Termite species variations and their importance for termitaria biogeochemistry: towards a robust media approach for mineral exploration

Abstract

Termitaria (termite mounds) are a widespread and abundant component of tropical savannah ecosystems in northern Australia. Despite their abundance very little systematic research has been carried out on the application of termitaria sampling to mineral exploration in this region. Multi-element biogeochemistry of termitaria from species with the most abundant epigeal mounds (Nasutitermes triodiae (N. triodiae), Drepanotermes rubriceps (D. rubriceps) and Amitermes vitiosus (A. vitiosus)) is characterized and compared. Differences in the biogeochemistry of termitaria built by different species are identified in this biogeochemical study of the termitaria at the Titania Au Prospect, situated proximal to a palaeochannel system in a highly prospective area in northern Australia. In particular, elevated levels of Mo and Au in the coarse sand fraction of the D. rubriceps mounds are observed. Mineralization is expressed in the biogeochemical characteristics of termitaria through up to 15 m of transported regolith, particularly in the fine, silty-clay fraction of the mound samples. This is particularly obvious for Au, As, Zn and Ni, which all show relatively high analytical concentrations within material sampled from termitaria of N. triodiae. These findings show that termitaria can successfully delineate buried mineralization, reinforcing the role that soil biota, such as termites, play in forming surface geochemical anomalies above mineralization buried by transported regolith.