Red Gum Native Forest Reserves - ForestrySA

2.2.2 Local Geology
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Muddy Flat NFR is situated on the seaward margin of the Mid-Pleistocene Penola
Bay over which control was exerted by the southern extension of the youngest
element of the west Naracoorte Dune complex, which lies close by, to the east. The
Reserve has shallow acid, siliceous sand sheets deposited over a reworked Gambier
Limestone base. Lunette swamps have been attributed to lime solution features in
the underlying sediments, as a mild form of karst feature. The lunettes have fen-like
vegetation associated with the calcareous nature of ground.
Round Waterhole NFR is associated with the Penola Bay shores and wind dispersal
of predominantly siliceous sands to leeward by the predominant west and south-west
winds. These sands have been deposited as irregular low dunes and the curve of
the bay is reflected mostly by linear swamps of dominant swales. The sands thinly
overlie clayey lagoon deposits which may be exposed in lower, swampy patches.
The area has probably been strongly deflated following marine incursions which
probably date from 330,000 years BP, in East Avenue range times. Sub-aerial
leaching, winnowing and deflation have occurred into Holocene times and have been
recognised as the Tooloy Land Unit of the Follet land System. (Boardman, R. 1992).
2.2.3 Soils
There have been no recent formal soil surveys in these Reserves.
Observations by Forester R H Davey in 1944 in and surrounding the Round
Waterhole NFR, Stephens’ broad scale survey in 1937-1940, and adjacent pine
plantation soil surveys suggest five soil types as described by Stephens (1941)
including variants and transitionals are present.
Swamp Soils - formed in shallow enclosed depressions and are moderately organic
overlying greyish or bluish clays.
Kalangadoo Sand - a meadow podsol occupies large areas of the sand flats some
times as a transitional with Wandilo Sand and may be subject to seasonal water
logging or inundation.
Wandilo Sand – a humus podsol with clay at a relatively shallow depth occurs on the
flats, in some situations as a transitional with Swamp Soil, and may be subject to
seasonal water logging or inundation.
Nangwarry Sand - a normal podsol with varying depth to clay occurs on the low
rises with better drainage.
Terra rossa Soils - a sandy loam derived from limestone parent material is present
as a minor occurrence at Muddy Flat NFR only.
Final Plan – February 2001