Geochemistry

What is Geochemistry?

Collecting a water sample as part
of a research project on exploration
geochemistry, northeastern Ontario.
Photo by OGS staff

In order to determine the chemical composition of the landscape, the OGS undertakes sampling programs across the province that target a variety of materials. The samples are analyzed, by a variety of methods, to determine what elements are present and in what abundance. Materials that are frequently sampled for geochemical analysis include:

• Rocks
• Mineral grains
• Lake sediments (mud from the lake bottom)
• Overburden (soils)
• Groundwater and surface water

OGS Role

The activities of the OGS associated with geochemistry are:

• Regional-scale drift, lake sediment and water surveys: surficial geochemistry.
• Sampling of bedrock conducted as part of regional and thematic mapping projects: lithogeochemistry.
• Groundwater sampling across the province: aqueous geochemistry.
• Research on rocks and minerals to address specific questions or issues.

Geoscience Application

Collecting a stream sediment sample to check
for indications of nearby mineralization,
northeastern Ontario. Photo by J.L. Reid

The results of geochemical analysis, either of rock or overburden samples, are frequently used to assist mineral exploration. The abundance of one or more elements may indicate the presence of nearby mineralization and, thus, provide a target area for follow-up exploration.

Geochemistry is also a key tool in assessing the state of the environment. Geochemical analyses can be used as a tool to determine the naturally occurring levels of elements and substances in the ecosystem or to ascertain if any non-naturally occurring substances are present.

The health of humans and animals is affected by the geochemical composition of the land on which they live and the water they consume. By having a knowledge of areas where health threats exist, these can be addressed or mitigated.