Geology Quiz: Sedimentary Processes and Depositional Environments

Question 1:

Which of the following is NOT a primary sedimentary rock?

Explanation: The correct answer is D) Marble. Marble is not a primary sedimentary rock; it is a metamorphic rock formed from the recrystallization of limestone under high temperature and pressure. The other options (Sandstone, Limestone, and Shale) are all examples of primary sedimentary rocks.

Question 2:

Which depositional environment is characterized by the accumulation of sediments at the mouth of a river where it meets the sea?

Explanation: The correct answer is B) Delta. A delta is a depositional environment formed at the mouth of a river, where the river's sediments accumulate and form a fan-shaped landform. Beaches (option A) are depositional environments along coastlines, deep ocean (option C) refers to the ocean floor, and glacial moraine (option D) is associated with glaciers, not rivers.

Question 3:

Which sedimentary process involves the breakdown and transportation of rock particles by wind, water, or ice?

Explanation: The correct answer is B) Erosion. Erosion is the process by which rock particles are broken down and transported by wind, water, or ice. Deposition (option A) refers to the settling of sediments, cementation (option C) is the binding of sediment grains, and compaction (option D) involves the squeezing together of sediment grains.

Question 4:

Which type of sedimentary rock is formed from the accumulation of plant or animal remains?

Explanation: The correct answer is C) Coal. Coal is a sedimentary rock that forms from the accumulation of plant remains in swampy environments. Conglomerate (option A) and breccia (option B) are both composed of coarse sediment grains, and sandstone (option D) is made up of sand-sized grains.

Question 5:

Which sedimentary structure is formed by the gradual upward decrease in grain size within a sequence of sedimentary layers?

Explanation: The correct answer is C) Graded bedding. Graded bedding is a sedimentary structure characterized by a gradual upward decrease in grain size within a sequence of sedimentary layers. Ripple marks (option A) are small wave-like features on the surface of sedimentary rocks, cross-bedding (option B) is the inclined layering within a single sedimentary layer, and mud cracks (option D) are polygonal cracks that develop when mud dries and shrinks.