Stratigraphic Mapping

This semester we excavated in contexts, combining natural strata with arbitrary levels. This was a useful pedagogical tool, but it left the task of identifying and interpreting strata within Units and across the overall excavation area until the laboratory analysis. Your task is to revisit the context notes, field logs, excavation summaries on the wiki, and field blogs and to identify the strata that we’ve excavated this semester. You should collaborate with the students writing excavation Unit summaries, so that each of you are consistent with your stratigraphic labeling. You should start by conducting analysis on a Unit-by-Unit basis. First identify natural strata; note all of the contexts that belong to each strata. For example, if you determine that the topsoil is Strata 1, and there were two contexts dug in Strata 1, you would note that Strata 1 = JBH10 & JBH 12. Present this information in a clear manner – a table with accompanying profile image would be best. Use the profile drawings to correlate the Strata with contexts. Occasionally the contexts won’t match up with levels drawn in the profiles. This may be because that level did not appear in the profile wall that the excavators mapped. If this happens, return to the excavation paperwork to situate the context within the unit stratigraphy. Also, consider the artifacts and features found in these units as general guides to interpreting or delineating strata.

Next, identify strata and features that occur across excavation units. A good place to start with this might be to examine each unit closely before they are backfilled. Excavation notes and photographs will be very useful in this process. When identifying contiguous strata, make a note of the depths that the strata appear in the units. This may give us an idea about historical landscape surfaces. All strata won’t necessarily appear in each unit.

Your final product should report this information in detail, and with illustrations. If a site map is available by December, you should integrate this into your report as well.

Helpful Hints: When using the profile drawings, please first scan them and digitize the drawing by re-tracing over the strata (in a Photo-shop or similar program). You will want to wait to label strata until your analysis is complete – so don’t add labels in immediately – your stratigraphic labels may be revised and may not necessarily correspond to those that the excavators identified when drawing the profiles. Munsell values are helpful, but they are not absolute indicators of stratigraphic differences, since everyone sees colors differently. Use the Munsell values as a guide to color similarity, and consider the subtle variations when identifying strata across units or within units.

Syllabus / 2008 Class Members and Field Blogs / Readings / Critical Responses / 2008 Excavation & Unit Summaries / Sample Field Forms / 2008 Images / References & Resources / 2008 Midterm Projects / 2008 Final Projects