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|Global Geochemical Baselines Working Group|
The Working Group on Global Geochemical Baselines, operating under the auspices of both the International Union of Geological Sciences (IUGS) and the International Association of Geochemistry (IAGC), has the long-term goal of establishing a global geochemical database to document the concentration and distribution of chemical elements in the Earth’s near-surface environment. The database and accompanying element distribution maps represent a geochemical baseline against which future human-induced or natural changes to the chemistry of the land surface may be recognized and measured.
There is worldwide concern about the potentially damaging effects of chemicals in the environment on the health of humans, animals, agriculture, and ecosystems. Economic and population growth exacerbate such problems as land degradation and pollution from uncontrolled urbanization, industrialization, and intensive agricultural practices. These and other problems are having an impact on the geochemistry of the Earth’s surface and the sustainability of its life-support systems from the local to the global scale.
Defining and understanding the current abundance and spatial distribution of chemicals in different environmental compartments (e.g. soils, sediments, surface and ground water) are essential first steps in being able to recognize and quantify natural or human-induced changes in the future. Dr. Mary Lou Zoback, former President of the Geological Society of America, stated the issue eloquently:
“Documenting and understanding natural variability is a vexing topic in almost every environmental problem: How do we recognize and understand changes in natural systems if we don’t understand the range of baseline levels?” (Zoback, 2001).
Systematic geochemical mapping is the best method available to provide this information about the natural variability of the geochemical background. Geochemical maps have traditionally been valuable in addressing a wide range of environmental problems at the local to national scale, as well as for identifying potential mineral resources. Several decades of geochemical mapping by national geological surveys and related organizations throughout the world have resulted in a wealth of valuable information. However, many of these data sets cannot readily be applied to broader regional or global studies because there was no standardization of the sampling and analytical protocols used. It was this issue that led to the establishment of the predecessor of the current Working Group.
The Working Group traces its origins to 1988 as Project 259, International Geochemical Mapping, of the International Geological Correlation Program (IGCP), now known as the International Geoscience Program. IGCP is a cooperative enterprise of the United Nations Educational, Scientific and Cultural Organization (UNESCO) and IUGS. It was also during this phase, in 1990, that IAGC began its support of the project. IGCP 259 ran until 1992 under the leadership of Dr. Arthur G. Darnley of the Geological Survey of Canada. The project’s final report, A global geochemical database for environmental and resource management, was published by the Earth Sciences Division of UNESCO with financial support from IUGS, IAGC, Association of Exploration Geochemists (now Association of Applied Geochemists), International Atomic Energy Agency, and the Royal Society. The report provided a comprehensive review of methods of regional- and national-scale geochemical mapping. It also detailed the requirements necessary for establishing a global geochemical database through multi-media, low-density sampling on the basis of the Global Reference Network (GRN).
From 1993 to 1997, the project continued under IGCP as Project 360, Global Geochemical Baselines, again under the leadership of Arthur Darnley. The design of the GRN was finalized and sampling sites were selected in a statistically random manner. Standardized methods for geochemical sampling, sample preparation, chemical analysis, and data management to be used in conducting the global-scale geochemical survey, agreed upon by representatives of more than 100 countries, were also prepared during this phase of the project.
Following completion of the two IGCP projects, IUGS, in collaboration with IAGC, established the current Working Group on Global Geochemical Baselines in 1997. It was also at this time that Arthur Darnley transferred leadership of the group to Prof. Jane Plant (British Geological Survey, now at Imperial College) and Dr. David B. Smith (U.S. Geological Survey), who were co-leaders until 2008. At that time, Prof. Plant stepped down and Dr. Xueqiu Wang of the Institute of Geophysical and Geochemical Exploration in Langfang, China became the new co-leader.
The current Working Group’s main objective is to encourage and facilitate the population of the GRN worldwide through application of the sampling, sample preparation, analytical, and data management protocols established in the earlier phases of the project. In order to accomplish this objective, the current activities of the Working Group include:
David B. Smith