School of Geography - Theses

Permanent URI for this collection

http://hdl.handle.net/11343/208041

Filters

2000 1
1
1
Reset filters

Settings
Statistics
Citations
End date: 2001 × Start date: 2000 × Subject: Anderson Inlet (Vic.) × Subject: Victoria ×

Search Results

Now showing 1 - 1 of 1
  • Item
    Thumbnail Image
    Holocene sea levels and related environmental changes in Anderson Inlet, Victoria, Australia
    Li, Longyin ( 2000)
    Anderson Inlet in south eastern Australia preserves marine sediments that were deposited facing the Southern Ocean during the Holocene. Data obtained from near surface sediment samples together with topographic data are used to investigate the geomorphology, stratigraphy, Holocene sea level changes and related physical environment in Anderson Inlet, Victoria, Australia. The Holocene strata in the Anderson Inlet area in Victoria can be stratigraphically divided into four units, Unit I, Unit II, Unit HI, and Unit IV. Unit I and Unit IV lack fossils and were deposited in non-marine, probably fluvial, environments. Unit E and Unit IE contain abundant foraminifers with molluscs, ostracods and bryozoans. Foraminiferal analysis suggests that Unit IE was deposited in a partially sheltered marine environment, while the high plankton content and relatively high diversity of benthic species in Unit E indicate that this unit was deposited in an open bay at water depths possibly less than 5 m. The faunal data are integrated with radiocarbon dates to arrive at the following Holocene palaeoenvironmental history in this area: 1. Low alluvial plain stage (10000-7000 yr BP); 2. Open bay environment stage (7000-5500 yr BP); 3. Partially sheltered marine environment stage (5500-4500 yr BP); 4. Alluvial plain and coastal lagoon environment stage (since about 4500 yr BP). Contrary to interpretations made elsewhere in south eastern Australia, evidence exists for multiple higher Holocene sea levels in this area. Evidence for two higher Holocene sea level events with one lower sea level event in between has been identified. The timing of these Holocene sea level fluctuations correlates with the deglaciation history of Antarctica and climatic changes inferred from the geological record of mountain glaciers and fossil plants. The evidence suggests that the Anderson Inlet area has been strongly influenced by cold water regimes from the Southern Ocean during the middle Holocene and that marked environmental changes have occurred in the area during the Holocene, associated with the sea level fluctuations. During the last interglacial when sea level was 6.55 m higher than present, the Anderson Inlet area was an open marine environment consisting of several smaller embayments. The shoreline during this time followed the coastal cliffs and bluffs. During the first higher Holocene sea level stage (ca.7000-6000 yr B.P.), sea level was 1.8 m higher than present, the area was also an open marine embayment. During the second higher Holocene sea level stage (ca.5500-4500 yr B.P.) when sea level was 0.5 m higher than present, a minor sand spit developed which partially restricted the marine * embayment. It is inferred that the higher sea levels are likely to have been eustatic events associated with the deglaciation of Antarctica during the Holocene. The modem barrier system of Anderson Inlet is made up of a complex of sand dunes built up in response to the Holocene sea level fluctuations, especially during regressive events since the middle Holocene. The sand dune system of Anderson Inlet is very similar to other coastal barrier systems in south eastern Australia that have built up during the Holocene.