The Solid Earth - Chapter 7: Materials Extruded Flashcards
All volcanic eruptions emit large amounts of ____
gas
Due to their low silica content, ____ lavas are usually very fluid and flow in thin, broad sheets of streamlike ribbon
basaltic
True or false: occasionally, the movement of silica rich lava is too slow to be perceived
true
These are formed when fluid basaltic lavas congeal and form a relatively smooth skin that wrinkles as the molten lava advances
pahoehoe flows
A type of basaltic lava with a surface of rough, jagged blocks with dangerously shap edges and spiny projections
aa flow
How is magma like a soft drink?
As soon as pressure is reduced, the gases begin to escape
Name the assumed makeup of the gases emitted
Water vapor CO2 Nitrogen Sulfur compounds (sulfuric acid?) Hydrogen,Argon,Chlorine
When basaltic lava is extruded, the ____ escape quite freely
dissolved gasses
The gases in highly ____ magmas ae less able to escape
viscous
The flows associated with viscosity that include superheated gases expanding as they blow pulverized rock and lava from the vent. (the name of these particles)
pyroclastics
As the hot gasses expand explosively, the lava is disseminated into the fine fragments. When the hot ash falls, the glassy shards often fuse to form ____
welded tuff
What is the name of a frothlike lava ejected in larger pieces?
pumice
Pyroclastics the size of walnuts
lapilli
Pea sized particles of pyroclastics
cinders
Particles larger than lapilli are called ____ when they are made of hardened lava and ___ when they are ejected as incandescent lava
blocks, bombs
