What distinguishes a joint plane from a fault plane?

No movement along a joint plane, movement along a fault plane

Joint plane has movement, fault plane has none

Both always have equal movement

Joint planes occur only in metamorphic rock

The axial plane of a fold

divides the fold into two nearly equal halves

is the erosion surface under younger beds

is the horizontal line on a bed

is the plane of mineral alignment

How is the attitude of a plane expressed?

By strike and dip, with dip measured perpendicular to the strike

By dip measured along the strike

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Define geological planes with figures

Short answer

Geological planes are flat surfaces in rock masses, including bedding planes (separate sedimentary beds), joint planes (fractures with no movement), fault planes (fractures with displacement), foliation/cleavage planes (mineral alignment in metamorphic rocks), axial planes (divides a fold symmetrically), and unconformity planes (erosional surface). The orientation of a plane is given by its strike and dip.

Define the various geological planes with suitable figures.

A geological plane is a more or less flat surface in a rock mass that separates rocks of different properties or along which the rock can break or move. The common geological planes are:

Bedding plane - the surface that separates two successive beds of sedimentary rock.
Joint plane - the surface of a fracture along which there has been no movement.
Fault plane - the surface of a fracture along which the rock has moved.
Foliation / cleavage plane - planes of parallel alignment of minerals in metamorphic rocks.
Axial plane - the imaginary plane that divides a fold into two nearly equal halves.
Unconformity plane - an erosion surface separating younger and older rocks.

  ------------------  bedding plane
  ------------------
  ====/============   fault plane (with movement)
     /   |  |  |      joint plane (no movement)

The orientation of every plane is expressed by its attitude: strike (bearing of the horizontal line on the plane) and dip (maximum inclination, measured perpendicular to the strike).

        horizontal plane
        ______________
       /   strike    /|
      /____________ /_|  dip angle
     inclined plane

✓ Answer checked by Claude Opus 5.5 (high effort)

Primary and secondary structures; strike and dip · Engineering Geology I, chapter 5 · asked 2×

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Define geological planes with figures

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