What are Stratigraphic Columns?

Stratigraphic columns are the traditional means of presenting measured geologic sequences as a figure. Information should be arranged with the youngest rock unit at the top and the oldest rock unit at the bottom. The column should consist of small boxes containing the symbol used on the map to identify the rock unit, and if the map is colored or if patterns are used, they should also appear in the box. The name of the rock unit is written adjacent to the box.

Brief descriptions of the units may be lettered to the right of the column, as in the figure, or the column may be accompanied by an explanation consisting of a small box for each lithologic symbol and for the other symbols alongside the column. Columns are constructed from the stratigraphic base upward and should be plotted first in pencil in order to insure spaces for gaps at faults and unconformities. Sections that are thicker than the height of the plate can be broken into two or more segments, with the stratigraphic base at the lower left and the top at the upper right.

Bedding and unit boundaries are drawn horizontally, except in detailed sections or generalized sections of distinctly nontabular deposits, as some gravels and volcanic units

The following elements of a stratigraphic column are essential and are generally keyed to the figure:
(1) title, indicating topic, general location, and whether the section is single (measured in one coherent course), composite (pieced from two or more section segments), averaged, or generalized;
(2) name(s) of geologist(s) and date of the survey;
(3) method of measurement;
(4) graphic scale;
(5) map or description of locality;
(6) major chronostratigraphic units, if known;
(7) lesser chronostratigraphic units, if known;
(8) names and boundaries of rock units;
(9) graphic column composed of standard lithologic patterns;
(10) unconformities;
(11) faults, with thickness of tectonic gaps, if known;
(12) covered intervals, as measured,
(13) positions of key beds; and
(14) positions of important samples, with number and perhaps data. Other kinds of information may be included also.

 Look at the stratigraphy columns on page 6a, page 6b and page 14a of Rocks, Rails and Trails as examples.