Page 6 - Geochemical Anomaly and Mineral Prospectivity Mapping in GIS

VII

PREFACE

Twenty-five years ago, when the second volume of the Handbook of Exploration
Geochemistry was published (Howarth, 1983), computers were just becoming useful
tools in the analysis of mineral exploration data sets but mapping of geochemical
anomalies and prospective areas still usually involved overlaying transparent
geochemical map(s) and a geological map on a light table. The late 1980s through the
1990s saw rapid and far-reaching developments in quantitative techniques for mapping
geochemical anomalies and mineral prospectivity due to the substantial improvements in
the efficiency and availability of computer hardware and software (Agterberg, 1989)
including geographic information system (GIS) technology (Burrough, 1987; Bonham-
Carter and Agterberg, 1990; Maguire et al., 1991). Two textbooks and several papers
published in exploration-related literature have explained and documented various GIS-
aided and/or GIS-based methods for analysis of multiple geoscience spatial data sets in
order to derive and synthesise pieces of geo-information that are pertinent to the
decision-making process at every scale of target generation in mineral exploration. In
“Geographic Information Systems for Geoscientists: Modelling with GIS”, Bonham-
Carter (1994) introduced ideas and methods of spatial analysis and modeling in GIS,
especially those that are useful for characterising spatial associations between a set of
geo-objects of interest (e.g., deposit-type locations) and individual sets of (indicative)
spatial features (e.g., geochemical anomalies) in order to develop predictive models of
the former set. In “Information Synthesis for Mineral Exploration”, Pan and Harris
(2000) introduced various methods for optimal assimilation of specific pieces of geo-
information extracted from various spatial data sets in order to derive optimised geo-
information for decision-making in mineral exploration. Nowadays, mapping of
geochemical anomalies and/or prospective areas involves stacking digital geochemical
and geological maps on top of each other on an electronic light table (i.e., in a GIS).
The objective of this book is to document, survey and demonstrate various GIS-aided
and/or GIS-based techniques for mapping of geochemical anomalies and prospective
areas during the target generation phase of mineral exploration. This volume consists of
three parts, all centred on the theme predictive modeling or mapping and built upon
particular notions and/or methods presented in the aforementioned textbooks and in
various papers in exploration-related literature. Built upon the natural link between
mapping of exploration targets and GIS, the chapters in Part I review and couple the
concepts of (1) mapping geochemical anomalies and mineral prospectivity and (2)
spatial data models, management and operations in a GIS. Built upon the remarks of
Reimann (2005, pp. 369) that “Although GIS techniques appear to have simplified
geochemical mapping tremendously, most systems do not allow for fast and correct class