The Geology And Water Chemistry Of The Hellisheidi, Sw-Iceland Carbon Storage Site

10. Helgi A. Alfredsson, Eric H. Oelkers, Björn S. Hardarsson, Hjalti Franzson, Einar Gunnlaugsson, Sigurdur R. Gislason
2012 Zenodo  
The subsurface rocks at the Hellisheidi carbon injection site are primarily olivine tholeiite basalts consisting of lava flows and hyaloclastite formations. The hyaloclastites are low permeability glassy rocks formed under ice and melt water during glaciations that serve as the cap rock at the injection site; the boundaries between hyaloclastites and lava flows and those between individual lava flows boundaries are preferential fluid flow pathways. Some alteration is observed in the
more » ... in the hyaloclastite cap rock situated at 100–300 m depth consisting primarily of smectite, calcite, Ca-rich zeolites, and poorly crystalline iron-hydroxides. Alteration increases with depth. These alteration phases lower the porosity and permeability of these rocks. Carbon dioxide injection will be targeted at a lava flow sequence at 400–800 m depth with the main aquifer located at 530 m depth. Loss on ignition suggests that over 80% of the primary rocks in the target zone are currently unaltered. The target zone rocks are rich in the divalent cations capable of forming carbonates; on average 6 moles of divalent cations are present per 1 kg of rock.
doi:10.5281/zenodo.12858 fatcat:5mhkx7p6crbctows5j7pnpqv3i