dacite
eklemetti | July 4, 2010So, I've had requests on the blog to help to do some defining of volcanologic terms on the blog, so I thought I'd try a new column called Eruptions Word of the Day. I'm not sure how often it will run, but let's give it a try.
Eruptions Word of the Day for July 5, 2010: Dacite
Dacite is a magma type defined by silica (SiO2) content between 63-68 (or 69) weight percent. That is the textbook definition, but some other typical characteristics of dacite lavas (or magmas) is the presence of certain minerals: plagioclase feldspar and hydrous minerals (containing water in their mineral structure)…