Brief description
Wistari Reef is a lagoonal platform reef, situated on the Tropic of Capricorn, within the Capricorn and Bunker region of the southern Great Barrier Reef. Nine surface samples were taken from the lagoon area and analysed to determine the grainsize and the sorting coefficient (expressed as the standard deviation of grainsize) within each sample. The results exhibited much variation in grainsize and sorting. A slightly better trend is revealed if the 'lagoon' physiographic zone is sub-divided into 'deep-lagoon' samples (e.g. S16) and 'patch-reef dominated' samples (e.g. S11). The sediments of the 'deep-lagoon' are typically poorly sorted medium to fine sands, with little contribution from in situ patch reef growth. The 'patch-reef dominated' sediment is a poorly sorted medium sand, and contains a high proportion of coarser grains which are derived from patch reefs within the lagoon.Lineage
Statement: Surface samples were collected on reef walks or on boat transects across Wistari Reef. Deeper samples were obtained by diving. Samples were collected using a hand-held scoop and 600ml plastic bottles. Sediment samples were sieved in order to determine modal particle diameters, and sorting data. Samples were first dry sieved. Sieves of sizes -1.0phi to 2.5phi were stacked and installed on a sieving shaker. Samples were weighed out to approximately 250g, and each sample was sieved for 15 mins to ensure correct separation of size fractions. Each fraction was then removed from the sieve and weighed. The size fractions 2.5phi, 3.0phi, 3.5phi and 4.0phi were pre-weighed, and wet sieved separately using a low pressure water hose, through smaller micropalaeontological sieves. Sediment textures are expressed in terms of mean grainsize, and sorting coefficient, represented by standard deviation.
Statement: Scanned histograms are used to highlight the percentage of sediments within each grainsize bracket. The exact percentage figures are not available. Much variation in grainsize and sorting was seen within the sediments. It may be better to sub-divide the samples into those that were collected from the 'Deep-Lagoon', and those that were collected from the 'Patch Reef Dominated' areas.
Parameters: Sample, latitude (d,m,s), longitude (d,m,s), grainsize brackets (phi), percentage of sediments in grainsize brackets (%).
Notes
CreditFunded by The Australian Research Council (ARC)
Credit
The Australian National University (ANU)
The Australian National University (ANU)
Purpose
To provide an overview of the sedimentary zones of Wistari Reef. Conducted as part of a broader study looking at Holocene production and accumulation of sediments on Wistari Reef.
To provide an overview of the sedimentary zones of Wistari Reef. Conducted as part of a broader study looking at Holocene production and accumulation of sediments on Wistari Reef.
Issued: 04 06 2007
Data time period: 1998 to 1998
text: westlimit=151.5; southlimit=-23.5; eastlimit=152; northlimit=-23
text: uplimit=5; downlimit=2
Subjects
COASTAL PROCESSES |
Coral Reefs |
EARTH SCIENCE |
OCEANS |
Oceans | Marine Sediments | Sediment Grain Size |
environment |
grainsize_size_category |
latitude |
longitude |
User Contributed Tags
Login to tag this record with meaningful keywords to make it easier to discover
Other Information
(ANU_Ryan_Lag_2_data.JPG)
global : aa28d650-0d75-11dc-b244-00188b4c0af8
Identifiers
- global : 8d79f1f0-125d-11dc-a108-00188b4c0af8
