Internal Processes / Volcanism & Plutonic Landforms - Subduction
Subduction & Accretion
denser
oceanic crust
lighter
continental crust
subduction forces densest material down
South American Andes
Subduction Profile:
scraping sea-floor sediment into trench
melting in
Asthenosphere
magma rises to surface
sub-surface (plutonic) features
volcanic chains
island arcs
Accretion
ancient island
/ landmasses added
build up of accreted "terranes" along plate edge
Sierra Nevada
formation
Alaska and western Canada
jamming & accretionary wedges
marine sediments filling basin
California - Great Valley Sequence
Next
