Exempel på pumice

• Concentrations of pumice clasts towards the base form trains of clasts that are traceable along the length of outcrops.

• Concentrations of accretionary lapilli and diffuse trains of small pumices define bedding in this thick ash bed.

• For selected ignimbrites, sanidine crystals were taken from fresh, unaltered pumice lapilli.

• Due to incomplete exposures, the dispersal characteristics of most pumice fallout deposits are poorly constrained.

• Widely dispersed plinian-type pumice fall deposits and ignimbrite are characteristic products of both explosive cycles.

• Lithic- and pumice-rich horizons may mark separate eruptive events.

• The presence of banded pumice near the top defines a compositional zonation of the ignimbrite.

• These tuffs are all considered to be ash flow deposits because they are unbedded and contain well-developed eutaxitic foliation and pumice pseudomorphs locally.

• In the sixth zone, an abrupt change to greyish pumice is encountered, and no crystals are seen.

• Particle-supported autotrophic biofilms were cultivated in external-loop airlift reactors at different pumice concentrations.

• Concentrations of pumice occur locally in the upper 20-30 cm of the ignimbrite.

• Lithic fragments are commonly embedded in the larger pumices.

• The alkali basalt lithic breccias pass abruptly upwards into banded pumice-bearing ignimbrite.

• The internal structure of the bedforms is massive, although openwork clusters of pumice occur at the crest and on the lee-side.

• For this purpose biofilms were grown as autotrophic and heterotrophic communities on pumice in an airlift loop reactor.