Sea-Level History, 45,000 to 30,000 yr B.P., Inferred from Benthic Foraminifera, Gulf St. Vincent, South Australia

Abstract

Surficial sediments of Gulf St. Vincent, South Australia, are predominantly bioclastic, cool-temperate carbonates. Benthic foraminifera are abundant and distribution of species is closely related to water depth. For example, Massilina milletti is most common at depths ca. 40 m, while Discorbis dimidiatus is characteristics of shallow, subtidal environments. Elphidium crispum, a shallow-water species, and E. macelliforme, favoring deeper water, provide a useful numerical ratio. Their logarithmic relative abundance, in the sediment size fraction 0.50–0.25 mm, correlates strongly with water depth. Vibrocores SV 4 and SV 5 recovered undisturbed sections of Quaternary strata from the deepest part (ca. 40 m) of Gulf St. Vincent. Amino acid racemization and radiocarbon age determinations show that late Pleistocene sections of the cores were deposited over the time ca. 45,000 to 30,000 yr B.P. Species of fossil foraminifera, recovered from these sections, are mostly extant in modern Gulf St. Vincent, thus allowing paleoecological inferences of late Pleistocene sea levels. These inferred sea-level maxima can be correlated with those determined from study of Huon Peninsula coral reef terraces. Initial estimates of tectonically corrected sea levels for transgressions in Gulf St. Vincent at 40,000 and 31,000 yr B.P. are −22.5 m and −22 m, respectively. The intervening regression lowered sea level to −28 m.

Late Quaternary terrigenous sediments from the Murray Canyons area, offshore South Australia and their implications for sea level change, palaeoclimate and palaeodrainage of the Murray–Darling Basin

“…To achieve these shifts, sea level must have been in the sensitive depth range of À40 to À70 m, as found by Lambeck and Chappell (2001) in their global sea level curve for these periods. Sea level fluctuations of only À16 to À30 m were published from investigations in Gulf St. Vincent (Cann et al, 1988(Cann et al, , 1993(Cann et al, , 2000a. Fluctuations in that depth range would have had hardly any effect on the position of the mouth of the bPalaeo-MurrayQ and could not explain the amplitude in the variation of our fluvial proxies smectite, clay/silt-and quartz/ feldspar-ratio.…”

Variation in the Eucalyptus globulus Complex Revisited

“…Bathymetry (AUS CHART 422) indicates that two disjunct land connections may have provided opportunities for this migration, one across eastern Bass Strait from north-east Tasmania through the Furneaux Group to South Gippsland east of Wilsons Promontory, and another from north-westem Tasmania through King Island to the Otway Ranges near Lome (g10) and also to South Gippsland west of Phillip Island (g12). The eastern connection almost certainly existed more or less continuously from 40 ka to about 10 ka (Cann et al 1988) and during the numerous previous glacials (Shackleton and Opdyke 1973) with connections through the western route being less frequent and of shorter duration (e.g. Blom 1988).…”

“…Migration of phenotypes between Victoria and Tasmania has undoubtedly occurred, and is likely to have been related to the sporadic occurrence of land bridges between Tasmania and Victoria coinciding with large climatic changes (Shackleton and Opdyke 1973;Cann et al 1988). Bathymetry (AUS CHART 422) indicates that two disjunct land connections may have provided opportunities for this migration, one across eastern Bass Strait from north-east Tasmania through the Furneaux Group to South Gippsland east of Wilsons Promontory, and another from north-westem Tasmania through King Island to the Otway Ranges near Lome (g10) and also to South Gippsland west of Phillip Island (g12).…”

Revisiting marine isotope stage 3 and 5a (MIS3–5a) sea levels within the northwestern Gulf of Mexico

“…Based on the elevation of the erosional truncation of seismic reflections, Suter et al (1987) provide inference for MIS3 sea levels in Louisiana as high as −20 m. Based on the analysis of the paleo-ecology of foraminifera within multiple cores within the northeastern Gulf of Mexico, Fillon et al (2004) argue for sea levels around −35 m during MIS3. Records from other locations around the world including South Australia (Cann et al, 1988(Cann et al, , 2000Murray-Wallace et al, 1993), Italy (Mauz and Hassler, 2000), and Japan (Kuwabara et al, 1999) suggest that the Gulf of Mexico was not the only margin that may have experienced elevated MIS3 sea levels. Records from the South Australian shelf place MIS3 sea levels between −22 and −29 m bsl based on amino acid racemization of mollusks within a shallowmarine carbonate succession (Cann et al, 1988;Cann et al, 2000;Murray-Wallace et al, 1993).…”

“…Records from other locations around the world including South Australia (Cann et al, 1988(Cann et al, , 2000Murray-Wallace et al, 1993), Italy (Mauz and Hassler, 2000), and Japan (Kuwabara et al, 1999) suggest that the Gulf of Mexico was not the only margin that may have experienced elevated MIS3 sea levels. Records from the South Australian shelf place MIS3 sea levels between −22 and −29 m bsl based on amino acid racemization of mollusks within a shallowmarine carbonate succession (Cann et al, 1988;Cann et al, 2000;Murray-Wallace et al, 1993). Records from estuarine deposits within uplifted terraces and bound by tephra deposits of known ages along the Boso Peninsula of Japan suggest Stage 3 sea-level elevations of −22 to −34 m bsl (Kuwabara et al, 1999).…”