UGA Stratigraphy Lab

The data is in the strata

Tools for field work

Note-taking forms (pdf files)

Estimating true thickness of covered intervals where outcrop is oblique to dip

1) Measure the true strike of the strata (θstrike)

2) Measure the true dip of the strata (δ)

3) Measure the azimuth of the road (θroad)

4) Calculate the angle (β) between the road and the strike of the strata as β = | θroad - θstrike |

5) Calculate the apparent dip (α) of the strata along the road as α = arctan [sin(β) ⋅ tan(δ)]

6) Measure the apparent thickness (t) of the covered interval along the road using a Jacob staff set to the apparent dip of the strata along the road (α)

7) Calculate the true thickness (T) of the covered interval as T = t ⋅ [cos(δ) / cos(α)]

Estimating the vertical distance between two horizontal beds with a rangefinder and clinometer

1) Using a laser rangefinder, measure the distance from you to the lower bed (a). Using a clinometer, measure the vertical angle to the bed (alpha).

2) Using the laser rangefinder and clinometer, make the same measurements for the upper bed (b and beta).

3) Solve for the vertical distance between the beds (V), with
V=b sin(beta) - a sin(alpha)

Derivation