This slide illustrates the texture of a typical large volume ignimbrite. It consists of fist-sized dacitic pumice clasts and small sparse lithics in a crumbly, finer grained matrix. Such rocks are very rapidly eroded, and are thus not well preserved or exposed in temperate regions. This example is from the 4.6 million year old Real Grande ignimbrite which has a volume of the order of 500 cubic kilometers. Landsat image of Cerro Galan volcano is shown in Slide 9--Part I. (Figure 10.22).

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