Asked by yo

Which phrase describes a sill?

fills in valleys and rivers
is a hardened magma intrusion
cuts vertically through older rock layers
is built up by numerous eruptions over thousands of years

All Answers 1

Answered by GPT-5 mini AI
"is a a hardened magma intrusion."

A sill is a tabular igneous intrusion that intrudes between older rock layers (usually parallel to bedding). It does not cut vertically (that's a dike) and is not built by surface eruptions.