EXPLORATION: Weathering and Erosion

In order to understand weathering and erosion, you first need to understand the concept of gradation. 

Gradation is the process of levelling the land by means of moving agents like rivers, winds, sea and waves. The highlands are made low by erosion or wearing away and the lowlands are raised by adding the eroded material by the process of deposition. In spite of the fact that gradation has continued for eons, the land has not become level. This is because there is constant earth movement which raises mountains and plateaus and therefore gradation is a continuous process.

In a sense, you can consider the forces of gradation and tectonics as one of an ongoing battle. Tectonic forces pushes the land upwards and gradation wears it down in a constant process of levelling. The levelling takes place in two ways - tearing down, or erosion, and filling in, called deposition. 

The cycle of gradation is that of weathering, transportation and deposition. 

In this photo below, you can see how glacial silt has been deposited at the mouth of a river going into a lake.