Direct dating of the construction of ancient earthworks in eastern Nor
th America is needed to resolve the ambiguity surrounding more indirec
t methods such as radiocarbon. Sediment dating by luminescence can pot
entially fill this need. Luminescence dating of buried surface sedimen
ts from earthworks at two sites in northeastern Louisiana show that th
e mound and/or ridge sediments were not well exposed to light at the t
ime of their construction or occupation. Nevertheless the structure of
the luminescence data allows an evaluation of the age of construction
at both sites and demonstrates that earthwork building occurred much
earlier than was previously believed. (C) 1997 Elsevier Science Ltd.