Lab 3 SES 123

Module 3 Worksheets 91 Name____________________________________ MODULE 3 Worksheet 3A. Using the principles of relative dating, determine the sequence of events that occurred to form the rock arrangement shown in the cross section in Figure 3-4 . List the events from oldest at the bottom of the list to youngest at the top of the list. Sequence of Events (oldest at bottom of list; youngest at top of list) Jus tify Your Chosen Sequence By Describing Each Unit’s Relationship To The Other Units Worksheet 3B. Answer the following questions about the animations and photographs. Examine the animation of the seas moving in and out. If you found a place where a marine mud layer overlies a beach sandstone, do you think that sea level was rising or dropping (transgressing or regressing)? In the Hance Rapids photograph, what is the oldest rock unit and why? In the Death Valley photograph, which rock unit is younger, the tilted gray layers or the upper layer with the angular clasts? Give at least two reasons why. I E H G J D B A K L C I is lower than H H is lower F F is lower than E E Is the last layer before the seperation Crosscutting Relationship J is the development of the unconformity. D is the oldest and bottom most layer of the top B is above D A sits above B Intrusion of magma Erosion that cut the canyon River Gravels F The sea-level was dropping. Lower Siltstone and shale The tilted layer is older because it is sitting lower than the upper layer and it is below the unconformity.

Module 3 Worksheets 92 Worksheet 3C. In the space below , summarize the geologic history of Painted Canyon. The main geologic events are listed below on the right (letter A, B, C, …). Reconstruct the sequence of these events, from oldest (first event) to youngest (last event), by considering the following: 1. For each rock sample your team identified in previous modules, observe its location (where it was collected) and its rock type. 2. Analyze the computer images of Painted Canyon, noting the sequence of the rock layers and the cross- cutting relations of faults and igneous intrusions (granite pluton, dark dike, and pegmatite dikes) Once you have determined the sequence of events, write the letter of the events in their proper order ( oldest at the bottom of the list to youngest at the top of the list) in the number below on the left. Last Event (most recent) 16. ____ 15. ____ 14. ____ 13. ____ 12. ____ 11. ____ 10. ____ 9. ____ 8. ____ 7. ____ 6. ____ 5. ____ 4. ____ 3. ____ 2. ____ 1. ____ First Event (oldest) A. Emplacement of igneous dike B. Deposition of mudrock as seas came in (transgression) C. Eruption that formed rhyolite D. Deposition of limestone and formation of chert in clear water E. Pyroclastic eruption that formed volcanic tuff F. Uplift and erosion of metamorphic rocks (formation of unconformity) G. Deposition of sandstone as sea moves in (transgression) H. Erosion by stream to form the canyon itself I. Metamorphism of the basement rocks J. Offset of units along a fault K. Emplacement of granite pluton (This unit reaches 500 feet in elevation and it crosscuts, bakes, and therefore post-dates all units below, including the tuff layer. Whether the granite post-dates the overlying rhyolite and basalt is unknown). L. Deposition/formation of rocks that would later be metamorphosed to form the basement. M. Deposition of breccia N. Deposition of conglomerate O. Eruption of lava flows that formed basalt P. Formation of very coarsely crystalline granite (called pegmatite ) dikes (light-colored dikes) in metamorphic rocks A H J L P F D G B E C I N M O K