Origin of Sedimentary Rocks Geology Worksheet-GMUM.

ORIGIN OF SEDIMENTARY ROCKS Sedimentary rocks are derived from the weathering and erosional debris of other rocks. This material is deposited at Earth’s surface, under conditions of normal temperature and pressure. The major processes involved in the formation of sedimentary rocks are (1) physical and chemical weathering of the parent rock material; (2) transportation of these weathered products by running water, wind, gravity, or ice; (3) deposition of the material in a sedimentary basin; and (4) compaction and cementation of sediment into solid rock. These processes operate at or near Earth’s surface and are therefore observable. A significant result of the transportation and deposition of sediment is the sorting and segregation of the parent rock material into deposits of similar grain size and composition. Materials similar in size and weight are washed and winnowed by wind and water, and deposited in a sedimentary environment according to the level of mechanical energy operating at the time of deposition. For example, coarse gravels may be deposited in an alluvial fan near a mountain front or on a river bar, whereas sand is transported down-stream to the sea to be concentrated on a beach. Currents and wave action wash away the finer material, which is deposited ultimately in an environment of low mechanical energy, such as a marsh or lagoon. Chemical sorting occurs contemporaneously; the more soluble materials dissolve and are removed in solution and may later be precipitated in a lake or an ocean basin. The term sedimentary environment refers to the place where the sediment is deposited and to the physical, chemical, and biological conditions that exist there. The diagram on the next page shows, in a general way, the regional settings of some major sedimentary environments. The description of each environment summarizes some of the important characteristics of the sedimentary rocks formed in each environment. 1 2 6:19 Il LTE learn.vccs.edu construct your response in clear sentences, and be sure that your response answers the question asked. Question 1 1 pts List the environments in which shale accumulates. What does each of these have in common with the others? 12pt Paragraph B O words p < Question 2 1 pts In what two ways is CaCO3 extracted/precipitated from seawater? (Hint: think about how CaCO3 is formed in oolitic limestone compared to how it forms in coral reefs) 12pt v Paragraph B 6:19 l LTE learn.vccs.edu Question 9 1 pts What is an arkose? How does it differ from a quartz sandstone? 12pt v Paragraph B O words p < Question 10 1 pts Why does sandstone form in so many different environments? (Hint: Think about its mineral composition, how that mineral weathers, and how grain size relates to energy of depositional environment) 12pt v Paragraph B IIIC 山 Х 6:19 Il LTE learn.vccs.edu D Question 3 1 pts What is the process that forms clay minerals? What minerals are altered to form clays? What element must be present in those minerals? 12pt v Paragraph O words p < Question 4 1 pts Why is olivine a rare mineral in sandstone-even on the beaches of volcanic islands? (Hint: think back to Unit 6 on Weathering) 12pt v Paragraph B 1 o – Х