Surficial Sediments 
of the Australian Seabed
auSEABED Coverages
now available

 
 
 
This site catalogs the national scale GIS coverages 
which are available for the Australian region
Click to enlarge
 INTRODUCTION
GRIDDED DATASETS
  •     Data grids
  •     Associated grids

    • POINT DATASETS
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    INTRODUCTION
    A set of digital products has been developed for auSEABED and these may be obtained from The University of Colorado subject to some conditions of use required by the Australian Defence Forces. Email request. They are supplied for purposes of teaching and scientific research, but specialized datasets for other uses may also be ordered, for instance of special areas with higher resolution.

    GRIDDED DATASETS
    a. Data Grids
    The format is ARCView / Spatial Analyst ASCII grid, with values variously integer or decimal.
    The grid lower left corner cell is centred on 110.05 deg(E), -47.45 deg(S) and there are 400 rows by 475 columns.
    The grid files are too large for EXCEL, but can be opened in ArcView (Spatial Analyst), other GIS, and mathematical applications like MATLAB.
     
    Grainsize Sorting Gravel Sand Mud
    This statistic is a consensus of: Moment Mean <ELSE> Median <ELSE> Inman Graphic Means <ELSE> Folk Graphic Mean; not Modal Grainsize. It refers to all the loose seabed materials, ie not 'rock'. Based on Moment Standard Deviation only. It refers to all the loose seabed materials, ie not 'rock'. Applies to loose materials on the basis of texture not composition. Thus large shells, coral and nodules are included along with pebbles, boulders, etc. Applies to loose materials on the basis of texture not composition.  Used simply to denote materials of texture <63 microns size; does not refer to composition. It refers to all the loose seabed materials, ie not 'rock'.





    Carbonate Rock Exposure Critical Shear Stress Porosity P-Wave velocity
    Includes all loose carbonate sedimentary and skeletal components: calcareous mud, sand, shell, coral and clasts. 'Rock' is accepted in its textural (bigger than -10phi) and geotechnical (hardness) meaning, not compositional. Thus, coral reef platforms and cemented pavements are included. This grid is of maximum observed rock exposure in each cell. Represents the erodability of loose sediments at the seafloor surface. Calculated using empirical relations  from grainsizes, grainshapes, consolidation and shear strengths. Given as log10; high CSS less erodable. Represents the degree oif void space in the surface sediments. Is primarily calculated, based on grainsizes modified by consolidations. (TBA) 
    (The images and grids will be posted progressively through June 2002.)

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    b. Associated grids
    Spatial density Water Depth Slope
    The number of points (/deg) in each 
    0.1 deg grid cell, including only those 
    from actual field sampling operations 
    (not geomorphic classifications like 
    'coral reef flat'). Green areas 
    have satisfactory data coverage.    		 (TBA) (TBA)
    (Images and grids will be posted progressively through June 2002.)

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    POINT DATASETS
    Some attributes that are described with codes or multiple abundance values cannot be rendered as grids.
    They are available from auSEABED as point datasets, with positions corresponding to the centres of the 0.1 degree grid cells (above).
     
    Munsell Colour Seabed Roughness Grain components Facies classifications
    Seabed colour rendered in real colour 
    via Munsell Codes of 
    Hue / Value / Chroma 
    (GSA Rock Color Chart;
    GretagMacmeth corporation)
    See Explanation    		 Observed surface roughness (eg. 
    clasts, ripples, potholes, upstanding 
    hard skeleton benthos), not wide scale 
    features (eg. sandwaves). This theme 
    is under development. 
    See Explanation    		 (TBA) The fuzzy membership (%) of the 
    dominant classification (facies) 
    based on observed grain components 
    (eg. ooliths, manganese nodules, quartz).

    Legend graphic
    Legend graphic
     
    Legend graphic
    (Images will be posted progressively through June 2002.)
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    Date: 11 Oct 2002
    Copyright: INSTAAR, UnivColorado