Clay mineral composition of gravity core DG12-GC04 obtained on the Drygalski Basin in the Ross Sea

The samples for clay mineral compositions were collected from GC01 and GC04 at 10 or 20 cm intervals. The organic matter was removed using 10% H2O2, and the fine fraction (<63 μm) was separated using a sieve. The fraction under 2 μm was extracted using Stokes' law, smeared on the slide, and air-dried following Stokke and Carson (1973). An air-dried slide was treated with ethylene-glycol for 24 h. X-ray diffraction (XRD) was performed using a Siemens/Brucker D5005 at Gyeongsang National University with Cu-Kα radiation (40 kV, 35mA). The clay mineral composition was identified based on the basal reflections recorded in the XRD patterns, following the methods of Brown and Brindley (1980) and Moore and Reynolds (1989). The four major clay minerals (illite, smectite, chlorite, and kaolinite) were estimated by semi-quantitative calculation using the method of Biscaye (1965). The analytical precision for the clay mineral composition was approximately ±5%.