Semeniuk & Semeniuk: Wetland sedimentary fill - particles, sediments, classification 
Table 1 
Particle types in wetland sediments 
mud-size particles (< 63 pm in size) 
organic mud-sized particles < 63 pm, and mostly < 4 pm in size; 
microcharcoal < 63 pm in size; 
carbonate mud particles (calcite, Mg-calcite, aragonite, dolomite), < 63 pm in size, mostly < 4 pm in size, as comminuted shell, 
intraclasts, and charophytes, single crystals, and undifferentiated types; 
quartz silt particles, < 63 pm in size; 
phytoliths as silt-sized and clay-sized siliceous particles, < 63 pm in size; 
diatom as silt-sized and clay-sized particles, < 63 pm in size; 
sponge spicule fragments, < 63 pm in size; 
phyllosilicate mineral particles (kaolin, montmorillonite, white mica), < 63 pm in size, mostly < 4 pm in size; 
goethite mud, < 4 pm in size; 
feldspar silt, < 63 pm in size; 
heavy minerals ( e.g ., haematite, rutile), < 63 pm in size (mainly silt). 
sand-size particles (63 pm - 2000 pm in size) 
quartz sand, mostly 125 pm to 1000 pm in size; 
carbonate intraclast sand, mostly 125 pm to 2000 pm in size; 
sponge spicules, mostly 100 pm to 300 pm in size; 
diatom intraclast sand, mostly 125 pm to 2000 pm in size; 
peat clast sand, mostly 125 pm to 2000 pm in size; 
microcharcoal and charcoal 63 pm to 2000 pm in size; 
carbonate shell-fragment sand, mostly 125 pm to 2000 pm in size; 
heavy minerals (e.g., haematite, rutile), mostly 63-125 pm in size; 
gypsum crystals as single crystals and rosettes, mostly 63-250 pm in size. 
gravel-sized particles (> 2000 pm in size) 
carbonate intraclast gravel particles, > 2000 pm in size; 
carbonate shell (gastropod) gravel, > 2000 pm in size; 
diatom intraclast gravel, > 2000 pm in size; 
peat intraclast gravel, > 2000 pm in size; 
charcoal > 2000 pm in size. 
Vegetation material 
plant fibres, detritus, leaves, flowers, fruit, twigs, branches and trunks 
"mud-sized phyllosilicate minerals" or as "mud-sized 
phyllosilicate mineral particles" to circumvent the issue 
that these "clay minerals" can range from clay-sized to 
silt-sized. Sediments composed dominantly of kaolinite 
are termed "kaolinitic mud" since there will be clay-sized 
and silt-sized kaolinite therein. 
The main sedimentary particles and sedimentary 
components that constitute wetland sedimentary fill are 
shown in Table 1. The methods of identifying these 
sedimentary constituents in wetland sediments in this 
study are summarised in Table 2. 
Current terms for wetland sediment types formed from 
the common particles 
In the literature, there are a number of terms that 
apply to deposits formed in wetlands that are relevant to 
the particle types encountered in this study, viz., those 
composed of organic (plant) matter, diatom remains, 
sponge material, fine-grained carbonate mud, or water 
saturated sand. Sediments composed of organic matter, 
mostly as decayed plant material, have been termed 
organic mud or organic ooze, sapropel to saprocol, and 
peat. The terms "organic mud", "organic ooze", "muck", 
or "gyttja" could be applied generally to deposits that are 
mud-sized and composed of organic carbon and decayed 
plant remains, but are more relevant to the immediate 
surface layers of organic deposits in wetlands where 
sediments have a degree of thixotrophy than to the more 
consolidated deposits at shallow to moderate depths. 
"Sapropel" is a term for unconsolidated jelly-like ooze or 
sludge composed of plant remains macerating and 
putrefying on the shallow bottoms of lakes and seas, and 
"saprocol" refers to an indurated sapropel (Jackson 1997). 
The terms are part of a sapropelitic series that reflect 
increasing consolidation into coal (viz., sapropel, as 
organic ooze, saprocol, as indurated sapropel, and 
saprodil, as sapropelitic coal of Tertiary age, saprodite, 
and so on). In the soil literature, materials composed of 
accumulated organic matter (or peat) are referred to as 
"histosols", an order of soils (USDA 1975; FitzPatrick 
1983), with further subdivision into suborders based 
either on the degree of decomposition, e.g., "fibrist" (the 
least decomposed), "hemist" and "saprist" (the most 
decomposed), with the extent of decomposition assessed 
by the content of plant fibre (Soil Survey Staff 1998), or 
on moisture content. In the Earth Sciences, 
unconsolidated deposits of semi-carbonized plant 
remains in a water-saturated environment are referred to 
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