Why are many peaks in the Wrangell Mountains volcanic in origin?

Many peaks in the Wrangell Mountains are volcanic in origin because the range is composed of composite volcanic mountains that rest upon a foundation of metamorphosed Paleozoic and Mesozoic sedimentary and igneous rocks.1

These mountains formed through volcanic activity, and while most of the summits are now extinct volcanoes, some remain geologically significant; for instance, Mount Wrangell is still considered active and continues to steam.21