Hydrocarbon Lithogeochemistry

Zinc Concentrations Map

Propyne Concentrations

Hydrocarbon Gas and Lithogeochemistry Database: a European Union funded research programme by Mercury Hydrocarbons Limited investigated the possible use of light hydrocarbon gases within rocks and litho-geochemistry in the search for carbonate hosted zinc-lead and other deposits. GSI now has the sole rights for the dissemination of the results of this extensive data set for the Irish part of the research programme. The data set is available in both tabular and digital formats.

There are 2,500 samples (1 per 9km²) from throughout the Irish Midlands covering areas known to be mineralized (Navan, Tynagh, Silvermines, Galmoy, Lisheen and others) and those not. The samples were analysed for:

Light hydrocarbon gases Methane, Ethane, Ethene, Propane,
Propene, Propyne, Methanol, Isobutane,
N-butane Acetaldehyde, and C5+ gases.
Major elements Ca and Mg.
Minor elements Cu, Pb, Zn, Mn, Fe and As.
Other parameters Insoluble Residue and Total Organic
Carbon (TOC)

The rationale for carrying out the non-hydrocarbon analyses was as follows:

Ca and Mg Limestone purity
Insoluble residue Limestone purity
Mg Dolomitization
Total Organic Carbon Relationship between residual organic
matter and the content of individual
hydrocarbon gases
Cu, Pb and Zn Irish carbonate ore elements
Mn, Fe and As Suggested a pathfinders for Irish carbonate-hosted base metal mineralization

From the study it was suggested that propyne was the only hydrocarbon that "defined" the main carbonate-hosted zinc-lead deposits (Navan, Tynagh, Silvermines, Galmoy and Lisheen). The study also highlighted important regional differences in the data set as follows:

Northern part of the study area Elevated TOC, methane, propyne, Cu, Mn, and Fe.
Southern part of the study area Elevated methane, propyne, Zn, Fe and Mg.

For further details please contact Gerry Stanley. Tel: 01-6782863 Fax:01-6782589