Question

1. if we were to visit the grand canyon in 1 million years, we might be able to see more layers exposed. what variables would determine how much the river eroded the rock in that million years?

Explanation:

The key variables relate to the river's erosive power, the rock's resistance, and environmental conditions that influence both. These include:

1. River discharge/flow volume: Higher flow increases erosive force.
2. Sediment load in the river: More sediment acts as abrasive tools for erosion.
3. Rock type/strength: Softer, less resistant rocks erode faster than hard, compacted ones.
4. Climate patterns: Changes in rainfall (affecting flow) or freeze-thaw cycles break down rock.
5. Tectonic activity: Uplift of the region can increase the river's gradient and erosive energy.
6. Vegetation cover: Less vegetation leads to more runoff and sediment entering the river, boosting erosion.

Answer:

The main variables determining the amount of erosion are:

• River flow volume and velocity
• Sediment load carried by the river
• The type and resistance of the bedrock
• Long-term climate changes (rainfall, temperature)
• Tectonic uplift or subsidence of the area
• Vegetation cover in the surrounding watershed