Rare Earth and High Field-Strength Elements in the Multani Mitti Clay: A Study Using INAA

Abstract

Instrumental neutron activation analysis was used to determine nine rare earth elements (REE), Sc and five high field-strength elements (HFSE) in the Multani Mitti (MM) clay. Chondrite-normalised rare earth element patterns for the MM clay compared with those for the Post-Archaean Australian Shale (PAAS), Upper Continental Crust (UCC) and North American Shale Composite (NASC) showed enrichment of light REEs and depletion of heavy REEs with a slight negative Eu anomaly. The Multani Mitti clay showed close resemblance to PAAS and NASC in its average REE and HFSE contents. Positive correlations between La/Ce, La/Sm, La/Yb, Zr/Hf, Th/U and Th/Ta ratios predict enrichment of LREEs, Zr and Th and depletion of HREEs. A parent source of felsic origin for the MM clay is also endorsed through the high La/Th and low Th/Sc ratios observed. © 2012 The Authors. Geostandards and Geoanalytical Research © 2012 International Association of Geoanalysts.