Final answer:
Detrital rock fragments become more rounded and well-sorted as they move further from their source, due to weathering and transport mechanisms smoothing their edges and sorting them by size.
Step-by-step explanation:
Detrital rock fragments become increasingly rounded and well-sorted with increasing distance from their source area. Due to the processes of physical and chemical weathering, fragments from disintegrated rock undergo changes. As these particles are transported by water or air, they collide with each other and with other surfaces, which wears down their sharp edges, making them smoother over time.
The extent of this rounding is a key indicator of the distance from source a sediment has traveled. The more rounded the grains, the further they have been transported. Additionally, sediment that has traveled a greater distance tends to be better sorted, with grains being more uniform in size, compared to sediment that has not traveled far and shows a wider range of grain sizes.