What is a sill in geology?
Q: What is a sill in geology?
A: A sill is a flat sheet-like intrusion in geology.
Q: How is a sill formed?
A: A sill is formed by molten magma pushing between older layers of rock, following planes or weakened areas in the existing rocks.
Q: Does a sill cut across preexisting rocks?
A: No, a sill does not cut across preexisting rocks, unlike dykes.
Q: What kind of existing rocks can a sill be found in?
A: A sill can be found in sedimentary rock, beds of volcanic lava or tuff, or metamorphic rock.
Q: How are sills fed?
A: Sills are fed by dykes as they form from a lower magma source.
Q: What does it mean when a sill cools and crystallises?
A: When a sill cools and crystallises, it becomes a solid rock formation.
Q: Does a sill have a similar shape to a dyke?
A: No, a sill has a flat sheet-like shape, while dykes are more cylindrical.
