Final answer:
Contact metamorphism is the type of metamorphism that occurs due to heat alone, without differential stress, typically around the intrusion of magma.
Step-by-step explanation:
Metamorphism due to heat alone, without differential stress, is called contact metamorphism. This type of metamorphism occurs when rocks are heated by the intrusion of hot magma from the Earth's mantle, leading to changes in the rock's mineralogy and texture without the application of significant pressure or stress. Contact metamorphism can result in the creation of non-foliated or massive metamorphic rocks which may share some similarities with igneous rocks.