“…At low temperatures under near surface conditions, the aqueous solution should be dominantly trivalent, except perhaps in alkaline, very strongly reducing pore waters of anoxic marine sediments (Sverjensky, 1984). Therefore, Eu anomalies in fossil biogenic apatite and phosphate concretions have often been associated with strongly reducing environments (e.g., Iliopoulos et al, 2010) regardless if the anomaly is positive (e.g., Kidder et al, 2003;Jiang et al, 2007;Khan et al, 2012;Garnit et al, 2012) or negative (e.g., Kowal-Linka et al, 2014;Fadel et al, 2015).…”