- #1
sepcurio
- 22
- 12
I can completely clear out all large rocks from my garden so it's just soil and pebbles down to about a foot. Then come next spring I find new large rocks again. Happens each year. This is a common problem for farmers and gardeners.
Causes I've considered include:
-- Ice heaves that push up rocks to the surface: But frost only goes down to the frost level in the ground (~4-8 ft) so it would have cleared out all the rocks to that depth long ago.
-- Buoyancy; the rocks "float" to the top of the soil: But the rocks are very dense. Sometimes more dense than the particles of soil.
-- Particle sorting: I'm not sure what this is called - when smaller particles fall to the bottom and larger particles move to the top of a container of mixed-sized, equally dense particles. This is my best guess so far, but wouldn't the Earth just be covered only with large rocks and no sand and dirt if this was a dominant geologic process?
Causes I've considered include:
-- Ice heaves that push up rocks to the surface: But frost only goes down to the frost level in the ground (~4-8 ft) so it would have cleared out all the rocks to that depth long ago.
-- Buoyancy; the rocks "float" to the top of the soil: But the rocks are very dense. Sometimes more dense than the particles of soil.
-- Particle sorting: I'm not sure what this is called - when smaller particles fall to the bottom and larger particles move to the top of a container of mixed-sized, equally dense particles. This is my best guess so far, but wouldn't the Earth just be covered only with large rocks and no sand and dirt if this was a dominant geologic process?