Lab 11

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Clovis Commuity College *

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Geology

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Dec 6, 2023

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Geology Name_____________________ Sediment and Sedimentary Structures lab report Write your responses in a color other than black or red Part 1: Grain size and graded bedding, an experiment 1. Sketch a picture of how your dirt/sand/soil looked when you mixed it, before adding water. 2. Sketch how the mixture looked after water was added and the soil was agitated. 3. What differences were there in how the mixture looked, before and after adding water? Before the water, it was dry, loose, unorganized, and kind of dusty/hard to see, and after adding water it was clumped up, smooth, and stuck together in a layered and ordered fashion. 4. Assuming the sample in Figure 2 has normal graded bedding (as opposed to inverse graded beds), which side of it was toward the top at the time of deposition, A or B?

Geology Name_____________________ Sediment and Sedimentary Structures lab report B. Part 2: Sediment transport in moving water 1. In the delta video, what color of particles are transported the furthest, and what color particles are deposited closest to shore? This flow separates all four colors out from each other. The black particles traveled the furthest, and the yellow stayed closest to shore. 2. In the ripple video, what color of particles forms the crests of the ripples? What color washes down into the troughs? Which colors are left on shore and don't end up forming part of the ripples? White makes the crest, black washes down the troughs, red and yellow form on the shore. 3. Based on the previous questions, you should now be able to answer this: What are the relative sizes of the red, yellow, white, and black particles in the artificial sediment used on these stream tables? Put them in order from smallest to largest. (It's the same in both videos.) Red, Black, White, Yellow. Part 3: Grain size in soils 1. Observe the test tubes in Figure 10 . Estimate the percentage of each layer. Record the data for each sample. Hint: When you calculate the individual percentage of sand, silt, and clay, they should add up to 100%. An example analysis is shown in the lab. o #1: Camp Fresno, Dinkey Creek 60% Sand, 25% Silt, 15% Clay. o #2: CSUF Farm, Barstow Ave. 35% Sand, 50% Silt, 15% Clay. o #3: Farm Soil, Whitesbridge Rd., West Side, San Joaquin Valley 10% Sand, 60% Silt, 30% Clay. o #4: San Joaquin River Sediment 98% Sand, >0% Silt, 2% Clay.

Geology Name_____________________ Sediment and Sedimentary Structures lab report o Hint: When you calculate the individual percentage of sand, silt, and clay, they should add up to 100%. An example is 2. Use the USDA (U.S. Dept. of Agriculture) soil classification triangle in the lab to assign a soil type name to each of the four soil samples. A soil type is given based on where the three lines cross. An example of this classification process is shown in the lab. o #1: Camp Fresno, Dinkey Creek is Sandy Loam soil o #2: CSUF Farm, Barstow Ave. is Loam/Silt Loam soil o #3: Farm Soil, Whitesbridge Rd., West Side, San Joaquin Valley is Silty Clay Loam soil o #4: San Joaquin River Sediment is Sand soil 3. Perform a quick internet search on "what type of soil is best for plants". Are any of the four soils here good for growing a garden or starting a farm? Yes, Camp Fresno and CSUF Farm and Farm Soil are all classes of Loam. 4. What texture would you expect each of these samples to display based on the distance they traveled from their source -- that is, what would they feel like in your hand? #1 Coarse, well-draining. #2 Balanced, fertile. #3 Fine, fertile. #4 Coarse, fast-draining, gritty. 5. From where are most of the mineral particles in the soil on the east side of the San Joaquin Valley derived (see figure 11 )? How does it get to the valley? From Shaver, through the San Joaquin River, and ends up in Millerton Lake through to CSUF farm.

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Geology Name_____________________ Sediment and Sedimentary Structures lab report 6. What can you say about the relationship between the grain size distribution ( sorting ) of these soils and their location with respect to the Sierra Nevada mountains (approximately the grey area on the map) and the San Joaquin river? The relationship of grain size is that the closer the soil is to the river, the less sorting you will have, the same goes for the closer to the mountains but a little more sorted in those regards. Part 4: Interpreting sedimentary structures in rock 1. Sample Q: What features in this sample allow you to recognize its bedding? The lines from the bedding and the angle of the lines and the way there are patterns in the sediment show reveal the bedding. 2. Why do you think some beds in Sample Q are thicker than others? Some of the I think the steeper the angle of the bed is, the more falls of at a time, so the steeper parts of the bedding have larger beds. 3. Sample R: Look at the cross-bed angles, grain size, and sorting. Was this sand deposited by wind or by water? Explain, using the angle of cross-bedding you measured with your protractor as an argument for your response. Wind was the cause of deposition because when sediment is deposited by water it is around 15 degrees, this was not near 15 degrees. 4. How can you explain the fact that the cross-beds in Sample R slope in opposite directions? What can you say about the direction(s) the current flowed or wind blew? I would assume it was the differentiation over time with the direction of wind and the accessible airflow to the rock, surely it changed many times over the hundreds of millions of years. 5. In what type of depositional environment could Sample R have been deposited? (Interesting note: this rock is from the southern Mojave Desert, and is nearly 500 million years old!) An Eolian environment. 6. Sample S: Which side of these asymmetrical ripples is steep, and which is shallow? (Use A and B or left and right to describe it.) A is steeper and B is shallower. 7. Which way was the current moving when Sample S was deposited? From (A to B), (B to A), or (Back and Forth)? The current is moving from B to A. 8. Suggest a type of depositional environment in which Sample S could have been formed. A Fluvial, or river environment, because of the clear indications of water deposition.

Geology Name_____________________ Sediment and Sedimentary Structures lab report 9. Sample T: Imagine you're holding this rock in your hand and can flip it over to look at the other side. Which side of Sample T was "up" during its formation, the side in the image (marked with B) or the reverse side? The B side is a reversed version of the original cracks, so the other side was ‘up”. 10. Name two environments in which mud cracks like Sample T could form. A lakebed, or an intertidal zone.

Lab 11

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