Pyroclasts cinders

However, fumarolic activity, ash deposits on ice, and Pleistocene lava flows having K-Ar dates less than 0.1 Ma have been reported from Mt. Melbourne and The Pleiades in northern Victoria Land (LeMasurier 1990). In addition, small basaltic cinder cones, lava flows, and pyroclastic deposits occur at scattered locations in northern and southern Victoria Land. 

The term lapllll is applied to pyroclastic material that has a diameter varying from approximately 10 to 50 mm (Fig. 1.5). Cinder or scoria is irregular-shaped material of lapilli size. It usually Is glassy and fairly to highly vesicular. 

Because of the occurrence of permeable contacts, close jointing, pipes, and the possible presence of tunnels and cavities, recent accumulations of basaltic lava flows can prove highly leaky rocks with respect to watertightness. Lava flows frequently are interbedded, often in an irregular fashion, with pyroclastic deposits. Deposits of ash and cinders tend to be highly permeable. 

Figure 17.7 Volcanoes come in many shapes and forms. A classically shaped volcano may he a cinder cone formed by ejection of rock and lava, called pyroclastics, from the volcano to produce a relatively uniform cone.

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