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
Body substance isolation a part of the National Standards Curriculum for Prehospital Providers and Firefighters. Types of body substance isolation included: It was postulated that BSI precautions should be practiced in environment where treaters were exposed to bodily fluids, such as: Such infection control techniques that were recommended following the AIDS outbreak in the 1980s. Every patient was treated as if infected and therefore precautions were taken to minimize risk. Other conditions which called for minimizing risks with BSI: or any combination of the above. Body substance isolation Body substance isolation is a practice of isolating all body substances (blood, urine, feces, tears,