Comaum NFRs - ForestrySA

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dune ranges were eroded and younger dunes deposited on them; two sequences
remain on the East Naracoorte range and four have been recognised on the West
Naracoorte range. The dune limestone exposed on the higher points in Wombat Flat
NFR is likely to be from mid-Pleistocene dune remnants. Geologically, most of the
soil cover is derived from leached siliceous sands of the Malanganee Formation. In
Victoria these have been classified as Kowree sand or Richmond sand. Rendzina
swamp soils occur where calcarenite forms the base of depressions.
Minor occurrences of terra rossa soils derived from calcarenite dune limestone are
present in the eastern part of Wombat Flat NFR.
Comaum NFR and Boolara NFR are situated on the West Naracoorte Range system,
deposited close to the margin of the downthrown side of the Kanawinka Fault which
indicates the oldest Pleistocene deposits are around 685 000 years old. Both
reserves have a core structure of calcarenite dune limestone, with a general
elevation of 70-75 and high points up to 90m. Soils have been formed mainly from
aeolian siliceous dune sands. Relatively small areas of terra rossa are present on
dune crests.
Comaum NFR is located on the eastern boundary of an area displaying karst
features including runaway holes (dolines and cenotes). Boolara NFR is in a region
denoted as lacking karst features although still traversed by the West Naracoorte
range, rather than direct contact with Mt Gambier limestone to the north and west.
(Boardman, R 1999).
2.2.3 Soils
Soil surveys prior to purchasing Comaum and Boolara NFRs described six soil types.
Swamp Soil has been formed in an enclosed sandy depression in Compartment A
Wombat Flat NFR. This soil is shallow over limestone, dark grey to black with a high
organic content. Surface water has not been observed in this swamp for over 20
years, the last record of short term flooding being in the late 1950s.
Meadow Podsol, a shallow dark grey or brown surface sand with abundant coarse
pink grains, over clay, occurs on flats subject to seasonal waterlogging in normal
rainfall years.
Humus Podsol, described as shallow brown sands over clay occurs on flats which
may be subject to seasonal water logging or inundation.
Normal Podsol, (a) described as yellow sands with varying depth to clay according to
their elevation on the dune have developed on sites with good drainage.
(b) described as deep grey sands on the dune crests and upper slopes.
Terra rossa, loams and loamy sand transitionals derived from exposed or shallow
calcarenite limestone are limited in extent on some dune crests and upper slopes.
The dune sands on these Reserves have a larger grain size contributing to a more
loose surface than the sands further south. Sand track access during most of the
year is difficult due to the dry unconsolidated nature of the sand.
2.2.4 Hydrology
Final Plan – August 2001