Chapter 7 SedimentaryRocks Lab Workbook

PRE-LAB QUESTIONS 1. What are the three categories of sedimentary rocks? Biogenic, Clastic, and Chemical 2. True or False? Mechanical weathering involves the dissolution or decomposition of sediments. False 3. Clastic sedimentary rock textures are described in terms of: (Select all that apply.) a. Grain shape b. Grain source c. Grain size d. Grain sorting 4. Which of the following sedimentary rocks are clastic? (Select all that apply.) a. Mudstone b. Chert c. Sandstone d. Coal e. Rock Salt 5. Chemical sedimentary rocks form when crystals ___ from an aqueous solution. precipitate 6. Using the information in Table 4 (next page), give an example of a possible environment where a fine-grained, well-rounded, and well-sorted quartz sandstone would form. Desert, Beach, Shallow Sea, River, or Delta ©2016, eScience Labs Sedimentary Rocks Sedimentary Rocks Sedimentary Rocks

©2016, eScience Labs Sedimentary Rocks Sedimentary Rocks Sedimentary Rocks

EXERCISE 1 DATA SHEET Table 6. Sedimentary Rock Identification Rock Sample Rock Type (Clastic, Biogenic, or Chemical) Composition Texture (Grain size, etc.) Rock Name Other Observations G Clastic Quartz, Feldspar Group Rough, granular Sandstone Beige color, potentially magnetic H Clastic Clay, Quartz Fine Mudrock Black color I Chemical Calcite Granular Limestone Gray J Chemical Silicates Fine Yellow Jasper Brittle, White streak, vitreous luster K Clastic Pebbles, sand Coarse Conglomerate Rounded clasts L Chemical Calcium sulfate Fine Gypsum White, soft ©2016, eScience Labs Sedimentary Rocks Sedimentary Rocks Sedimentary Rocks

EXERCISE 1 POST-LAB QUESTIONS 1. Compare the environments listed in Table 4 (below) and your descriptions and rock names in Table 6 (Data Sheet). Identify the possible environment(s) for each sample below. G: River, beach, deserts, and deep sea. H: Deep sea, lake. I: Oceans, lakes, desert. J: Volcanic K: Beach, River L: Lake, Shallow Sea, Deep Sea Table 4. Depositional Environments and Corresponding Rock Properties Environment Rock Type Composition, Texture, and Other Features Desert Clastic Very well-sorted, well rounded sands; cross-stratification common Glacier Clastic Poorly sorted, angular to rounded grains (mud–gravel) River Clastic Well-sorted, angular to rounded grains (mud–gravel) Lake Clastic Mud–gravel, laminations and grading common Lake Chemical Crystalline/microcrystalline precipitates (halite, gypsum, silica, iron, etc.) Lake Biogenic Plant and/or animal (shell) fragments Beach Clastic Well-sorted, well-rounded grains (sand and gravel) Delta Clastic Well to poorly sorted, rounded grains (mud–sand) Shallow Sea Clastic Well-sorted, rounded sands Shallow Sea Chemical Ooids (spherical calcite grains with laminations) Shallow Sea Biogenic Shells and shell fragments Reef Biogenic Shells and shell fragments, corals Deep Sea Clastic Mostly mud (occasional fine sand), laminations and grading common Deep Sea Chemical Microcrystalline precipitates (silica) ©2016, eScience Labs Sedimentary Rocks Sedimentary Rocks Sedimentary Rocks