Archean felsic volcanic rocks in felsic rocks. Timing of felsic volcanism and tectonic constraints can be identified by radiometric dating and isotopic analysis. In Archean, underwater eruptions of felsic lava were common. Submarine eruption is evident by coarse volcanic breccia formed in situ, hyaloclastite or underwater pyroclastic deposits (clastic rock, composed of tephra only). Since felsic magma is viscous, volcanic eruptions that form dacite or rhyolite are explosive and violent. The Archean felsic eruption may be assigned to Vesuvius eruption type in the present day. Submarine rhyolitic flows were widespread in Archean but it is uncommon in the modern volcanic environment. Viscous felsic eruption
Blake River Megacaldera Complex respect to both hydrothermal Cu-Zn massive sulfides and gold-rich massive sulfides. The Blake River Megacaldera Complex consists of mainly mafic to intermediate volcanic flows and less abundant felsic volcanic flows and intercalated pyroclastic rocks, which underwent three stages of major volcanic activity. The Blake River Megacaldera Complex is considered a supervolcano due to its great size and its multiple dikes and vents. The Misema Caldera is in the order of , making the complex similar to the Yellowstone Caldera in Wyoming, Lake Toba in Indonesia and strikingly similar in structure to the Olympus Mons caldera on Mars. As a result,