No, there cannot be appreciable erosion without rocks undergoing weathering. The context clearly states that "Erosion cannot be significant if the rocks are not weathered." Weathering is essential for erosion to be substantial or meaningful.

Weathering breaks down massive rocks into smaller fragments, which erosional agents like running water, wind, glaciers, and waves can then acquire and transport. Without weathering, rocks remain intact and massive, making it difficult for erosional processes to act effectively on them.

However, weathering is not a pre-condition for erosion to take place at all. Erosion can still occur without weathering, but it would not be significant or appreciable in scale. Weathering aids erosion by preparing rock materials for transportation, thereby making the erosional process more effective.