-- [ From: Linda Derry * EMC.Ver #2.5.03 ] --
 
 
A recent message from Mike Friends spoke about a contamination problem from Foss
il carbon contamination.  As a historical archaeologist I seldom work with C14,
but my perspective (I think) brought an insight to contamination on my site and
perhaps to other sites that were occupied into the 19th century.  Under the rema
ins of Cahawba (a Southern 19th century town), we found a late Mississippian Ind
ian Village.  All the local experts thought this occupation dated to the 16th ce
ntury but the carbon 14 dates were coming in much earlier.  I found that the his
torical documents from the 19th century town offered a possible explaination.  T
he town's newspaper often talked about the townspeople spreading lime on their y
ards.  this apparently was a common practice and and was  thought to be  healthf
ul (and helped to keep the smell down!).  Would not the regular spreading of lim
e and its perculation downward, create contamination of C14 samples and push the
 dated backward in time?  This is probably a wide spread problem
, since many sites are occuppied and reoccuppied for centuries.
 
Linda Derry
Alabama Historical Commission [log in to unmask]