Geochemistry-dataset-Ironstones

Table 2 consists of chemical composition analyses of ironstone rock samples. Major elements (Ca, Fe, Mg, Mn, P, Si, and Ti) were determined using a borate fused disc and X-ray Fluorescence (XRF); Loss on Ignition was determined at 1000°C; Ag, Al, As, Ba, Be, Bi, Cd, Ce, Cr, Cu, Hf, K, Li, Mo, Na, Ni, Pb, S, Sb, Sc, Sr, V, and Zn were determined by multi-acid digestion and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS); Co, Cs, Dy, Er, Eu, Ho, La, Lu, Nb, Nd, Pr, Rb, Sm, Tb, Th, Tm, U, Y, Yb, and Zr were determined using a Lithium metaborate fused disc and ICP-MS; Cl and F were determined by Ion Specific Probe; H₂O^- was determined by gravimetry and H₂O⁺ by Penfield-infrared method. Precision was better than 20% for all elements except K (40%) and Ag (57%). Accuracy was better than 20% for all compounds excepting H₂O⁺ (26%) and P (28%) and was not determined for H₂O^-, Co, Cs, Nb, Rb, and Zr because no certified values were available.Table 3 consists of U-Th/He analysis of ironstone grains performed at Caltech using the methods described by Monteiro et al. (2014).<br>