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| Titel: |
Provenance of microfossils in aeolian calcarenites and calcretes in southern South Australia |
| Auteur: |
Milnes, A. R. Ludbrook, N. H. |
| Verschenen in: |
Australian journal of earth sciences |
| Paginering: | Jaargang 33 (1986) nr. 2 pagina's 145-159 |
| Jaar: |
1986-06 |
| Inhoud: |
Thin-section studies of previously assumed Pleistocene bioclastic dune calcarenites in the coastal regions of southwestern South Australia reveal a reworked marine microfossil assemblage which appears to have been derived mostly from sediments of Miocene age. Calcretes associated with the calcarenite sequence and aeolian carbonate sediments in inland regions of Eyre Peninsula contain a similar microfossil assemblage, though the microfossil clasts are extensively reworked and recrystallized. None of the samples examined carried microfaunas characteristic of Quaternary sediments such as the Glanville and St Kilda Formations. It is possible that deposition of the dune calcarenites commenced after regression of the Middle Miocene seas which had left a widespread blanket of marine sediments over southern South Australia. In this regard the complete sequence of dune calcarenites may span a longer time period than the Bridgewater Formation. It is likely that continued deposition of dune calcarenites through the Pliocene and Pleistocene either modified earlier dune ridge configurations (in tectonically stable regions such as Eyre Peninsula) or created new ridge systems (in regions of tectonic instability such as southeastern South Australia). Concomitant aeolian reworking of the former coastal dunes produced the extensive inland blankets of carbonate sediments and calcretes, though lacustrine and pedogenic sources of carbonate and calcareous bedrock were locally important. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 6 van 12 gevonden artikelen
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