Chemical alterations of the Holbrook chondrite resulting from terrestrial weathering

Major, minor and trace element analysis as well as noble gas measurements were performed on three Holbrook chondrite samples collected fresh in 1912, in 1931, and in 1968. Decreases in metallic iron and MgO and an increase in total iron were detected. Elemental concentrations of Ti, Ca, Al, P, Mn, Ni, and Cr did not change significantly during weathering. While sodium might have been lost, and K slightly enriched, the trace elements C, Rb, and Sr increased at least two-fold during weathering. Gas abundances decreased, and the concentration ratios of noble gas nuclides varied unpredictably.