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
Substance 1987 the on-screen title is "Substance 1983–88") and different background colours are used; the Factory/Qwest release has a grey background, the Japanese VHS release, blue and the LaserDisc, turquoise. The video includes linking sequences which are animated to the accompaniment of instrumental sections from "The Happy One", an otherwise unreleased track from the "Technique" sessions. Substance 1987 Substance (also known as Substance 1987) is a compilation album by English alternative dance band New Order. It was released in August 1987 by Factory Records. The album compiles all of the band's singles at that point in their 12-inch versions, along with their