GENERAL CONCEPTS OF GEOCHEMICAL MAPPING AT GLOBAL, REGIONAL, AND LOCAL SCALES FOR MINERAL EXPLORATION AND ENVIRONMENTAL PURPOSES

  • Alecos Demetriades IUGS Commission on Global Geochemical Baselines
  • David B Smith IUGS Commission on Global Geochemical Baselines http://orcid.org/0000-0001-8396-9105
  • Xueqiu Wang UNESCO International Centre on Global-scale Geochemistry

Abstract

Planning an effective geochemical sampling campaign to meet survey objectives should be based on a phased or stepwise use of applied geochemical methods, starting from a desktop study that collects and evaluates all available data and information. This is followed by a field investigation, which should begin with an orientation survey, where a variety of sampling media, sample preparation methods, and analytical protocols are tested with the objective of finding the most cost-effective methodology to be applied in the succeeding steps of the follow-up and detailed investigations. Sampling is the most important part in any geochemical survey for mineral exploration or environmental purposes. Apart from sampling, another significant part of a survey is sample preparation. Mistakes in sampling and sample preparation are difficult to trace and affect the final results and success of a survey. Hence, these are the two parts of a geochemical survey that should be performed with the utmost care. Sampling procedures for stream sediment, overbank or floodplain sediment, stream water, ground water, rock, and residual soil are described, as well as sampling in the laboratory. The importance of randomisation of samples and implementation of strict quality control procedures are also discussed. Finally, it is emphasised that the success of any geochemical survey, including global geochemical baseline mapping, depends on the training of the applied geochemist.

Author Biographies

Alecos Demetriades, IUGS Commission on Global Geochemical Baselines
Treasurer and Chairperson of Sampling Committee, IUGS Commission on Global Geochemical Baselines
David B Smith, IUGS Commission on Global Geochemical Baselines

Co-Leader of the IUGS Commission on Global Geochemical Baselines

Xueqiu Wang, UNESCO International Centre on Global-scale Geochemistry

Executive Director

Published
22-12-2018