North American Database of Archaeological Geophysics
North American Database of Archaeological Geophysics
Abstract/Summary:
Project Name: Richland Archaeological Project
Reference: Alt,
S., M. Hargrave and T. Pauketat. (2001). Geophysical Investigations at Cahokia
Outlying Settlements. Poster presented at the 66th Annual Meetingof the Society
for American Archaeology, New Orleans, LA.
Pfeffer Site (11S204) is
one of several early Mississippian settlements investigated by Dr. Tim Pauketat
(University of Illinois at Urbana/Champaign) and Susan Alt (UIUC) as part of
the NSF-funded Richland Archaeological Project. Pfeffer is the second largest
of four Mississippian mound centers in the central Silver Creek valley, Illinois.
Investigations in 2000 included controlled surface collections, mechanized stripping,
and the hand excavation of 16 structures and 112 pits. The single-post and wall
trench structures and many of the pits date to the Lohmann (A.D. 1050-1100)
and Stirling (A.D. 1100-1200) phases.
Prior to the UIUC excavations, Dr. Michael Hargrave (ERDC/CERL) conducted a
magnetic field gradient survey at Pfeffer. An area of 2,800 m2 was surveyed
using a Geoscan FM36 set at .1 nT. Survey transects were spaced at .5-m intervals,
resulting in 16 data values per m2. In the images, the magnetic data are shown
in gray tones. The small black areas are positive magnetic anomalies. In the
interpretation image, the white line shows the limits of mechanized stripping
of the plow zone. Structures are shown as red rectangles and the small yellow
circles are pits. One can see that many of the magnetic anomalies turned out
to be associated with pits. Magnetic anomalies suggest that additional pits
are located in the central portion of the survey area where no excavation occurred.