Originally Posted by caverdan
Wouldn't a canyon be the lack of dirt thus being air instead of the mass or lack of mass that is now missing thus making it a canyon? In other words the weight of a canyon would be measured in air..... not soil.
Sounds like a thread hijacking topic. Just like a room which contains walls and floor I always considered a canyon to include the walls, floor, water etc...not just the space between them. So then it become a question of how deep within each wall is really the same layer/s that make up the canyon wall? We could approximate the weight of the air between the walls reasonably well though.