Geology Reference
In-Depth Information
blocks and bombs
(>64 mm)
Pyroclastic Sediment
Classification (IUGS/BGS)
block tephra
bomb tephra
75
75
ash breccia
25
25
ash
lapilli tephra
lapilli ash
25
75
ash
(<2 mm)
lapilli
(64 - 2 mm)
(a)
blocks and bombs
(>64 mm)
Polymodal Pyroclastic
Rock Classificaton (IUGS)
pyroclastic breccia (blocks)
agglomerate (bombs)
75
75
tuff breccia
25
25
tuff
lapillistone
lapilli tuff
25
75
lapilli
(64 - 2 mm)
ash
(<2 mm)
(b)
Figure 5.7
Classification system based on the sizes of material, separate for
unconsolidated/modern (a) and rock record/ancient (b).
