Geology Homework Questions chs 7-9

Geology Homework Questions (CHAPTERS 7-9) Chapter 7: 1. Which of these is most likely to be a biochemical sedimentary rock? - Limestone 2. Which way was the current (either wind or water) moving during deposition of this section of rocks? - toward the right 3. Which of the following can we understand by studying sedimentary rocks? - past events, such as landslides and earthquakes - how environments shifted in location through time - migration of deserts and advances of the sea - past changes in climate 4. A sandstone with a pinkish or reddish color that is the result of oxidation of iron-bearing minerals indicates the sand was: - deposited on land and exposed to air. 5. Which of the following situations would result in angular clasts? - steep slopes in a mountain 6. The natural cements that hold clasts together precipitate in the empty pore spaces after compaction. Those precipitates come from - water containing dissolved materials. 7. Most of the exposed surface of Earth is covered with - sediment and sedimentary rocks. 8. A sandstone containing mostly sand but mixed with rounded pebbles and pieces of shells indicates deposition: - by waves at the beach. 9. Melting glaciers tend to deposit most of the sediment they carry and create - at their terminus (end). 10. Which of the following environments is NOT a setting in which limestone forms? - All these are environments in which limestone forms. - (some lakes, coral reefs, deposition of calcite near springs, accumulation of the remains of microscopic organisms)

11. Clastic sedimentary rocks are classified primarily on the basis of - sediment size. 12. The two main processes by which sediment is produced are - physical and chemical weathering. 13. What type of product is being produced from material in these quarries? - Cement 14. The deep-sea floor is characterized by sediment dominated by - fine dust and the remains of single-celled organisms. 15. Sedimentary environments on land differ because of variations in - local geology. - amount of water. - topography. 16. Which environment is least likely to deposit siltstone or shale? - channel of a braided river 17. The advance of the sea across a region is known as a: - transgression. 18. Which of these is not correct in pairing how a specific mineral reacts to weathering? - All of these choices are correct. - (Quartz transforms into sand, Feldspar transforms into clay minerals, Mafic minerals transform into iron oxides.) 19. Streams deposit sediments in a __________ when they reach an ocean or lake. - Delta 20. What is the main difference between conglomerate and breccia? - the shape of the clasts 21. Bedding in sedimentary rocks is defined by: - resistance to erosion. - thickness. - color. - sediment size. 22. What is a sedimentary facies? - a sediment or sedimentary rock deposited in a specific environment 23. Which of the following processes produce sedimentary clasts? - fracturing of bedrock that results in angular pieces - decomposition of granite into quartz grains and clay - breaking of round cobbles as they are transported - scouring and abrasion of bedrock along rivers 24. Floodplains are built of - mud and sand deposited by floodwaters. 25. Which of the following is NOT involved in turning some sediment into sedimentary rock? - Metamorphism - (correct answers: cementation, burial, compaction) 26. Large, angular clasts are most likely at

- mountains at A and glaciers at B. 27. Which of the following does NOT correctly match a rock with a possible environment in which that rock forms? - coal – deep-sea organic-rich black shale - (correct answers: salt – evaporation of water, gypsum – evaporation of water, chert – mixing of seawater and groundwater, chert – accumulation of tiny silica-rich creatures) 28. What type of rock would you form in this plant-rich swamp? - Coal 29. Geologists use characteristics such as bedding, mudcracks, and color preserved in sedimentary rocks to determine: - the environment in which the rocks were deposited. 30. Which of the following times indicates a regression? - from unit 5 to unit 6 31. What is the best explanation for the shape of these clasts?

- They have been transported a significant distance. 32. What setting was this sedimentary rock deposited in? - a muddy place that sometimes dried out 33. Which of the following is the most used sedimentary resource? - sand and gravel 34. In this section, a lower gray rock is successively overlain by beach sandstone, lagoon mudstone, and limestone. What is the best interpretation of what was going on? - The area was experiencing a transgression. 35. Sorting describes

- the size range of clasts in sediment. 36. Which of the following processes is NOT considered to be chemical weathering? - thermal expansion 37. Which of the following sites would contain the finest grained sedimentary deposits? - Lake at E 38. Sedimentary facies shift toward the sea as the sea moves out during a: - regression. 39. What typically happens to the size, shape, and sorting of clasts as they are transported from steep mountains toward more gentle settings? - The clasts become more rounded. 40. Sedimentary clasts are - loose fragments of rocks and minerals. 41. What do fossils pr eserved in the rock record tell us about Earth’s history? - that environments changed and the organisms that lived in them either evolved or went extinct 42. Which of the following environments would most likely consist of sand and/or rounded cobbles? - Beach at A 43. What type of rock would you form in this coral reef?