Lab 1 - Sedimentary Rocks (ONLINE) - 2024 Spring Earth History Laboratory (GEOL-105L-18)

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Environmental Geology 105L Name: Lab 1: Sedimentary Rocks and Depositional Environments e You will need: Internet Your manual “Chapter 2” provided on OAKS The Lab 1 SedEnv PPT pdf provided on OAKS 0000 Introduction and Fundamentals: See “Chapter 2-sedimentary rocks and environments”, on OAKS to answer the questions in this section. Please note this is not your Marshak lab manual; this lab manual was written “in-house” by Dr. Bobby Boessenecker. 1. Can metamorphic and igneous rocks become sedimentary rocks? 2. Can sedimentary rocks become sedimentary rocks? 3. What is sediment? 4. How do sediments become sedimentary rocks? 5. Briefly explain how each type of sedimentary rock is formed: a. CLASTIC: b. INORGANIC: c. ORGANIC: PART 1: ROCKS: Shale, Siltstone, Conglomerate, Sandstone Use slides 2-7 on the provided Lab 1 SedEnv PPT pdf on OAKS to answer the questions in Part 1. 1. Are these rocks CHEMICAL, ORGANIC, or CLASTIC? 2. Read slide 3. How are sedimentary rocks classified? 3. Observe slides 4 and 5 to put the rocks in order from consisting of the largest to smallest grains (if there are various grain sizes, use the largest grains): Largest Smallest
4. Which sediment do you think becomes each of the following sedimentary rocks? (Use: the sediment terms sand, clay, silt, and gravel for your answers) a. Conglomerate: b. Sandstone: c. Siltstone: d. Clay: Observe slides 5 and 6 (Lab 1 SedEnv PPT pdf on OAKS) to answer questions 5-12. Note that the “Source area” is the rock from which these grains originally eroded. 5. As grains are transported farther from their source do they get BIGGER or SMALLER? 6. As grains are transported farther from their source do they get MORE or LESS rounded (only compare gravel to sand)? 7. Which would take a higher amount of energy to transport, GRAVEL or CLAY? 8. Therefore, smaller grain sizes take MORE or LESS energy to transport. 9. And larger grain sizes take MORE or LESS energy to transport. 10. Which rock do you think would form closest to the source area? 11. Which of these clastic rocks do you think would form farthest from the source area? 12. Put the sediments in order according to the energy needed to transport them. Use the same sediment terms from question 4. HIGH ENERGY LOW ENERGY Slides 5, 6 and 7 describes sorting. Read it to answer questions 13 & 14. 13. Which of the 4 clastic rocks has poorly sorted grains? List all that apply! 14. Which of the 4 clastic rocks has well sorted grains? List all that apply! Read pages 3-5 from “Lab Manual Chapter 2-sedimentary rocks and environments” on OAKS to answer questions 15-20. 15. Areas where eroded sediments are deposited are called: 16. Where would conglomerate likely be formed? Pick one: DEEP OCEAN ALLUVIAL FANS MARSH SAND DUNES 17. Is this (Q#16 answer) a HIGH or LOW energy environment? 18. Where would sandstone likely be formed? Pick one: DEEP OCEAN ALLUVIAL FANS MARSH SAND DUNES
19. Where would shale and siltstone most likely form? Pick two: DEEP OCEAN ALLUVIAL FANS MARSH SAND DUNES 20. Are these (Q#19 answers) HIGH or LOW energy environments? Complete PART 1: ROCKS: Shale, Siltstone, Conglomerate, Sandstone of the table found on pg.5 with the information from this section. In the characteristics column, note anything you learned that would help you identify this sample, for example that it is well sorted. PART 2: ROCKS: Fossiliferous Limestone, Fossil Coral, Coquina, Chalk Use slides 8-14 on the provided Powerpoint PDF to answer the questions in this part. 1. See slide 9. Of what chemical compound are the limestones composed? Hint: same chemical compound as the mineral Calcite. See slide 10 on fossiliferous limestone. Where did the creatures that make up this sample live...in other words, what was their depositional environment (Chp. 2 will help!)? . See the map on slide 11. A sample of fossiliferous limestone was found at location 6B and is found to be 5-10 million years old. Answer the following: a. In what state was this sample found? b. What do you notice about the line showing sea-level 5-10 million years ago? c. How do scientists know that sea-level used to be all the way up near Columbia, SC? See slide 12 on fossil coral and read about the conditions they need to thrive. If this sample was found in northern Texas and is dated to be 3 million years old. What does this tell you about te environment of northern Texas 3 million years ago? See slide 13 on coquina (and Chp.2) and answer the following: a. What is the energy level where this sample was formed, high or low? b. What is the depositional environment? See slide 14 on chalk and answer the following: a. Do you think chalk forms in a high or low energy environment? (Hint: remember the grain size is tiny!) b. Do you think this chalk forms nearshore or in the deep ocean? (Hint: think of where it would be more quiet for small grains to settle out!) c. See the map again on slide 11. Sample 6D is a location where 100-million-year old chalk was found. Was sea level higher or lower at this location 100 million years ago? Complete_PART 2: ROCKS: Fossiliferous Limestone, Fossil Coral, Coquina, Chalk of the table found on page 5 of this lab with the information from this section.
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PART 3: ROCKS: Fossiliferous Shale, Peat, Coal Use slides 15-17 on the provided Powerpoint to answer the questions in this part. 1. Fossiliferous shale is simply shale that has fossils preserved in it. These fossils can be marine (ex. bivalves), or can be leaves and other plant matter. Recall from learning about shale in part 1, is this rock formed in a HIGH or LOW energy environment? 2. Therefore, which of the following is an environment where you think fossiliferous shale with plant matter would be preserved? (CHOOSE ONE!) DEEP OCEAN SWAMP ALLUVIAL FAN RIVER 3. See the image on slide 16, showing how shale (likely with preserved plant fossils) becomes peat, and then coal. Answer the following by observing this image: a. What is formed first, PEAT or COAL? b. What takes more pressure to form, PEAT or COAL? 4. Slide 17 shows pictures of each of these rocks. Which do you think is the most compacted, PEAT or COAL? 5. Look back to the map on slide 11. Shale was deposited at location 7A and dated to be 390 million years old. What does this tell you about #he climate of this location 390 million years ago? (Hint: in what type of climate are present-day swamps?) Complete PART 3: ROCKS: Fossiliferous Shale, Peat, Coal of the table on pg.5 of this lab with the information from this section. PART 4: ROCKS: Halite, Gypsum, Stalactite/Stalagmite Use slides 18-20 on the provided Powerpoint to answer the questions in this part. 1. Slide 19 shows two evaporites, Halite and Gypsum. See pg.7 of the pdf “Chapter 2-Sedimentary rocks and environments™ and answer the following: a. How do evaporites form, and in what type of climate? b. Where do evaporites form (what is their depositional environment)? c. For what is Halite used? d. For what is Gypsum used? 2. Slide 20 shows two speleothems, stalactites and stalagmites. See pg.7 of the pdf “Chapter 2-Sedimentary rocks and environments” and answer the following: a. How do speleothems form? b. Where do speleothems form (what is their depositional environment)?
c. Groundwater flowing through what rock can dissolve and redeposit calcium carbonate (CaCO3)? d. What, then, is the difference between these limestones and the ones you looked at in Part 2? 3. Look back to slide 11. Gypsum and Halite are found present-day, on the surface, at locations 8A&B. These rocks needed restrictive basins to form, with no outlet for water besides evaporation. Answer the following: a. What would the climate have been like to form these rocks at this location: ARID/DRY or HUMID/WET? b. Inwhat state are these rocks found? Complete PART 4: ROCKS: Halite, Gypsum, Stalactite/Stalagmite of the table below with the information from this section. Part/Station 1-Clastic Sed Rocks Characteristics Depositional Environment Conglomerate Sandstone Siltstone Shale Part/Station 2- Organic Sed Rocks-Limestones Fossiliferous Limestone Chalk Coquina Fossil coral Part/Station 3- Organic Sed Rocks- non-Limestones Fossiliferous Shale Peat Coal Part/Station 4- Inorganic Sed Rocks Halite Gypsum Stalactite
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Environmental Geology 105L Name: Sedimentary Structures and Depositional Environments e You will need: o Internet o “Chapter 2-Sedimentary Rocks and Environments” provided on OAKS o The SLIDES pdf provided on OAKS INTRODUCTION: See “Sedimentary Structures” on page 7 in “Chapter 2-Sedimentary Rocks and Environments.” 1. In your own words, what are sedimentary structures? 2. What is the RELATIONSHIP (DIFFERENCE) between Sedimentary Rocks and Sedimentary Structures? 3. Why do you think geologists are interested in studying sedimentary structures; what can they tell us? PART 1: Sedimentary Structure: Graded Bedding See “Graded Bedding” on page 8 of “Chapter 2-Sedimentary Rocks and Environments,” which describes how graded beds are formed from debris flows changing their velocity. 1. As the debris flow first slows down, what size grains are deposited, the LARGEST OR SMALLEST? See Slide 2 which illustrates how a graded bed forms. 2. Would you describe the flow as a HIGH OR LOW energy event? 3. Would you describe the terrain where the debris flow takes place as FLAT OR STEEP? 4. As the flow goes down a steep slope it picks up sediments of various grain sizes. Would the sediment in the flow therefore be WELL-SORTED OR POORLY-SORTED? 5. When the debris flow stops, a graded bed is deposited. Is the graded bed deposited in a STEEPER OR FLATTER area, compared to where the actual debris flow took place? See Slide 3, showing a graded bed as preserved in the geologic record. Note the various grain sizes. 6. If this source rock eroded and you found an individual rock from it, what would it most likely be: SANDSTONE SHALE SILTSTONE CONGLOMERATE
7. Besides the ocean environment, as shown in Slide 2, what are some depositional environments (and related events in that environment) where graded beds would form? (Chapter 2 will help) List all that apply! VOLCANO(Lahar) BASE OF A MOUNTAIN(Landslide) RIVER(Flash flood) 8. Fill in the table in the on-line portion on page 5 of this lab with the information from this section. a. You should be able to fill in the “Depositional Environments” column. b. The “Notes” column should contain any helpful information for you to better understand these structures, or to help you identify these structures in the future. PART 2: Sedimentary Structure: Cross Bedding See “Cross-Bedding” on page 8 of “Chapter 2-Sedimentary Rocks and Environments. 1. In which rock is cross bedding typically preserved? SANDSTONE SHALE SILTSTONE CONGLOMERATE 2. How do cross beds form, from WIND OR WATER OR BOTH WIND AND WATER? 3. Where are cross beds typically formed? List all that apply! DESERT DUNES LAKE VOLCANO(Lahar) BEACH DUNES See slide 4 for examples of cross bedding as preserved in the rock record. The photo on the left was taken in Utah, and these dunes formed ~200 million years ago. 4. What does this tell you about Utah’s environment 200 million years ago compared to today? 5. Fill in the table in the on-line portion of this lab on page 5 with the information from this section. See #8 in Part 1 for specific instructions. PART 3: Sedimentary Structure: Ripple Marks See Slide 5, and “Ripples” on page 9 in “Chapter 2-Sedimentary Rocks and Environments™ for information on how ripples form, to answer the following questions: 1. For asymmetrical ripple marks to form, is the water going in ONE DIRECTION OR BACK AND FORTH? 2. For symmetrical ripple marks to form, is the water going in ONE DIRECTION OR BACK AND FORTH? 3. Asymmetrical ripples form from: WATER OR WIND and WATER 4. Symmetrical ripples form from: WATER OR WIND and WATER 5. See Slide 6, showing the preservation of asymmetrical ripples in the geologic record. 6. See Slide 7, showing the preservation of symmetrical ripples in the geologic record.
7. In which depositional environment(s) do you think asymmetrical ripples would form? (Hint: is the swater/wind moving back and forth or in one direction?) List all that apply! DUNES RIVER ESTUARY/MARSH(from tide) BEACH OCEAN(from current) 8. In which depositional environment(s) do you think symmetrical ripples would form? (Hint: is the swater/wind moving back and forth or in one direction?) List all that apply! DUNES RIVER ESTUARY/MARSH(from tide) BEACH OCEAN(from current) 9. Fill in the table in the on-line portion of this lab on pg.5 with the information from this section. See #8 in Part 1 for specific instructions. PART 4: Sedimentary Structure: Mudcracks See “Mudcracks” on page 9 in “Chapter 2-Sedimentary Rocks and Environments™. 1. How do mudcracks form? 2. Of the clastic rocks you learned about last week, in which of the following could mudcracks form? List all that apply! SANDSTONE SHALE SILTSTONE CONGLOMERATE See Slide 8 showing mudcracks. 3. If mudcracks are found in the geologic record, what do they indicate about the paleo-environment in that location? 4. Fill in the table in the on-line portion of this lab on pg.5 with the information from this section. See #8 in Part 1 for specific instructions. PART 5: Sedimentary Structure: Varves See Slide 9 on varve formation and “Varves” on pages 9-10 in “Chapter 2-Sedimentary Rocks and Environments” to answer the following: 1. How do varves form? 2. In which of the following environments would you expect to find varves? List all that apply! LAKES FIORDS VOLCANOES RIVERS 3. In which of the following clastic rocks can varves form? List all that apply! SANDSTONE SHALE SILTSTONE CONGLOMERATE
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See Slide 10, showing varves as preserved in the rock record in present-day Colorado, Utah, and ‘Wyoming. a. These varves are approximately 60 million years old. What does this tell you about the environment in these locations approximately 60 million years ago? b. What was the energy of this environment—HIGH OR LOW? Fill in the table in the on-line portion of this lab on pg.5 with the information from this section. See #8 in Part 1 for specific instructions. PART 6: Sedimentary Structure (Erosional Surface): Striations See “Striations” on page 10 in “Chapter 2-Sedimentary Rocks and Environments”. 1. Striations on rocks are caused by erosion from glaciers. How do glaciers cause these linear scratches on the surface of rocks? See Slide 11 which shows glacial striations in Central Park, New York City, NY. 2. 3. Does NYC currently have glaciers? YES NO The striations in Central Park were formed ~15,000 years ago. Was NYC WARMER or COOLER than present day? ‘What has happened to climate since then? INCREASED DECREASED Fill in the table in the on-line portion of this lab on pg.5 with the information from this section. See #8 in Part 1 for specific instructions.
Depositional Environment Notes (ex. rock found in etc.) Part/Station 1- Graded Bedding Part/Station 2- Cross Bedding Part/Station 3- Ripple Marks -Asymmetrical -Symmetrical Part/Station 3- Mudcracks Part/Station 4- Varves Part/Station 6- Striations