|
| << vorige | volgende >> |
Tijdschrift beschrijving
Alle jaargangen van het bijbehorende tijdschrift
Alle afleveringen van het bijbehorende jaargang
Alle artikelen van de bijbehorende aflevering
Details van artikel 18 van 20 gevonden artikelen
| Titel: |
The Pleistocene terrestrial carbonate mantle on the southeastern margin of the St Vincent Basin, South Australia |
| Auteur: |
Phillips, S. E. Milnes, A. R. |
| Verschenen in: |
Australian journal of earth sciences |
| Paginering: | Jaargang 35 (1988) nr. 4 pagina's 463-481 |
| Jaar: |
1988-12 |
| Inhoud: |
An extensive blanket of calcareous sediment and associated calcrete mantles Pleistocene non-marine sediments in the St Vincent Basin. The nature of the carbonate mantle and its relationships with underlying sediments assigned to the Ngaltinga Formation have been studied in the Noarlunga and Willunga Embayments along the southeastern margin of the basin. The Ngaltinga Formation is comprised of clay-rich sediments with channel sands and occasional gravels interpreted to be of fluvial origin. The clay-rich sediments may represent flood-basin or overbank deposits. Carbonate beds are present at intervals through the formation, especially within sands immediately below the carbonate mantle in the northern part of the Noarlunga Embayment. The form and mineralogical composition of these beds suggest they are the carbonate accumulation horizons of former soils or palaeosols. The carbonate mantle is interpreted as a complex sedimentary and pedogenic unit. The primary sediment contained both calcite and dolomite, was characterized by a high silt and clay content, and is believed to have been largely of aeolian origin. Systematic changes in the form of the carbonate materials down the profile through the mantle are also reflected in changes in mineralogical composition from calcite-rich materials at the top to dolomite-rich materials at the base and are considered to reflect pedogenic processes. Marked lateral changes in facies or forms of calcrete from thick, indurated pans to zones of accumulated nodules and pisoliths appear to be a response to local geomorphic influences. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 18 van 20 gevonden artikelen
| << vorige | volgende >> |