. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 116 ANNALS OF THE SOUTH AFRICAN MUSEUM Aeolianite consists of consolidated beach and dune sands distinct from currently forming beach rock. Most aeolianite deposits are of considerable thickness, exhibit pronounced cross-bedding and are Pleistocence to Holocene in age. Being largely backshore deposits, they mark former strandlines. The beach and dune sands have been consolidated to varying degrees by calcium carbonate. Lithification therefore implies a considerable amount of calcium carbonate grains
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 116 ANNALS OF THE SOUTH AFRICAN MUSEUM Aeolianite consists of consolidated beach and dune sands distinct from currently forming beach rock. Most aeolianite deposits are of considerable thickness, exhibit pronounced cross-bedding and are Pleistocence to Holocene in age. Being largely backshore deposits, they mark former strandlines. The beach and dune sands have been consolidated to varying degrees by calcium carbonate. Lithification therefore implies a considerable amount of calcium carbonate grains or comminuted shells in the original sands, a long period of leaching to cement the core material with concomitant formation of overlying dominantly quartzose sands. The current absence of the latter in association with the aeolianite further implies that the aeolianite deposits must now be considerably diminished in volume. Where several phases of aeolianite deposi- tion have occurred, it is likely that the leached overlying sands have been incorporated into the later deposits. The degree of lithification depends partly on age but also apparently on exposure. Thus resistant aeolianite frequently outcrops along eroding cliffs and on the present beach, lithification being asso- ciated with spray wetting. AEOLIANITE DISTRIBUTION Australian aeolianite deposits are widely distributed along the south- eastern coasts from Westernport Bay, on the Bass Strait islands and northern Tasmania to Eyre Peninsula. The red silicious dunes of the east coast are, however, very different and they contain no aeolianite core (Bird, E. C. F. & Thorn, B. pers. comm.). Aeolianite deposits are also found along the western coast between Cape Leewin and North West Cape where they rest on the Coastal Limestones, in origin also aeolianite (Fig. 1). Aeolianite is also widespread along the South African coastline between Saldanha Bay and East London. More recently the red sands of the coastal fringe betw
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
