In South Wales, 25 sites have been sampled for methane in the two main aquifers, the Carboniferous limestone and the Coal Measures sandstones.
The shale unit present in this area is the Marros Group, which consists of siliceous mudstones and local quartz rich sandstones and conglomerates. The maximum height of the top of the Marros is about 400 m above OD at outcrop in the west, but deepens towards the east to reach depths of over 2500 m below OD.
These summary results are from single sampling visits to each site as part of the methane baseline project. The data are summarised for the South Wales region as a whole and also for individual aquifers, where enough data are available.
|Area||Concentration (mg/l)||Number of
No baseline data are available for the Carboniferous limestone or the Coal Measures in this region.
Contact Rachel Bell for further information.