Final answer:
The statement is true; ignimbrite can form from the solidification of a pyroclastic flow, which is exemplified by the welded tuff created during the eruption of Mount Vesuvius.
Step-by-step explanation:
The statement, 'Ignimbrite may result from a pyroclastic flow', is True. Ignimbrite is a type of volcanic deposit that forms when a pyroclastic flow, which is a fast-moving current of superheated gas and volcanic materials, solidifies on the ground. This flow can be so hot that it is capable of welding together the volcanic ash and fragments it carries, creating a rock known as 'welded tuff', which is another name for ignimbrite. During the eruption of Mount Vesuvius in 79 AD, pyroclastic flows had a significant impact, destroying and preserving nearby cities such as Herculaneum and Pompeii, through their blanket of ash and dense, hot properties.