Erosion and deposition are actually two interconnected processes, not necessarily one happening before the other. It's more accurate to say that erosion prepares the material for deposition.

Here's how they work together:

* Erosion: This is the process of wearing away and transporting rock, soil, and other materials. It can be caused by wind, water, ice, or gravity.

* Deposition: This is the process of dropping or settling the eroded material in a new location.

The Connection:

Erosion creates the sediment that deposition later uses. Think of it like this:

1. Erosion: A river carves through a mountain, breaking off rocks and carrying them downstream.

2. Deposition: As the river slows down, it loses energy and the rocks settle to the bottom, creating a delta at the river's mouth.

In some cases, erosion and deposition might seem to happen simultaneously:

* A river erodes the bank on one side while depositing sediment on the other side.

* A glacier erodes the land it flows over, but also deposits the eroded material in front of it.

In summary, erosion is the "source" and deposition is the "result" of the material being moved. They are two sides of the same coin, constantly shaping the Earth's surface.