The ANCA directory contains two scanned images, geology.tif and veg.tif. The geology map contains the following information: Base map compiled from topographic base sheets prepared by Australian Aerial Mapping Pty. Ltd. and supplied by The British Phosphate Commissioners. Geology and compilation by J. Barrie 1965-66 Drawn by J. Kopros Bureau of Mineral Resources, Geology and Geophysics CHRISTMAS ISLAND SURVEY 1965-66. To accompany Record 1967/37. The vegetation map contains the following message: Vegetation map - Accompanies Mitchells 1985 Report. ONLY COPY!! See File 80/13 for Report. It is based on J Barries geology map.

Laser DEM Grids consists of 27 digital elevation model grids. The Arcview grid files were constructed from the Airborne Laser Scanning shapefiles. The Laser DEM grid tiles cover the eastern portion of the Christmas Island. Each grid contains the height in metres of the ground surface with a value every one metre on the ground.

Product no longer exists, please refer to GeoCat #30413 for the data

This dataset contains polygons that bound parts of Irvine Hill forest. The polygons were constructed by drawing lines that join points which were pegged out as being boundaries of the Irvine Hill area. The main points were supplied by Whelans. The line joins and polygon making process was done by Geoscience Australia. The shapefile containing the data is: forestedge_irvineh.shp. Details of the fields can be seen below: Field Type Width Decimal---------------------------------------------------Shape FIELD_SHAPEPOLY 8 0Area FIELD_DECIMAL 12 3Perimeter FIELD_DECIMAL 12 3Plot3pef2_ FIELD_DECIMAL 11 0Plot3pef2_ FIELD_DECIMAL 11 0Entity FIELD_CHAR 14 0Layer FIELD_CHAR 32 0Elevation FIELD_DECIMAL 18 5Thickness FIELD_DECIMAL 18 5Color FIELD_DECIMAL 11 0Pointnumbe FIELD_DECIMAL 11 0Pointheigh FIELD_DECIMAL 18 5Pointcode FIELD_CHAR 8 0Sourcethm FIELD_CHAR 16 0Hectares FIELD_DECIMAL 16 3

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

A useful spin off of the soft photogrammetry is the opportunity to get one metre contours over the disturbed areas of the Island. For the north-east area of the Island 2km X 2km DEM contour tiles have been trialed in the CIGIS. Most are at a contour interval of 5 metres but tiles 2269 and 2469 have been done at a one metre contour interval. The DEM contours are surface contours. They pick up the reflective surface beneath the aircraft. The reflective surface may be the ground or it may be a dense vegetation canopy or rooftops etc. Further one metre contour coverage can be prepared on a cost recovered basis.

This is a national seamless data product aimed at regional or national applications. TOPO 2.5M 1998 contains a small scale vector representation of the topographic mapping features of Australia. The data include the following themes: Hydrography - drainage networks including rivers, lakes and offshore features; and Infrastructure - roads, railways, localities and built-up areas. Data was primarily sourced from Geoscience Australia`s GEODATA TOPO-250K data set however all features were revised in 1998. Free online and CD-ROM (fee applies).

Lord Howe Island is a small, mid-ocean volcanic and carbonate island in the southwestern Pacific Ocean. Skeletal carbonate eolianite and beach calcarenite on the island are divisible into two formations based on lithostratigraphy. The Searles Point Formation comprises eolianite units bounded by clay-rich paleosols. Pore-filling sparite and microsparite are the dominant cements in these eolianite units, and recrystallised grains are common. Outcrops exhibit karst features such as dolines, caves and subaerially exposed relict speleothems. The Neds Beach Formation overlies the Searles Point Formation and consists of dune and beach units bounded by weakly developed fossil soil horizons. These younger deposits are characterised by grain-contact and meniscus cements, with patchy pore-filling micrite and mirosparite. The calcarenite comprises several disparate successions that contain a record of up to 7 discrete phases of deposition. A chronology is constructed based on U/Th ages of speleothems and corals, TL ages of dune and paleosols, AMS 14C and amino acid racemization (AAR) dating of land snails and AAR whole-rock dating of eolianite. These data indicate dune units and paleosols of the Searles Point Formation were emplaced during oxygen isotope stage (OIS) 7 and earlier in the Middle Pleistocene. Beach units of the Neds Beach Formation were deposited during OIS 5e while dune units were deposited during two major phases, the first coeval with or shortly after the beach units, the second later during OIS 5 (e.g. OIS 5a) when the older dune and beach units were buried. Large-scale exposures and morphostratigraphical features indicate much of the carbonate was emplaced as transverse and climbing dunes, with the sediment source located seaward of and several metres below the present shoreline. The lateral extent and thickness of the eolianite deposits contrast markedly with the relatively small modern dunes.

Amino acid racemization (AAR) dating of the eolianite on Lord Howe Island is used to correlate several disparate successions and provides a geochronological framework that ranges from Holocene to Middle Pleistocene time. The reliability of the AAR data is assessed by analysing multiple samples from individual lithostratigraphic units, checking the stratigraphic order of the D/L ratios and the consistency of the relative extents of racemization for a suite of seven amino acids. Three aminozones are defined on the basis of the extent of racemization of amino acids in land snails (Placostylus bivaricosus) and 'whole-rock' eolianite samples. Aminozone A includes Placostylus from modern soil horizons (e.g. mean D/L-leucine ratio of 0.03±0.01) and whole-rock samples from unconsolidated lagoonal and beach deposits (0.10±0.01-0.07±0.03). Aminozone B includes Placostylus (0.45±0.03) and whole-rock samples from beach (0.48±0.01) and dune (0.45±0.02-0.30±0.02) units of the Neds Beach Formation, deposited during OIS 5. The oldest, Aminozone C, comprises Placostylus recovered from paleosols (0.76±0.02) and whole-rock eolianite samples (0.62±0.00) from the Searles Point Formation, which indicate the formation was likely deposited over several Oxygen Isotope Stages (OIS), during and prior to OIS 7. These data support independent lithostratigraphic interpretations and are in broad agreement with U/Th ages of speleothems from the Searles Point Formation and corals from the Neds Beach Formation, and with several TL ages of dune units in both formations. The AAR data reveal that eolianite deposition extends over a significantly longer time interval than previously appreciated and indicate that the deposition of the large dune units is linked to periods of relatively high sea level.