Clay minerals in Arctic Ocean surface sediments

This dataset includes clay mineral data from 1672 surface sediment stations used to produce the four distribution maps shown in Figure 5-4 of Stein (2008). Clay minerals are determined by XRD technique using the clay fraction separated by Atterberg method. From the clay fraction, texturally oriented specimens are produced and then analyzed by means of an X-Ray diffraction system. In general, the measurements are performed on untreated and glycolated samples, both from 2 to 40° 2θ with a step size of 0.02° 2θ/s. An additional slow scan is performed between 28 and 30.5° 2θwith a step size of 0.005° 2θ/s. The following peaks are used to identify clay minerals: 17 Å for smectite, 10 Å and 5 Å for illite, and 7 Å for kaolinite plus chlorite. To differentiate kaolinite and chlorite, the intensity ratios of the 3.58 Å-kaolinite peak and the 3.54 Å-chlorite peak, identified by slow scan, can be used. Relative clay-mineral contents are calculated by using empirical factors after Biscaye (1965) and assuming that the four determined clay minerals represent 100% of the clay minerals. Maps have been compiled using the Ocean Data View software (Schlitzer, 2001) and data from Naidu and Mowatt (1983), Darby et al. (1989), Berner (1991), Stein et al. (1994, 2004), Nürnberg et al. (1995), Kalinko et al. (1996), Levitan et al. (1996), Wahsner et al. (1996, 1999), Rossak et al. (1999), Viscosi et al. (2003), and Saukel (2006; data later published in Saukel et al., 2010).