Chemistry Reference
In-Depth Information
Bogs.
A particular type of soil which has received frequent attention in
archaeological studies, particularly in northern Europe, is that of
bogs
, water-
logged areas that have a spongy consistency. The solid component of most
bogs is
peat
, a very dark, unconsolidated, partially decomposed and car-
bonized mass of plant remains in which, usually, very low pH values and
anaerobic conditions prevail. Some bogs include as little as 2% peat; the
remaining 98% is water. In others, the peat may constitute as much as 15%
by weight of the bog. The low pH and the anaerobic conditions inhibit the
development of spoilage microorganisms. Buried under such conditions the
remains of dead organisms may become naturally mummified and remain
in a good state of preservation, often lasting for extended periods of time.
The prevailing acidity also causes
decalcification
(dissolution of the calcium)
as well as removal of most of the inorganic components of the bones; this
becomes apparent when human and/or animal mummies with soft, yield-
ing bones are removed from bogs (see Chapter 15) (van der Sanden 1996;
Brothwell 1987).
