A Biogeochemical study of Pandanus candelabrum in Liberia: A potential geobotanical indicator for kimberlite pipes in tropical terranes

Abstract

Pandanus is recently recognized as a new geobotanical indicator for kimberlite diatremes in Liberia. The plant also grows in non-kimberlite terranes making it critical to determine the differences, similarities or contrasts between the chemical nutrient uptake of elements into the tissues (roots, fronds, bark and trunk) of the plant from substrates of fertile kimberlite and those of non-economic regional country rock.A random sampling survey was adopted in which 20 soils and 59 Pandanus tissues of roots, fronds trunks, and bark were collected over a kimberlite pipe in NW Liberia. In addition, 9 soils and 27 Pandanus samples covering the equivalent botanical tissues, except for trunk, were obtained over three granodiorite gneiss, non-kimberlite locations. A total of 5,865 analyses for major and trace elements including REE were obtained by Inductively Coupled Plasma Mass Spectrometry on Pandanus candelabrum and their soil hosts.Major Mg and trace elements of Co, Cr, Ni, Ba, Cs, Nb, Rb, Sr, Zr and REEs are enriched in the kimberlitic eluvium compared to soils from granodiorite gneisses. Diagnostic Cr, Ni, Ba, Rb, Sr, Zr and REE in Pandanus tissues on the kimberlite pipe have distinctive concentrations making the plant a new biogeochemical tool in the exploration for kimberlites in tropical cratonic terranes.