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Acknowledgements

Geomorphic features on the Australian continental margin: implications for regional marine planning. Peter Harris, Andrew Heap, Vicki Passlow, Laura Sbaffi, Mellissa Fellows, Rick Smith, Cameron Buchanan and James Daniell Geoscience Australia Petroleum & Marine Division GPO Box 378

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Acknowledgements

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  1. Geomorphic features on the Australian continental margin: implications for regional marine planning Peter Harris, Andrew Heap, Vicki Passlow, Laura Sbaffi, Mellissa Fellows, Rick Smith, Cameron Buchanan and James Daniell Geoscience Australia Petroleum & Marine Division GPO Box 378 Canberra ACT 2601

  2. Acknowledgements • Funding provided by the National Oceans Office • Suggestions and assistance from: Neville Exon, Peter Hill, Jim Colwell and Phil Symonds

  3. What does the government need us to do and why? • A key goal of Regional Marine Planning is to protect and maintain biodiversity • Biological data are scarce  the regionalisation process relies on proxies (surrogates) • Benthic habitat maps are a proxy for biodiversity • Useful to map habitat diversity • Geomorphic features = habitat types (broad scale)

  4. Geoscience Australia activities 2001-03 • Sediment mapping (grain size, CaCO3)  MARS data compilation • GEOMAT sediment mobility modelling (waves and tidal currents) • Preliminary studies of statistical relationships between sediment type, energy regime, fossil content and biota • Field work (cruises to Torres Strait 2002, Gulf of Carpentaria next month) • Seabed geomorphology mapping (from bathymetry database plus swath surveys, LADS, satellite imagery, etc.)

  5. Database Construction of new bathymetry database adding RAN chart fairsheet data, swath surveys and ship tracks 87 million points added making 289 million points, Generation of new 250 m grid covering Australian EEZ (8.6 million km2) Interpretation Mapping of geomorphic features based on 21 categories Hand drawn maps, digitised, attributed and stored in GIS Analysis of features in terms of relative areas. Geomorphic Features Project OutlineProject started August 2002, scheduled completion June 2003.

  6. Goal is to map features in entire EEZ, but only the SE region is completed as of today (2nd May). Bathymetric data coverage around Australia.

  7. General principals: features mapped at scale of 1:5,000,000. Minimum scale of feature mapped is around 10 km. Features mapped by previous workers were included (based on literature survey). Features mapped on best available data - BUT - not all features can be mapped due to data limitations.

  8. List of geomorphic featuresbased on terms adopted by the International Hydrographic Organisation (IHO)

  9. Bass Canyon, eastern Bass Strait • Submarine canyons can be further subdivided based on: • Extend onto the shelf (yes/no) • Associated with onshore fluvial system (yes/no) • Debouch onto abyssal plain (yes/no) • Single or with tributaries (yes/no)

  10. Mapping of submarine canyons aided by drainage analysis

  11. Sill Bank Shelf basin Sand banks Shelf valleys Outer shelf Terraces

  12. Dunes and tidal current ridges Banks Strait, NE Tasmania

  13. Selection of broad areas of interest (BAOIs), candidate areas for marine protected areas (MPA’s). BAOI’s should include the full range of geomorphic features occurring in a region. Underlying philosophy is that that if full range of geomorphic features are included in MPA’s then they will be representative of the regional biodiversity. Caveats: We know that some geomorphic features are associated with certain assemblages of biota (eg. reefs, seamounts), but we don’t know what the association is for every type feature (or if the association is unique to one or other features). Application:

  14. BAOI’s selected for the SE region.

  15. Conclusions 1. Geomorphic features are first-order elements useful for bioregionalisations at scale of continental margins 2. Geomorphic features have physical and biological associations (eg. reefs and biota, bedforms and current regime, etc.), but... 3. More research work is needed to establish links between specific biotic assemblages and features as well as establishing what level of detail is needed for feature classification to maximise relevance to biota (eg. 30 IHO types versus 21 used in this study).

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