Key Words: GEOLOGY UNIT 1.4


Bed - a unit of sedimentation, which can vary considerably in thickness

Bedding plane - marks the break between beds. Represents a break in sedimentation, a change in the composition or grain size, or a change in colour of the sediments

Dip - the maximum inclination of a bed measured from the horizontal using a clinometer

Strike - the direction at right angles to the dip. There is zero dip in this direction. It is a bearing measured from north using a compass

Apparent dip - a dip measure to be less than the maximum inclination

Tension - the force trying to pull rocks apart-the Earth's crust will be shortened

Shear forces - the forces which act along a plane in the rock and promote sliding along that plate

Competent - rocks that are strong and brittle but also tend to joint and fault

Incompetent - rocks that are weak and plastic that tend to fold and develop cleavage

A Joint - a fracture in competent rocks along which no observable movement has occured

Tectonic joints - formed as a result of folding and cause tension joints parallel to the acial plane and cross joints…


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