Journal of the Royal Society of Western Australia, 87(4), December 2004 
Table 2 
Method of identification of particle types 
Mud-size particles 
(< 63 pm in size) 
Method of identification 
organic mud-sized particles 
carbonate mud particles 
quartz silt particles 
sponge spicule fragments 
phytoliths 
diatom silt and clay particles 
phyllosilicate mineral particles 
goethite mud 
feldspar silt 
microcharcoal 
dealing only with the < 63 pm size class separated by sieving: 
combustion for organic matter; SEM and EDS; 
acid-digestion, and XRD, SEM and EDS for carbonate particles; 
SEM and EDS and light microscopy for diatoms and types of 
carbonate mud particles; XRD and EDS for phyllosilicate mineral 
particles, goethite mud and feldspar silt; 
high resolution petrographic microscopy for plant remains, 
quartz, phyllosilicate mineral particles, diatoms, phytoliths, 
carbonate particles, and sponge spicules. 
Sand-size particles 
(63 pm - 2000 pm in size) 
quartz sand binocular microscopy and petrographic microscopy for the quartz sand 
sponge spicules and gypsum, sponge spicules, and carbonate sand types; binocular 
carbonate intraclast sand microscopy for the peat clasts. 
peat intraclast sand 
carbonate shell-fragment sand 
microcharcoal and charcoal 
gypsum crystals 
Gravel-sized particles 
(> 2000 pm in size) 
carbonate intraclast gravel 
carbonate shell (gastropod) gravel 
diatom intraclast gravel 
peat intraclast gravel 
charcoal 
binocular microscopy for the peat, diatomite, and carbonate clasts; 
light microscopy for diatoms within clasts. 
Vegetation material 
plant fibres, detritus, leaves, flowers, 
fruit, roots, rhizomes, culms, twigs, 
branches and trunks 
visual inspection on excavation faces, and sieve residues, and 
binocular microscopy. 
as "peat" (Jackson 1997). Teakle & Southern (1937) use 
two terms to refer to deposits (or "soils") of organic 
material: peat, and muck. Following Dachnowski (1920), 
Teakle & Southern (1937) recognised three main groups 
of peaty material: sedimentary or pulpy peat, fibrous 
peat, and woody peat. For purposes of this paper, the 
single term "peat" will be used for surface and 
subsurface sedimentary deposits composed of plant 
debris, plant detritus, and organic matter, in that it is a 
term that encompasses organic deposits that range from 
"ooze" to semi-consolidated material in the sense of 
Clymo (1983), and with varying structure, fabric and 
texture (from structureless, laminated, root-structured, to 
bioturbated, and from fibrous to massive). 
Sediments composed mainly of diatoms and their 
fragments are "diatomite", which is synonymous with 
the term "diatomaceous earth" (Jackson 1997). The term 
"diatomaceous earth" carries with it a connotation of the 
sediment being porous (the result of interstitial porosity 
developed by platey diatom grains in randomised array 
in a grain-support framework, as well as intrafrustule 
porosity), and having low bulk density. It is this 
interstitial and intrafrustule porosity within 
"diatomaceous earth" that renders it useful as a filter for 
industrial and domestic purposes. However, as will be 
described later, diatoms comprising wetland sediments 
range from whole to totally fragmented frustules, and as 
a result, diatomaceous sediments can vary from those 
with properties close to "diatomaceous earth," to those 
composed of closely packed fine-grained silica fragments 
(giving broad XRD peaks typical of diatoms) with the 
sediment having the properties and bulk density of 
quartz silt. Given this range of sediment particle 
possibilities, the term preferred in this paper is 
"diatomite". 
Sediments composed mainly of sponge spicules and 
fragments are "spongolites" (Jackson 1997). Spongolitic is 
used herein to refer to wetland sediments with moderate 
amounts of sponge spicules. There is no current term for 
sediments composed dominantly of phytoliths, and in 
this study phytoliths were not of sufficient abundance to 
warrant coining a lithologic term to cover this category. 
Phytolithic is used herein to refer to wetland sediments 
with moderate amounts of phytoliths and fragments. 
Sediments composed of fine-grained mud-sized 
calcium carbonate particles have been termed "carbonate 
148 
