A gravity core (GC09) was collected from a depth of 166m within the Capricorn Channel, southern Great Barrier Reef (GBR). Analysis of other parameters revealed the Last Glacial Maximum (LGM) sitting at a depth of ~60cm's into the core. For this reason two samples were collected for X-ray Diffraction (XRD) analysis, the first at a depth of 5cm (GC09-5) representing interglacial sediment, and the second from a depth of 60cm (GC09-60) representing glacial sediment. Both samples exhibited high Mg calcite and aragonite, compared with calcite, suggesting that the primary carbonate influx to the core is from the surrounding reef platform, rather than pelagic influences. There was also a 10% increase in non carbonate material during the glacial, and this was primarily made up of feldspars and quartz indicating a relative increase in terrestrial sediment during the LGM.