On the complex conductivity signatures of calcite precipitation
Article first published online: 5 MAY 2010
Copyright 2010 by the American Geophysical Union.
Journal of Geophysical Research: Biogeosciences (2005–2012)
Volume 115, Issue G2, June 2010
How to Cite
2010), On the complex conductivity signatures of calcite precipitation, J. Geophys. Res., 115, G00G04, doi:10.1029/2009JG001129., , , and (
- Issue published online: 5 MAY 2010
- Article first published online: 5 MAY 2010
- Manuscript Accepted: 22 DEC 2009
- Manuscript Revised: 24 NOV 2009
- Manuscript Received: 24 AUG 2009
- complex conductivity;
- induced polarization;
- electrical double layer;
 Calcite is a mineral phase that frequently precipitates during subsurface remediation or geotechnical engineering processes. This precipitation can lead to changes in the overall behavior of the system, such as flow alternation and soil strengthening. Because induced calcite precipitation is typically quite variable in space and time, monitoring its distribution in the subsurface is a challenge. In this research, we conducted a laboratory column experiment to investigate the potential of complex conductivity as a mean to remotely monitor calcite precipitation. Calcite precipitation was induced in a glass bead (3 mm) packed column through abiotic mixing of CaCl2 and Na2CO3 solutions. The experiment continued for 12 days with a constant precipitation rate of ∼0.6 milimole/d. Visual observations and scanning electron microscopy imaging revealed two distinct phases of precipitation: an earlier phase dominated by well distributed, discrete precipitates and a later phase characterized by localized precipitate aggregation and associated pore clogging. Complex conductivity measurements exhibited polarization signals that were characteristic of both phases of calcite precipitation, with the precipitation volume and crystal size controlling the overall polarization magnitude and relaxation time constant. We attribute the observed responses to polarization at the electrical double layer surrounding calcite crystals. Our experiment illustrates the potential of electrical methods for characterizing the distribution and aggregation state of nonconductive minerals like calcite. Advancing our ability to quantify geochemical transformations using such noninvasive methods is expected to facilitate our understanding of complex processes associated with natural subsurface systems as well as processes induced through engineered treatments (such as environmental remediation and carbon sequestration).