volcaniclastics Flashcards
volcaniclastic rocks contain _____ percent of volcanic-derived sediments
> 25%
three types of volcaniclastics:
primary
secondary (epivolcaniclastics)
mixed pyroclastic-epiclastic
primary volcaniclastic should contain how many percent of clasts?
at least 75%
derived either from magma itself, or pieces of the country rock/magma chamber ejected from the volcanic edifice
pyroclastics
three types of primary volcaniclastics
autoclastic
hyaloclastics
redeposited
lava flows picking up loose pieces on the surface
autoclastics
proximal autoclastic
breccia
distal autoclastic
agglomerate
glassy breccia
hyaloclastics
how are hyaloclastics formed?
sudden cooling, interaction of lava with seawater/ice
eroded to proximity volcaniclastics
redeposited
epivolcaniclastics contain how many percent volcanic clast?
at least 10-25%
resulted from the weathering of volcanic rocks
epivolcaniclastics
mixed primary-epivolcaniclastics contain how many pyroclasts?
25-75%
this type of epivolcaniclastic is mixed through reworking of streams
mixed primary-epivolcaniclastics