Question

Which one of the following is NOT a sediment-gravity flow?

• A. Hypopycnal flow
• B. Cohesive debris flow
• C. Turbidity flow
• D. Mud flow

Answer 1

The Correct Option is A

To determine which option is NOT a sediment-gravity flow, we first need to understand what sediment-gravity flows are. Sediment-gravity flows are a type of mass wasting process where sediment, mixed with water or air, flows downslope under the influence of gravity. These flows can include different types such as debris flows, turbidity currents, and mudflows.

Let's examine each provided option:

1. Hypopycnal flow: This involves a type of flow where a river enters a standing body of water, like a lake or the ocean, with the river water being lighter than the water body. It is not driven primarily by gravity acting on sediment, but rather by density differences between the river and the receiving body of water. This is not considered a sediment-gravity flow.
2. Cohesive debris flow: This is a type of gravity-driven flow that involves a mixture of water and sediment. The sediment is cohesive in nature, making the flow more viscous. This is a sediment-gravity flow.
3. Turbidity flow: This is a current of rapidly moving sediment-laden water moving down a slope through water. It is caused by gravity and involves suspended particles within the flow. This qualifies as a sediment-gravity flow.
4. Mud flow: A mudflow is essentially a liquid-cohesive movement of materials with a high proportion of fine particles such as silt and clay mixed with water, making it a sediment-gravity flow.

Based on the explanation of each option, the correct answer is Hypopycnal flow, as it is not driven by sediment-gravity flow dynamics.