Stratovolcano Stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava, tephra, pumice and ash. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and hardens before spreading far due to high viscosity. The magma forming this lava is often felsic, having high-to-intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less-viscous mafic magma. Extensive
Musgrave Block and probably also of the Palgrave Caldera is that they represent hot spots along the Musgrave Block where significant magma flux penetrated, formed volcanic calderas with large subvolcanic granite intrusions, and associated mafic volcanism. The relationship of the large granite calderas to the 1050-1080 Ma volcanics has been postulated as one in which the granite calderas were the source for the intermediate and felsic volcanic rocks. The Bentley Supergroup Volcanics are a sequence of bimodal supracrustal volcanic rocks formed during the ~1080 Warakurna Large Igneous Province, and are widely considered comagmatic with the mafic to ultramafic Giles Complex intrusions. The