Which type of volcano has a dome shape and is built from very thick lava?

The type of volcano characterized by a dome shape and constructed from very thick lava is indeed a dome volcano. Dome volcanoes are formed when highly viscous lava is expelled from a central vent, leading to a steep, rounded profile. The thick lava doesn't flow far from the vent, resulting in a pile-up of material that creates the dome shape.

This contrasts with other types of volcanoes, where the lava's viscosity varies, leading to different shapes and structures. For example, shield volcanoes are broad and gently sloped, formed from fluid lava that can travel great distances before solidifying. Composite volcanoes, on the other hand, are characterized by layered eruptions of both lava and ash, resulting in a more conical shape. Calderas are large depressions formed after the collapse of a volcano following a significant eruption, not primarily built up by thick lava. Each of these structures is influenced by the nature of the lava flow and the eruption style, highlighting the distinct characteristics of dome volcanoes.