Sedimentary Rocks and Weathering

Practice exam questions written by Timothy H. Heaton,
Professor of Earth Sciences, University of South Dakota

Click the circle by an answer with the mouse, then click on the Submit button to get a response. You will be told if your answer is correct or not and will be given some comments.

  1. What process results in the exfoliation (concentric fracturing) of granite domes?
    Dissolution.
    Frost wedging.
    Hydrolysis.
    Oxidation.
    Unloading.

  2. Which type of weathering creates clay minerals?
    Dissolution.
    Frost wedging.
    Hydrolysis.
    Oxidation.
    Unloading.

  3. Which type of weathering works most effectively on limestone?
    Dissolution.
    Frost wedging.
    Hydrolysis.
    Oxidation.
    Unloading.

  4. Which type of weathering produces cones of talus?
    Dissolution.
    Frost wedging.
    Hydrolysis.
    Oxidation.
    Unloading.

  5. Which types of weathering are significantly promoted by acid rain (two correct answers)?
    Dissolution.
    Frost wedging.
    Hydrolysis.
    Oxidation.
    Unloading.

  6. Chemical weathering always results in the creation of what kind of minerals?
    Felsic minerals.
    Mafic minerals.
    High-temperature minerals.
    Low-temperature minerals.
    Non-silicate minerals.

  7. Which of these silicate minerals is likely to be chemically weathered most easily?
    Augite (pyroxene).
    Hornblende (amphibole).
    K-feldspar.
    Kaolinite (clay).
    Olivine.
    Quartz.

  8. Which of these silicate minerals is unlikely to be chemically weathered?
    Augite (pyroxene).
    Hornblende (amphibole).
    K-feldspar.
    Kaolinite (clay).
    Olivine.
    Quartz.

  9. Chemical weathering in a soil tends to create what shape of rock fragments?
    Angular.
    Columnar.
    Cubic.
    Spheroidal.
    Tetrahedral.

  10. What is the definition of erosion?
    The accumulation of sediment following transportation.
    The disintegration and decomposition of rocks at or near the earth's surface.
    The dissolution of soil components.
    The incorporation of and transportation of material by mobile agents such as water, wind, and ice.
    The transfer of rock material downslope under the influence of gravity.
    The washing out of fine soil components.

  11. What weathering products are most easily transported by water?
    Clays in suspension.
    Dissolved ions.
    Pebbles.
    Sand grains.

  12. What is the primary agent of sediment transportation from sites of weathering to sites of deposition?
    Glaciers.
    Gravity.
    Plants and animals.
    Rivers.
    Wind.

  13. Which weathering products, if present, are deposited first when a river reaches the ocean?
    Clays in suspension.
    Dissolved ions.
    Pebbles.
    Sand grains.

  14. Which weathering products, if present, are not necessarily deposited when a river reaches the ocean?
    Clays in suspension.
    Dissolved ions.
    Pebbles.
    Sand grains.

  15. In which climate is chemical weathering likely to occur most rapidly?
    Desert.
    Polar region.
    Tropical forest.

  16. What is the definition of eluviation?
    The accumulation of sediment following transportation.
    The disintegration and decomposition of rocks at or near the earth's surface.
    The dissolution of soil components.
    The incorporation of and transportation of material by mobile agents such as water, wind, and ice.
    The transfer of rock material downslope under the influence of gravity.
    The washing out of fine soil components.

  17. What is the deepest horizon in a soil, composed of partly weathered bedrock?
    A.
    B.
    C.
    E.
    O.

  18. What soil horizon is composed mostly of organic matter?
    A.
    B.
    C.
    E.
    O.

  19. What soil horizon is light colored because of eluviation and leaching?
    A.
    B.
    C.
    E.
    O.

  20. Which type of soil develops in mid-latitude forests?
    Laterite.
    Pedalfer.
    Pedocal.

  21. Which type of soil is heavily leached, with most of the calcite and silica removed?
    Laterite.
    Pedalfer.
    Pedocal.

  22. Which type of soil contains caliche due to minor leaching?
    Laterite.
    Pedalfer.
    Pedocal.

  23. What is the definition of leaching?
    The accumulation of sediment following transportation.
    The disintegration and decomposition of rocks at or near the earth's surface.
    The dissolution of soil components.
    The incorporation of and transportation of material by mobile agents such as water, wind, and ice.
    The transfer of rock material downslope under the influence of gravity.
    The washing out of fine soil components.

  24. What rock is defined as having angular-shaped clasts?
    Breccia.
    Conglomerate.
    Sandstone.
    Shale.
    Siltstone.

  25. What is the most abundant type of sedimentary rock?
    Conglomerate.
    Evaporites.
    Limestone.
    Sandstone.
    Shale.

  26. Which sedimentary rock tends to be fissile?
    Conglomerate.
    Evaporites.
    Limestone.
    Sandstone.
    Shale.

  27. Which sedimentary rock is usually composed of mostly quartz?
    Conglomerate.
    Evaporites.
    Limestone.
    Sandstone.
    Shale.

  28. Which sedimentary rock is made of clay minerals?
    Conglomerate.
    Evaporites.
    Limestone.
    Sandstone.
    Shale.

  29. Which sedimentary rock is made of calcite?
    Conglomerate.
    Evaporites.
    Limestone.
    Sandstone.
    Shale.

  30. Which sedimentary rock contains the largest clasts?
    Conglomerate.
    Evaporites.
    Limestone.
    Sandstone.
    Shale.

  31. Which sedimentary rock contains the smallest clasts?
    Conglomerate.
    Evaporites.
    Limestone.
    Sandstone.
    Shale.

  32. What is a sandstone with a high feldspar content?
    Arkose.
    Chert.
    Graywacke.
    Quartz sandstone.
    Siltstone.

  33. Which rock is not a form of limestone (i.e. made of calcite)?
    Chalk.
    Chert.
    Coquina.
    Micrite.
    Travertine.

  34. Which of these rocks is not detrital (clastic)?
    Arkose.
    Breccia.
    Dolostone.
    Graywacke.
    Quartz sandstone.

  35. What is coal made of?
    Altered peat.
    Augite.
    Biotite.
    Hornblende.
    Olivine.

  36. Which type of limestone is inorganic in origin?
    Chalk.
    Coquina.
    Coral reef.
    Micrite.
    Oolitic limestone.

  37. What environment are graded beds formed in?
    Beach sands.
    Deep-sea fans.
    Lagoons.
    Reefs.
    Swamps.

  38. Which sedimentary rock type is likely to be formed in the most offshore environment?
    Conglomerate.
    Limestone.
    Sandstone.
    Shale.
    Siltstone.

  39. What separates layers of sedimentary strata?
    Bedding plains.
    Cement.
    Cross beds.
    Graded beds.
    Ripple marks.

  40. What term is used to describe rocks forming at the same time in adjacent environments leading to lateral changes in rock type?
    Compaction.
    Eluviation.
    Facies.
    Grading.
    Sorting.

  41. What term refers to the degree of uniformity of clast size in sedimentary rocks?
    Compaction.
    Eluviation.
    Facies.
    Grading.
    Sorting.

  42. What is a geological specialist who studies layered rocks and correlates layers from different localities?
    Paleontologist.
    Geophysicist.
    Petrologist.
    Stratigrapher.
    Structural geologist.

Please report any problems or errors to Dr. Heaton.