BUREAU OF GEOLOGY


which are situated on limestone bedrock. The trees, which are responsi-
ble for the peat beneath them, contain enormous amounts of lignin.
Lignin is very resistant to decay (Moore and Bellamy, 1974). It is alterna-
tively suggested that hammock peats in Florida may be controlled more
by the persistence of water than by the amount of lignin (A. Cohen,
personal communication, 1984).

 THE ACCUMULATION OF PEAT IN FLORIDA

 by
 Paulette Bond

 Rates of Peat Accumulation

 Knowledge of the rate of peat accumulation is important in that it
allows various extractive uses for the resource to be weighed in light of
the amount of time it takes for the mineral to accumulate. Rates of peat
accumulation are usually determined using the carbon-14 method of dat-
ing organic materials. This method is subject to a number of difficulties
when applied to peat. The following problems were enumerated by
Moore and Bellamy (1974): 1) Wide errors may be introduced since
young roots may penetrate material at depth. This problem could result in
apparently rapid rates for the accumulation of peat. 2) Older layers are
compacted as new ones are deposited. This could cause rates of deposi-
tion to appear anomalously low. 3) Rates of peat formation vary with
climate and climate varies with time. Thus, an accumulation rate proba-
bly reflects a sort of average rate for some given amount of peat. Several
estimates of peat accumulation rates in Florida are presented in Table 1.
 The variation in rate presented here for peat accumulation may be
attributed to a number of factors. Gleason, et al., (1974) used Davis'
(1946) data to compute a value of productivity for the sawgrass environ-
ment. Productivity refers to the amount of dry organic matter (measured
in pounds) which is formed on an acre of ground in a year. When this
productivity is compared to the dry weight of an acre-foot of peat as
estimated by Davis (1946), a discrepancy is apparent. According to
these computations, more material accumulates as peat than is originally
formed in the sawgrass environment (Gleason, et al., 1974). Factors
which may account for this difficulty include possible low estimates of
productivity and inadequate estimates of silica content or peat density. It
is also possible that silica in the peat might not be entirely derived from
sawgrass (Gleason, et al., 1974). Rates of peat accumulation computed
from radiocarbon age are grouped about an average of 9.1 cm/100
years. The rate of peat accumulation can vary with climate (which also
varies with time), the position of the water table and nutrient supply
(Moore and Bellamy, 1974). Data are not available which would allow
rate variation in different environments to be evaluated. The rates pre-
sented here were calculated from peats produced from varying plant