Landforms

The Changing Landscape

The Earth is very old and continuously changing.

The Earth's landforms are the result of natural processes.

Landforms are continuously being built up and broken down through the combined action of land deformation processes (tectonics and volcanism), freezing and thawing cycles, gravity, wind, water, the Sun, plants, and animals.

Landscapes have observable features and patterns that we can use to identify them.

New rocks and landforms are derived from old rocks and landforms as the materials they consist of are changed by ongoing geological processes.

If we understand the processes that have formed our environment, we will be better able to protect our Earth in the future.

New rocks are derived from old rocks as the materials they consist of are rearranged and changed by natural processes. Many of these processes occur on a very large scale. For example, it has been calculated that a windstorm can carry up to a million tonnes of dust for more than 3000 kilometres.

The land is constantly being washed, blown, and worn away by rain, ice, snow, wind, gravity, and the Sun. This process of erosion is sometimes very slow, such as the erosion of rock by wind. Af other times, it can be very fast, such as when floods wash away large volumes of soil and rock. The term erosion can mean transportation, but more often it is defined as the whole process of weathering and subsequent transportation. Weathering can be a physical process, for example, through the action of wind, rain, and ice. It can also be a chemical process, such as when water reacts with carbon dioxide and forms carbonic acid, which then reacts with limestone.

Mass wasting is the term for bulk movement of debris down slopes under the force of gravity. Mass wasting does not rely on running water or moving ice to carry the load. However, water can be a factor in that it increases the mass of a soil by filling in the spaces between the particles. Mass wasting is an important aspect of New Zealand geology because of the particular rock structures, climate, and steep topography here. The main point for students to understand is the difference between mass wasting and grain‑by‑grain attrition.