Measuring Thickness of Stratigraphic Units

There are several tools used to measure the thickness of sedimentary rock units.

Probably it is easiest to use a tape measure (photo A) or a telescoping measuring rod (photo B).

 

Photo A

Photo B

 

Another approach is to use a site level calibrated to the height of the user's eye level. The photo to the left demonstrates calibration of the site level. Jill looks through the site level at the tape measure and uses the bubble level to determine the height of her eye. Jim helps by moving his finger along the tape until it is at the point she can see through the site level.

Using this calibrated eye height can be useful when it is difficult to directly measure the outcrop thickness.

 

Thickness of rock units should always be measured perpendicular to bedding. Typically the thickness measurements of the lowest and highest units in a rock outcrop represent minimum thicknesses because the base of the lowest and the top of the highest units are covered or not exposed.

 

Station 2
Measuring thickness of stratigraphic units