If a tree has grown out of the side of a rock cliff and a house was recently built on the land above causing the tree a lot more rain water to run off where the tree lives, it's roots have started to be exposed and are now growing faster and bigger with the increase of water. The rock eventually cracks and the tree falls down to the river.
Explain what is happening in this example using the words weathering or erosion and chemical, biological and or mechanical weathering.
In this example, several processes of weathering and erosion are occurring, including chemical, biological, and mechanical weathering.
1. Chemical weathering: This is the process by which the chemical composition of rocks is altered, leading to their breakdown. In this scenario, rainwater is drifting off the house built above the tree and seeping into the nearby rock cliff. Over time, the water absorbs various chemicals from the rock, such as minerals, salts, and acids. These chemicals react with the rock, causing it to weaken and eventually crack.
2. Biological weathering: This process involves the actions of living organisms that contribute to the degradation of rocks. The tree's roots are growing on the rock cliff, and as they absorb water from the increased runoff, they also exert pressure on the rock surface. The tree's roots have started to grow faster and bigger due to the excess water, leading to the expansion of the root system. As the roots grow and exert pressure on the rock, it weakens the structure further, accelerating the process of weathering.
3. Mechanical weathering: This form of weathering involves physical forces that break down rocks into smaller pieces without altering their chemical composition. In this scenario, the rock cliff is constantly exposed to the elements. Rainwater seeps into the cracks and crevices in the rock, and as it freezes and expands during colder temperatures, it exerts pressure on the rock, causing it to further crack and deteriorate over time. Additionally, the continual flow of water erodes the rock, gradually wearing it away.
Overall, the combination of chemical weathering (due to the reaction of rainwater with the rock), biological weathering (as the tree's roots grow and exert pressure), and mechanical weathering (caused by the freeze-thaw cycle and continual water flow) leads to the gradual degradation and weakening of the rock cliff. Eventually, this process causes the rock to crack, leading to the tree's collapse and ultimately falling down into the river.