Bulk chemistry of Saharan shergottite Dar al Gani 476

We report on major and trace element analyses obtained by, respectively, inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrornetry (ICP-MS) of three different aliquots of the new Saharan shergottite Dar al Gani (DaG) 476. The new analyses are in excellent agreement with previous data (Zipfel et al., 2000). Ba, Sr and U abundances, together with the presence of carbonate, suggest that the sample has been significantly weathered. Three rare earth element (REE) patterns (normalized to CI) determined on three different aliquots of the sample all show similar shapes. The heavy REEs are flat with a slight depletion at the heavy end and a strong depletion from Dy to Pr. All of the patterns display an upturn to La which we interpret as being caused by the introduction of a terrestrial component. Taking the terrestrial contamination into account, this study demonstrates that DaG 476 is one of the most depleted of the shergottites, and, just like Queen Alexandra Range (QUE) 94201 (Dreibus et al., 1996), displays very low Zr/Hf ratios. It appears that the Zr/Hf ratios of shergottites are not uniform, and have been significantly fractionated by martian mantle processes.