It is one of the world's best preserved mineralized Neoarchean caldera complexes, containing well-preserved mafic-intermediate pillow lavas, pillow breccias, hyaloclastite and peperites, submarine lava domes and dome-associated breccia deposits.

The Sturgeon Lake Caldera contains a well preserved north facing homoclinal chain of greenschist facies metamorphosed intrusive, volcanic, and sedimentary layers.

This piecemeal caldera complex includes nearly 3,000 m (9,843 ft) of major subaqueously deposited intracaldera fill.

The Mattabi pyroclastic flow, with a thickness in excess of 800 m (2,625 ft) and a strike length of at least 30 km (19 mi), is the third and most voluminous eruptive event associated with the Sturgeon Lake Caldera.

It hosts the 12-Mt Mattabi massive sulfide deposit which is interpreted to have formed on and below the seafloor, the latter through the processes of pore-space filling and replacement.