Problem 11 - Biology Concepts and Applications

Question

The ___________ cycle is a sedimentary cycle. a. hydrologic b. carbon c. sediments and rocks d. living organisms

Step-by-Step Solution

Answer

The correct answer is c. sediments and rocks.

Step 1: Understand the Question

The question asks which of the given cycles is a sedimentary cycle. We need to identify the cycle predominantly related to the formation and movement of sediments and rocks.

Step 2: Analyze Each Option

Option a 'hydrologic' refers to the water cycle, which involves the movement of water in different states on, above, and below the Earth's surface. Option b 'carbon' cycle involves the movement of carbon through the atmosphere, hydrosphere, biosphere, and lithosphere but is more biochemical. Option d 'living organisms' is not a cycle, rather refers to biological processes.

Step 3: Identify the Sedimentary Cycle

Option c 'sediments and rocks' directly involves the breakdown, transportation, and deposition of rocks and minerals, forming sedimentary layers over time. This matches the definition of a sedimentary cycle.

Key Concepts

Rock Formation

Rock formation is a key process in the sedimentary cycle. It begins with the weathering of pre-existing rocks. These rocks can be igneous, metamorphic, or even sedimentary. Weathering breaks these rocks down into small particles.
There are two main types of rock weathering:

• Physical weathering: This includes mechanical breakdown like frost wedging or abrasion. It does not change the rock's chemical composition.
• Chemical weathering: This involves chemical reactions, altering the rock's minerals. For example, acid rain can dissolve minerals in rocks.

Once rocks are broken down, the particles are transported by natural forces. These forces include water, wind, and ice. Ultimately, these particles settle in a new location. Through geological time, layers of particles harden to form sedimentary rocks. The pressure of overlying materials and minerals cement these particles together, completing the rock formation process.

Erosion

Erosion is a key mechanism transporting particles within the sedimentary cycle. It involves the removal and relocation of soil, rocks, and minerals from one location to another. Erosion can occur through various forces:

• Water: Rivers and streams can carry particles great distances. This process shapes landscapes by carving valleys and creating riverbeds.
• Wind: In dry environments, wind can carry sand and dust across vast areas, forming features like dunes.
• Ice: Glaciers can transport rocks and sediment over great distances during their slow movement.

Erosion's effects are visible in landscapes worldwide, such as the Grand Canyon. By constantly moving and reshaping materials, erosion plays a crucial role in soil formation and the sedimentary rock cycle.

Mineral Deposition

Mineral deposition occurs after erosion has transported sediment. These transported sediments eventually settle and accumulate. This settling process is known as deposition. In the context of the sedimentary cycle, deposition forms the layers beginning sedimentary rock formation. There are compelling examples of deposition:

• Beds of sand laid down by rivers at the mouth of their flow, known as deltas.
• Basins at the bottom of seas and oceans, where fine particles accumulate over time.

As layers build, the lower layers are compressed by the weight above. Minerals like calcite or silica act as natural cements. They fill spaces between particles and harden over time. This process is called lithification, transforming loose sediments into solid rock. Understanding mineral deposition provides insight into how vast sedimentary formations like the sandstone arches of Utah form.