Rock Deformation Flashcards
As rocks form, they often change shape or ____ due to plate tectonic activity.
Deform
Form mountains, trap oil and gas underground and make rocks weaker
Structures
Outside force on rocks
Stress
How rocks respond
Strain
Ductile strain makes:
Folds
Brittle failure makes:
Faults
and earthquakes
Some rocks never break and others only break (T/F)
True
Permanent Strain in Ductile Folds
Weak rocks (shale or salt) Deeply buried hot rocks
Permanent Strain in Brittle Faults
Strong rocks (granite, sandstone) Near-surface cool rocks
Rocks stretch to cover a wider space
Extension (stress type)
Rocks get smashed into a narrower space
Compression (stress type)
Rocks tear as they slide sideways
Shear (stress type)
Rifting and Spreading makes…
Rocks stretch
Collision and Subduction makes…
Rocks compact
Transform makes..
Makes tear
Extension = thinner and wider
Cold/strong rocks crack apart
Hot/weak rocks stretch
Divergent Boundaries
Crack between new continents`
Rift valleys
Slices of broken crust slide down
Fault blocks
Rocks stretch without much deformation
Mid-Ocean Ridge
Compression = thicker and narrower
Rocks break and bend at the same time
Convergent Boundaries
Cold rocks on the ocean floor break into slices and pile up inside the trench
Accretionary wedge/prism
Hotter rocks around the volcanoes bend and break, making NARROW mountains
Fold and thrust belts
Much wider zones of complicated folds and faults form when two big continents collide
Fold and thrust belts
Shear = sliced and torn apart
Strike-slip faults
Transform Boundaries
Long fault zones with some ‘drag’
Strike-slip faults
