Sediment Data for Carnarvon Shelf  

Authors / CoAuthors

Abstract

Geoscience Australia carried out a marine survey on Carnarvon shelf (WA) in 2008 (SOL4769) to map seabed bathymetry and characterise benthic environments through co-located sampling of surface sediments and infauna, observation of benthic habitats using underwater towed video and stills photography, and measurement of ocean tides and wave-generated currents. Data and samples were acquired using the Australian Institute of Marine Science (AIMS) Research Vessel Solander. Bathymetric mapping, sampling and video transects were completed in three survey areas that extended seaward from Ningaloo Reef to the shelf edge, including: Mandu Creek (80 sq km); Point Cloates (281 sq km), and; Gnaraloo (321 sq km). Additional bathymetric mapping (but no sampling or video) was completed between Mandu creek and Point Cloates, covering 277 sq km and north of Mandu Creek, covering 79 sq km. Two oceanographic moorings were deployed in the Point Cloates survey area. The survey also mapped and sampled an area to the northeast of the Muiron Islands covering 52 sq km. Seabed sediment samples were collected by a Smith McIntyre grab at a total of 275 locations, divided between Mandu Creek (n=81), Point Cloates (n=92), Gnaraloo (n=92) and Muiron Islands (n=10). The full sample set represents 102 sampling stations at which two sediment grabs were collected in close proximity. The exception to this was at Mandu Creek where three grabs were collected at 19 stations and at Gnaraloo where single grabs were taken at three stations. At Muiron Islands, single grabs were collected at five stations and two grabs at three stations (see Brooke et al. 2009).

Product Type

dataset

eCat Id

72039

Contact for the resource

Keywords

• Marine DataBathymetry Grid

( Theme )

• abiotic surrogates

( Theme )

• sedimentology

( Theme )

• marine

( Theme )

• CERF

• AU-WA

Australian and New Zealand Standard Research Classification (ANZSRC)

• Marine Geoscience

• Published_External

Publication Date

2011-01-01T00:00:00

Creation Date

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Australian Government Security ClassificationSystem    

Classification - unclassified

Legal Constraints

Creative Commons Attribution 4.0 International Licence    

Access - license

Use - license

Status

Purpose

Maintenance Information

asNeeded

Topic Category

geoscientificInformation

Series Information

Lineage

Sediment grabs typically recovered about 0.1 cubic metres of undisturbed sediment, from which a 250 - 500 g sub-sample was taken to a depth of ~5 cm. Sub-samples were described from visual inspection, noting grain size, sorting, composition and Munsell colour then stored in plastic bags and refrigerated. In the laboratory, samples were used for grain size analysis and measurement of carbonate content on separate splits. Grain size measurement was undertaken by wet sieving to determine mud (less than 63 microns), sand (63-2000 microns) and gravel (greater than2000 microns) fractions as percentage of dry weight. A separate sub-sample (~1g) was used for laser diffraction measurement of the mud and sand fractions using a Malvern Mastersizer 2000, with results expressed as percentage of the total particle volume based on an average of three measurements on each sample. Summary statistics include arithmetic mean, standard deviation, skewness and kurtosis. Carbonate content was measured on the bulk fraction, sand fraction and mud fraction by acid digestion and measurement of resultant pressure, following Muller and Gastner (1979). The carbonate content of the gravel fraction was determined by visual assessment. Sediment data for the Carnarvon Shelf are a first generation product derived from the physical samples. No transformation of the data has been undertaken.

Parent Information

Extents

[-23.89, -21.56, 113.21, 114.37]

Reference System

Spatial Resolution

Service Information

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Source Information

CERF Marine Biodiversity Hub