- Soil Soil Is The Unconsolidated Material On The Surface Of Earth That Supports The Growth Of Plants Soil Consists 100 1 1 (462.05 KiB) Viewed 39 times
- Soil Soil Is The Unconsolidated Material On The Surface Of Earth That Supports The Growth Of Plants Soil Consists 100 1 2 (123.32 KiB) Viewed 39 times
TA a Sand 80% sand FIGURE 5.2 60% sand 40% sand Clay 80% clay 60% clay 40% clay 20% clay 0% clay 20% sand 0% sand Soil is classified based upon the relative proportions of sand, silt, and clay-sized particles. Sand consists of grains 1/16 mm-2 mm in diameter, silt consists of grains 1/16 mm-1/256 mm in diameter, and clay consists of grains < 1/256 mm. How to read a triangular graph. See text for discussion. A soil classification chart is a three-sided graph drawn on an equilateral triangle. A triangular graph allows you to plot three variables (sand, silt, and clay) that sum to a constant (100 %). The base of the triangle shows the percent sand from 0% sand on the right to 40% sand 35% silt 25% clay 38 Chapter 5 Soils and Groundwater d 0% silt Percent Clay 20% silt 40% silt 60% silt ...i Percent Silt V Percent Sand 80% silt m Silt 100% sand on the right (figure 5.2a). The right side of the triangle shows the percent silt from 0% silt at the top of the triangle to 100% silt in the lower right cor- ner of the triangle (figure 5.2b). The left side of the triangle shows the percent clay from 0% clay in the lower left corner of the triangle to 100% clay at the top of the triangle (figure 5.2c). The dot in Figure 5.2d shows the location of a soil sample that is 40% sand, 35% silt, and 25% clay. Note that the percents of sand, silt, and clay must add up to 100%.
groundwater. The top of the phreatic zone is called the water table. If you look closely at unconsolidated material, you will notice that the grains do not fit tightly together. The spaces between the grains are called pore spaces. porosity = volume of pore space volume of sediment or rock The volume occupied by pore spaces is called the porosity and is usually stated as a percent. The porosity is influenced by grain shape, arrange- ment, and sorting (distribution of grain sizes). A well sorted sediment where the grains are mostly the same size will have a higher porosity than a poorly sorted sediment where the smaller grains can lodge in the spaces between the larger grains, thus reducing the porosity. Well sorted sediments typically have porosities of about 50%. Typical porosities in rocks range from about 1% to about 35%.
Q2 (1.5 pt) Determine the porosity of a pea gravel sample knowing that you were able to add 30 ml of water to 100 ml of sediment. Calculate the porosity of your sample stated as a decimal. Show your calculation. Calculate the porosity of your sample stated as a percent. Show your calculation. Q3 (1.5 pt) Determine the porosity of a sand sample knowing that you were able to add 20 ml of water to 100 ml of sediment. Calculate the porosity of your sample stated as a decimal. Show your calculation. Calculate the porosity of your sample stated as a percent. Show your calculation._. % Calculate the porosity of your sample stated as a decimal. Show your calculation. Q4 (1.5 pt) Determine the porosity of a clay sample knowing that you were able to add 10 ml of water to 100 ml of sediment. Calculate the porosity of your sample stated as a percent. Show your calculation. % % Q5 (0.5pt) Based on what you calculated above, which type of sediment (gravel, sand, clay) has a higher porosity?