lecture 4 Flashcards
what is stratigraphy?
characteristics of rock relating to layering
what are the different principles of stratigraphy, explained?
principle of horizontality: (most) rock layers are created horizontally
principle of continuity: allows us to map out the same rock layer over a large area
principle of uniformity: you know this
principle of superposition: you know this
how is layering caused?
by the stress and strain of tectonic planes
draw the way we quantify rock deformation
check notes
one way in which we know deformation on a strata has occured
what the strata is inclined rather than horizontal
what is a strike?
the direction of the horizontal line on a dipping bed
what is the dip direction and dip angle?
dip direction: direction of the maximum dip
dip angle: angle below the horizontal
what is fracture?
the discontinuity of rock mass
what is a joint?
a fracture that has not moved
what is a fault?
a fracture that has moved
what is a dip slip fault? and the two types
when vertical movement occurs on a fault
normal: caused by tension
reverse: caused by compression
what are strike dip faults?
when no vertical movement occurs on a fault
what is slikenslides:
smoothing of rock along a fault
what is fault breccia:
the breaking of rock along a fault
draw the diagram that define heaves and throws
check notes
descridd what is meant by Horst and graben
adjacent faults that dip in opposite direction
what effect can stress have on some rock
it can deform without fracture
what effect can low strain rate have on some rock
brittle rock can behave in a ductile manner
5 thing the fold of rock depends on
stress, temperature, confining pressure, time period and rock type
draw what a chevon, syncline and anticline look like
check notes
what are the ways of describing rock folds?
symmetrical, asymmetrical
isoclinal: limbs almos parallel due to compression
recumbant: fold overturned and plane almost vertical
what is unconformity?
periods of ground movements and tectonic deformation occurring between periods of sedimentation
what is topography? and how is affected?
the formation of the ground surface and is affected by the rock type as rock strata resistant to weathering form ridges and less resistant rock form valleys
what are the two types of rock bedding explained?
graded bedding: coarse-grained sediment at the bottom and finer-grained at the top
crossed bedding: layering at an angle to the main bedding plane
