 Complete the following phrase:  Volcanoes with a felsic melt composition produce extremely explosive eruptions that can inject massive quantities of dust and aerosols high into the atmosphere. These particulate emissions are potent climate forcing agents, and can provoke a wide variety of responses including warming, cooling, and rainwater acidification. The climatic response depends on the altitude of the dust cloud as well as the size and composition of the dust. Some volcanic silicates cooled extremely quickly, created a glassy texture; their dark colour and reflective nature absorb some radiation and reflect the rest. Such volcanic material injected into the stratosphere blocks solar radiation, heating that layer of the atmosphere and cooling the area beneath it. Wind patterns can distribute the dust over vast geographic regions; for example, the 