Determining main carbonate mineralogy, and the primary components of the non carbonate fraction, at two depths in core GC13, collected from the Capricorn Channel.

A gravity core (GC13) was collected from a depth of 1482 mbsl within the Capricorn Channel, southern Great Barrier Reef (GBR). Analysis of other parameters revealed the Last Glacial Maximum (LGM) sitting at a depth of ~90cm into the core. Two samples were collected for X-ray Diffraction (XRD) analysis; from the sediment surface (GC13-0) representing interglacial sediment, while the second sample, from 90cm (GC13-90) represents glacial sediment. XRD analysis of these samples show a slight increase in carbonate percentage during the interglacial compared to the glacial, with increased clay and quartz during the glacial. During the interglacial there are minor amounts of Mg calcite, which suggests that there is little influence from the reef platform on the sediments during the present sea-level, or that the core is presently below the Mg calcite compensation depth.