Lab 7: Deformation Flashcards
syncline
like a u (holds water like a sink)
anticline
like an A
where are the oldest rocks found in an anticline
the centre
where are the oldest rocks found in a syncline
outer edges
fold axis/hinge line
imaginary line that runs along the crest or central axis of a folded structure. represents the maximum curvature within the fold
trend
the compass direction of a linear or planar geological feature
plunge
indicates the angle at which the features inclines from the horizontal line
axial surface
theoretical plane that divides a fold into two symmetrical halves
non-plunging fold
does not incline significantly from the horizontal plane
plunging fold
significant angle from the horziontal plane
upright fold
rock layers remain nearly vertical+ axial surface is vertical
inclined fold
axial surface is inclined causing the rock layers to tilt
overturned fold
axial surface is nearly horizontal. same angle from horizontal plane of each arm
recumbent fold
axial surface is nearly horizontal. one limb may lie on top of another limb
footwall
the side of a fault you could stand on
hanging wall
the side of the wall you would have to hang onto
fault slip
total displacement along the fault of two points
dip-slip fault
movement is vertical
normal, reverse, thrust
normal fault
hanging wall moves down
reverse fault
hanging wall moves up
thrust fault
hanging wall moves up at an angle of 30 degrees or less
strike slip fault
primary movement is horizontal
left lateral - looking at fault, other side has moved left
right later - looking at fault other side has moved right
map symbol for horizontal bed symbol
cross
strike of vertical bed symbol
long cross
strike and dip symbol
dislocation symbol, if it includes the angle the angle will be written at the end of the short line
Normal fault symbol
circles (hanging wall just rolls downhill)
Reverse fault symbol
squares (squares help the hanging wall climb uphill)
Thrust Fault map symbol
triangles (triangles are aggressive and so it the word thrust
syncline map symbol
(points in the direction a ball would roll)
Points towards the centre
anticline map symbol
(points in the direction a ball would roll)
points away from the centre
right hand rule
thumb points downhill along the line that is perpendicular to the elevation cross sections
fingers point in the direction of the dip angle
what format must you write strike/dip
000/00
strike/dip
no decimals
rule of v’s in block block diagram
for whatever fucking reason, rule of v’s is actually with u’s. The bulge points in the direction that is downhill (of the strata or the fault)
How to do a Block diagram with topography
draw lines wherever there are strata
use the rule of v’s
draw the fault
point the direction of the river
Label the age of all of the strata - top is biggest number as in last to be deposited
***Draw symbols for each of the strata showing which was it dips (the dislocation symbol)
How to do a surface trace to find strike and dip
- any point where the solid line touches a contour line draw a circle.
- connect all your circles at each elevation with lines. The lines should all be parallel to each other
- Draw a line perpendicular to all the lines you just drew - this is your strike line
- Strike: Use right hand rule on your strike line. This will tell you which side to find the angle. Always take the angle from vertical North and go clockwise.
- Dip: Use the strike line and the scale on the map to find the actual distance between 2 lines along your strike line. Make a triangle with that number as your x and the change in elevation as your y. Solve for theta.
- Remember to write in Strike/Dip : 000/00 and LOTS
- Shade in the Areas that have coal underground - The areas that are higher than the coal seam line will have coal.
