1. What is the “age” of the Grand Canyon of the Colorado River? Kip Ault, Ph.D. Lewis & Clark College

4. Laurasia and Gondwana North America Pangea Rodinia

5. The Wilson Cycle

6. Grand Canyon

11. 250-40 Million Years Ago “Mezozoic and Cenozoic” Age of Reptiles to Primitive Mammals: Bryce Canyon Dinosaur Monument Glen Canyon Zion Canyon

13. What happened to the “Andes and Amazon” landscape in Arizona?

17. 299 to 251 MYA “Permian” 90% of marine species extinct by end Kaibab Limestone Cliffs: Tropical tidal flats Toroweap Layers: Warm shallow seas Coconino Sandstone Cliffs:Coastal dunes Hermit Shales (slope): River floodplains

20. 318 to 299 MYA “Pennsylvanian” Supai Group: Esplanade Sandstone Cliffs Gondwana Collides with Laurasia to form Supercontinent Pangea Ice Ages raise and lower seas

22. Redwall Formation 400 feet thick 416 to 318 Million Years Ago “Mississippian” Carbonate Seas deposit limestone Cliffs and caves from the Tetons to Tucson!

29. 525 to 318 MYA “Cambrian” Seas expanding calmly onto land Muav Limestone Bright Angel Shale Tapeats Sandstone

35. 1.25 to.75 Billion Years Ago “Late Proterozoic” Rodinia rifts apart Grand Canyon Supergroup: Chuar-Cardenas-Nankoweap- Unkar 12,000 feet thick!

44. 1.75 Billion Years Ago “Early Proterozoic” Island Arcs added to North American Craton Once 15 miles below the surface of the earth! Vishnu Schist and Zoroaster Granite

47. The Great Unconformity 740-1255 mya 525 mya 1750 mya Angular Unconformity 525 mya

49. The Great Nonconformity

55. Atlantic rifting Pangea Grand Canyon carving Pre and Post Rodinia

57. Focus Question ThinkingDoing Concepts Principles Events and Objects Vee Diagram of Inquiry from D. B. Gowin Records Claims (Prior Knowledge)(New Knowledge))

58. When did the Colorado River begin to carve the Grand Canyon? (Focus Question)

59. How did the San Andreas fault help the Colorado River leave the Colorado Plateau?

60. Implications of the Miocene(?) Crooked Ridge River of Northern Arizona for the Evolution of the Colorado River and Grand Canyon Ivo Lucchitta (New Knowledge Claims)

61. Origin and Evolution of the Colorado River System Karl E. Karlstrom (New Knowledge Claims)

62. The mystery of the pre–Grand Canyon Colorado River—Results from the Muddy Creek Formation Joel L. Pederson (New Knowledge Claims)

63. Age of the Grand Canyon: 80 million or 6 millions years? 80 mya ago the Cretaceous seas withdrew. Rivers drained to the Northeast for 50 million years. Laramide orogeny uplifted the Colorado Plateau— North American crumpled and the Farallon Plate subducted shallowly from 70 to 40 mya. Rivers “disappear” from view on the Colorado Plateau between 30 and 16 mya (Principles and Prior Knowledge)

65. Basins formed to the West (Muddy Creek Formation) and to the East (Bidahochi Formation) 16 mya the Mogollan Highlands to the Southwest begin to rift apart and collapse. At this time the spreading zone in the Pacific collided with the North American plate to create the San Andreas fault. Instead of compressing, the North American plate began to pull apart. The Basin and Range Province forms to the West and Southwest of the Colorado Plateau. (Claims from prior inquiries)

66. How and when did the Colorado River find its way through the Colorado Plateau and to the Sea of Cortez? (Focus Question restated)

67. How and when did the Colorado River find its way through the Colorado Plateau and to the Sea of Cortez? Or, how and when did the sections of the Colorado River above and below the Grand Canyon join together? (Additional Focus Question)

68. Headward erosion and stream capture of the Little Colorado? Reversal of drainage in Marble Canyon? Catastrophic spillover of lakes? (Competing hypotheses with key concepts)

69. Where did the Colorado River flow before 6 mya? To the Northwest after going around the Kaibab Plateau? To the Southwest through Peachtree Canyon? To the Southeast down the Little Colorado to the Rio Grande and the Gulf of Mexico? Or underground and emerge to deposit the Hulapai Limestone? (Competing claims dependent upon Records of Events)

71. 16 mya: Muddy Creek Formation at the mouth of the Grand Canyon has no sediments from up the Colorado drainage.. Interestingly, above the Muddy Creek lies the Hualapai Limestone. (Objects and Events; Records of Events)

72. The distribution of sedimentary rocks and the timing of tectonic and climatic events are the keys to solving the puzzle. (Objects of Interest—key records) (Principle: order events in time on different scales)

75. Focus Question ThinkingDoing Concepts Principles Events and Objects Vee Diagram of Inquiry from D. B. Gowin Records Claims (Prior Knowledge)(New Knowledge))