EARTHSC 2GG3 Lecture Notes - Lecture 4: Volcanic Bomb, Silicate Minerals, Lapilli
11 Sep 2018
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Important to understand how they work to understand and predict volcanic energy (new zealand, iceland, and british columbia) Rhyolite: silica-poor (mafic) lavas, low viscosity, flow easily, gases escape easily, quiet eruptions, lava flows, ex. In explosive eruptions, tephra is ejected: small fragments of pyroclastic debris, an accumulation of tephra is a pyroclastic deposit, very nutrient-rich and important for chronology (dating) Volcanic domes: form around vents from the eruption of highly viscous silica-rich magma, exhibit explosive eruptions, small domes often form within the crater after an eruption. Maars and ice contact volcanoes or fissures landscaping: the violent interaction of magma and groundwater produces maars, roughly circular volcanic craters commonly filled with water. Ice contact volcanoes: erupt beneath or against glaciers, subglacial volcanoes erupt, rapidly melting ice and produce huge floods known as j kulhlaups, ex. National park and 700 mya at long valley, california. Washington state: an eruption could spread ash over vancouver.
