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Geological GHG emission mitigation: a preliminary investigation of crushed basalt as a soil amendment to sequester atmospheric CO2

Geological GHG emission mitigation: a preliminary investigation of crushed basalt as a soil amendment to sequester atmospheric CO2

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​This research has been carried under the Geological Survey Ireland 2017 Short Call. This call provided funding for researchers in academia or industry on the island of Ireland for projects of less than 12 months duration and less than €25,000. 

Please note that the final report has been redacted to remove staff, financial and sensitive information. Some file sizes have been reduced to allow easier uploading/downloading, higher quality files are available on request. Supplemental information is also available on request in most cases. Please contact research[AT]gsi.ie

Disclaimer:  The views expressed in this report are those of the author(s) and not of Geological Survey Ireland or the Department of Climate Action, Communications and Environment.

Lead Applicant: Prof Frank McDermott

Host: University College Dublin

Project Title: Geological GHG Emission Mitigation: A preliminary investigation of crushed basalt as a soil amendment to sequester atmospheric CO2

Project Description: Six plot-scale (16m2) field experiments with adjacent control plots will be established to evaluate the efficacy of crushed basalt as a CO2 sequestering soil amendment for a range of soil types and conditions. The aim is to understand the optimal conditions for accelerated near-surface silicate rock weathering by adding crushed basalt in a range of field conditions and by measuring the increase in dissolved elemental fluxes, compared with adjacent controls. Silicate weathering consumes protons from carbonic acid in equilibrium with atmospheric CO2, releasing Ca2+and Mg2+ ions into solution and producing a shift to higher pH, favouring bicarbonate ion formation. These ions are transported via runoff, shallow soil flow and land-drains to rivers, ultimately to provide an enhanced thermodynamic drive for oceanic carbonate precipitation (permanent carbon storage).
This project will evaluate the rates of basalt weathering as a function of soil type and land use to determine if weathering rates can be accelerated sufficiently to consume atmospheric CO2 on short timescales. Co-benefits of using basalt as a soil amendment (partial avoidance of CO2 emission from the use of Aglime, increased oceanic alkalinity, enhanced availability of P and other critical plant nutrients) will also be investigated.

Report