SEIRA'S blog

Explain the following statements:

1. Climate is the most important factor affecting weathering.

Climate is the most important factor because it affects the temperature and precipitation rates. Temperature affects the rate of plants to grow and also affects the expanding and contracting of rocks. The plant creates a crack between the rocks which leads to weathering. The precipitation rate affects the amount of rain fall, which weathers the rock (physical). Also acid rain affects weathering, which is a part of rain so there needs to be a high precipitation rate. Higher temperature and precipitation rate causes a higher rate of chemical reaction so it has more weathering in those environment.

2. Mineral composition, grain size of the rock, presence of line of weakness affect the rate of weathering.

Mineral composition affects the rate of weathering. Some minerals are permeable and others are impermeable. Impermeable rocks weather more because they do not let water pass through and the water breaks the rock. Permeable rocks weather less because they let water pass through without much resistance.

Grain size of rock affects weathering by how big or small the surface area of the rock is. For example, with bigger surface area, there is more possibilities that rain, wind, etc collides with rock, causing the rock to weather. Smaller size of grains tend to weather more than bigger size grain.

Presence of line of weakness makes the rock more liable to cracks to become smaller rocks. In between these cracks, water can get inside the rock. When the water is frozen, it expands and makes the rock crack even more. When the ice melts, the water seeps into the new cracks and restart the process. The more lines, the more area of the rock is touching to water that affects the amount of weathering, so there is more weathering.

These are examples of weathered rock, affected by the climate, and in the first picture you can see the rock weathered because water running through the line of the rock is weathering the rock.