CONTROLS ON THE CHEMICAL VARIABILITY OF PEAT TYPES IN A DOMED PEAT DEPOSIT, BARAM RIVER AREA, SARAWAK, MALAYSIA

Pyrolysis GC/FT-IR/FID and pyrolysis GC/MS studies have been conducted on peat samples from the margin and central portions of a tropical domed peat deposit in the Baram River area, Sarawak, Malaysia, in order to determine the chemical variability of peat types found within the deposit. In an effort to "unmix" the chemical variability of the samples, an EXTENDED QMODEL program was utilized which produced a series of 4 end members. These end members, composed of various proportions of each of the 49 pyrolysis products monitored in this study, are combined in various proportions in various proportions to reproduce the composition of each of the 32 samples. Comparison of the chemical data with previous petrographic and megascopic analysis reveals parallel trends between the input from the end members and the makeup and degree of degradation of each of the peat types. From this analysis, it can be concluded that the 4 end members produced in this analysis represent input from (a) guaiacyl lignins, (b) lignin biodegradation products, (c) cellulosic derived products, and (d) syringyl lignins. The inputs from the 4 end members can be traced to the type of plants and the degree of degradation. In addition, comparison of the spatial distribution of the 4 end members reveals that the samples in the central portion of the deposit have much more chemical variability than the highly degraded samples on the margin of the deposit.