Offshore sediment samples of coastal compartments of western Victoria, Australia
Description
This dataset is composed of 138 surficial sediment samples collected within six coastal compartments of western Victoria, Australia. Unconsolidated substrate areas of the shoreface and inner continental shelf were targeted. 15 samples were collected in the compartment of Discovery Bay (DB), 17 in Portland (PL), 27 in Port Fairy (PF), 31 in Port Campbell (PC), 37 in Great Ocean Road (GR) and 11 in Torquay (TQ), between October 2018 and November 2020. Most samples were collected with a Shipek grab (n = 118) and only 20 samples (PF01-PF20) were collected with a Van Veen. The shallowest samples (PF11 and PF11) were retrieved from 4 m depth whereas the deepest sample (PC01) was collected from depths of 55 m. Grain size and loss on ignition (carbonate and organic matter) analyses were conducted in the laboratory following salt extraction and oven dry at 60 ºC. Approximately 200 g of sample was dry sieved down to 0 phi at half phi intervals to determine size fractions. Size of material finer than 0 phi was obtained by laser scanning using a Beckman Coulter laser diffraction particle size analyser. Grain size statistics have been calculated using Folk and Ward (1957) formulae. Individual sample results were obtained by running the grain size distribution and statistic software GRADISTAT (Blott and Pye, 2001). Approximately 4 g of sediment per sample were used for determining carbonate and organic matter content via loss on ignition (Dean, 1974; Heiri et al., 2001). For that, crushed samples were placed in ceramic crucibles and exposed for 1 h at 105 ºC, 2 h at 550 ºC and 2 h at 950 ºC in a muffle furnace.
Files
Steps to reproduce
Following analysis, tabulated results extracted from GRADISTAT were appended to sample location. The available shapefile (Offshore_Sediment_Samples_WesternVictoria) contains several fields. Sample name in shapefile is represented by the field "Sample". Sample name convention such as "DB01" corresponds to sample 01 collected within the Discovery Bay (DB) compartment. "POINT_X" and "POINT _Y" correspond to the coordinate location of individual samples. "OM" and "CaCO3" correspond to percentages of Organic Matter and CaCO3 in sample respectively. "SAMPLETYPE", "TEXTUGROUP" and "SED_NAME" describe the sample type, texture group and sediment name, respectively, as extracted from GRADISTAT. Mean grain size, Sorting, Skewness and Kurtosis are represented by the "MEAN_", "SORT_", "SKEW_" and "KURT_" fields respectively. These are followed by "M", as in "MEAN_M", for units in metric system; "Phi" for the traditional logarithmic scale unit; and "Desc" for description of each parameter. D10, D50 and D90 are also included as individual fields, both in metric and Phi units. Gravel, Sand and Mud fraction percentages in each sample have their designated columns too. Shapefile can be open using any GIS software of program language.