The Tasmanian Geoconservation Database (TGD) is a source of information about geodiversity features, systems and processes of conservation significance in the State of Tasmania.
The database is a resource for anyone with an interest in conservation and the environment. However, the principal aim is to make information on sites of geoconservation significance available to land managers, in order to assist them manage these values.
Being aware of a listed site can assist parties involved in works or developments to plan their activities. This may involve measures to avoid, minimise or mitigate impacts to geoconservation values.
More than a thousand sites are currently listed. These range in scale from individual rock outcrops and cuttings that expose important geological sections, to landscape-scale features that illustrate the diversity of Tasmania's geomorphic features and processes. Many of the sites are very robust and unlikely to be affected by human activities; others are highly sensitive to disturbance and require careful management. (See information on
significance and potential threats.)
Accessing the Database
The TGD is available on the web, where it can be searched as a map-based tool via the Tasmanian Government's LIST and Natural Values Atlas websites.
The TGD can be accessed in two ways: 1. On the LIST
The TGD is a layer on the LIST.
1. Go to the LIST
www.thelist.tas.gov.au 2. Click
LISTmap 3. Click 'Layers' (top right) and then 'Add Layer'
4. Scroll down to 'Geology and Soils', then under 'Geoscientific information' select 'Geoconservation Sites'
5. Click on the green button to add layer to map
6. Close the 'manage layers' dialog box
7. Zoom to area of interest - note that most sites are only displayed at a scalelarger than approximately 1:250 000
8. Click on a feature for basic information
2. On the Natural Values Atlas
The Natural Values Atlas provides easy-to-use web access into comprehensive natural values information, including the Tasmanian Geoconservation Database.
Go to
www.naturalvaluesatlas.tas.gov.au and see the
Register section to download an Access Form to register and submit to request access to the site (this is a quick, automated process). When access is granted click on the Geodiversity tab then Geosite Search. NVA geosites may then be searched for according to a range of text attributes. Click 'Advanced Search' to see more options. Click 'Search' and scroll down to see a list of results.
Alternatively, NVA geosites may be searched for by spatial criteria. On the search form click the map. This will open the map viewer. Zoom in using the magnifier tool then use the polygon tool (indicated by a rectangle) to draw an outline of your area of interest - this need not be a simple rectangle. Double click to close the polygon then click the green tick to return to the NVA and load your polygon as a spatial search term. Click 'Search' and scroll down to see a list of results.
When search results are returned you can use the blue 'Details' buttons to explore several levels of site attributes.
From the search results some standardised reports can be generated by checking either 'Comprehensive' or 'Assessment' and then clicking 'Request Reports'.
Limitations - Important Note
The Tasmanian Geoconservation Database is still being developed and refined - persons using it need to consider whether the data is adequate for their purposes. The following limitations should be noted:
The database lists sites of known significance but is not based on a comprehensive State-wide inventory of geoconservation values.
The absence of identified values at a particular location may reflect gaps in the database, and should not be taken as conclusive evidence that geoconservation values are not present. In this situation, an appropriate site-based assessment may be required.
Listings are biased in favour of sites referred to in scientific publications or identified through a limited number of geoconservation assessments.
Sites on public land are better represented than sites on private land.
Soil sites are particularly poorly represented.
The TGD may be expanded in future to include sites identified through systematic theme-based inventories focussing, for example, on stages in earth history or types of geomorphic processes. This will provide a more comprehensive basis for addressing the TGD criteria concerning 'representative examplars' (i.e. sites that illustrate the natural range or diversity of types within a class of feature).
Highly sensitive sites are not included in published versions of the database.
The mapping precision and level of documentation for geoconservation sites is variable.
The boundaries of some larger sites have been determined using air photos or other desktop methods and require verification in some cases. Other sites have been accurately mapped in the field using a GPS or other reliable method.
The database contains only a brief description of some sites, particularly for older listings. Recently listed sites are generally better documented.
Site listings are occasionally revised and sites may be added after the annual meeting of the Reference Group.
History
In 1979 the Geological Society of Australia published a report Geological Monuments of Tasmania - a descriptive list of fifty or so geological features and landforms. This was a precursor of more detailed inventories by the Parks and Wildlife Service and the (then) Forestry Commission from the 1990s onwards. These and other sources were compiled as a single digital dataset as part of National Estate component of the 1997 Commonwealth-Tasmania Regional Forest Agreement.
Tasmanian Geoconservation Database Reference Group
In 1999, the Department commenced active management of the geoconservation database. An expert panel, the Tasmanian Geoconservation Database Reference Group, was convened to assess site nominations and amendments. This panel brings together expertise in different aspects of the earth sciences. The current members include scientists from the University of Tasmania, industry and government departments and its current Terms of Reference can be found below.
The TGD was published on the LIST in 2006 and on the Natural Values Atlas in 2011. New sites may be updated annually (
see Listing Process).
Examples of Geoconservation Sites
Pedder River Estuary
Pedder River Estuary - Movement of sand along a beach by waves, also known as longshore drift, has combined with river processes to push the mouth of the Pedder River nearly 3 km south along Kenneth Bay.
copyright: R. Eberhard
Pachydermal weathering in sandstone
Pachydermal weathering - Some sedimentary rock types weather to an elephant skin pattern. This particular site is referred to in a scientific paper that describes rocks on Mars, where similar features have been reported.
copyright: Nathan Duhig
Karstic River capture at Vanishing Falls
Karstic river capture at Vanishing Falls - The Salisbury River cascades off the dolerite carapace of Precipitous Bluff to disappear underground into a limestone karst system.
copyright: R. Eberhard
Gardiner Point Precambrian ripples
Gardiner Point Precambrian ripples - Wave ripples preserved for more than half a billion years crop out adjacent to modern ripples now forming in sand at the mouth of the Arthur River.
copyright: R Eberhard
Du Cane Range glaciated terrain
Du Cane Range - Glacial ice eroded parts of the central plateau dolerite sheet into deep, steep-sided valleys separated by narrow aretes. We see a lot of dolerite here in Tasmania but this rock type is uncommon elsewhere in the world.
copyright: G. Dixon
Blanket bog peat soil
Blanket bog peat soil - Organic-rich soils are characteristic of blanket bogs, which only develop under certain climatic conditions and are globally rare. In Tasmania they are associated with extensive buttongrass moorlands.
Pedra Branca phosphatic flowstone
Pedra Branca phosphatic flowstone - Guano from nesting seabirds interacting with rock weathering processes has produced a suite of rare mineral coatings at remote Pedra Branca rock.
copyright: M. Pemberton
Interview River transgressive sand sheets
Interview River transgressive sand sheets - Mobile sands advance inland in response to relentless onshore winds on Tasmania's west coast. These examples are mostly free of imported marram grass widely used last century to stabilise dunes in many parts of Tasmania.
copyright: R. Eberhard
Maria Island fossil beds
Maria Island fossil beds- Floating ice contributed rounded glacial dropstones that pepper this incredibly rich fossil site, which is considered to be internationally significant.
copyright: R. Eberhard
Birchs Inlet terraces
Birchs Inlet terraces - Deep gravel beds near Macquarie Harbour have been tectonically uplifted and incised by streams to create a dramatic flight of terraces. Rivers in this area have distinct meandering forms.
copyright: I. Houshold
See Also: