Large space object hitting Earth Permian superposition 50 percent 1. Older rocks contained within newer rocks are called ____________________________ 2. The statement that the oldest layer will be at the bottom in an undisturbed sequence of sedimentary strata is called the Principle of _________________________________ 3. The principle of cross-cutting relationship states that an igneous intrusion is __________________________ 4. Fossils formed when the soft parts of an organism decayed and the hard parts were replaced by minerals are called ___________________________ 5. An example of a trace fossil is ____________________________ 6. A cast can form only after the formation of a(n) _________________________ 7. Petrified wood is a good example of what type of fossil? _________________________ 8. The matching of rock layers from one area to another is called _____________________ 9. Specterium-35 has a half-life of about 10 days. If a sample that originally contained 100 grams of Specterium-35 now contains only 25 grams, the sample has gone through _________________________________________ half-lives. 10. A woolly mammoth found in the permafrost (permanently frozen, icey ground) of Siberia is an example of a(n) _____________________________________ 11. The oldest eon of geologic time is the ______________________ 12. The divisions of the geologic timetable are based upon __________________________ 13. The organisms most affected by the extinctions at the end of the Paleozoic Era were the ___________________________ 14. The site famous for its abundant Jurassic dinosaur remains is known as the _________________________ 15. Approximately what percentage of plant and animal groups do scientists think became extinct at the end of the Mesozoic Era? ___________________________________ 16. During which period would you not expect to find dinosaurs roaming Earth? ________________________ 17. The hypothesis for the cause of dinosaur’s extinction that has the most scientific support links their extinction to ________________________________ 18. Most modern geologists have argued that a global catastrophe may have caused the extinction of the dinosaurs. According to these scientists, what was this catastrophe? ____________________________________ ****There are 12 more questions on the test that are not on this study guide. Those questions require you to read a graph or chart in order to answer the question. *******