Chemical controls on the propagation rate of fracture in calcite
[3];
[4];
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Geochemistry Dept.
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Nanosystems Synthesis/Analysis Dept., Center for Integrated Nanotechnologies
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.
- Univ. of New Mexico, Albuquerque, NM (United States). Advanced Materials Lab.
Calcite (CaCO3) is one of the most abundant minerals in the Earth’s crust, and it is susceptible to subcritical chemically-driven fracturing. Understanding chemical processes at individual fracture tips, and how they control the development of fractures and fracture networks in the subsurface, is critical for carbon and nuclear waste storage, resource extraction, and predicting earthquakes. Chemical processes controlling subcritical fracture in calcite are poorly understood. We demonstrate a novel approach to quantify the coupled chemical-mechanical effects on subcritical fracture. The calcite surface was indented using a Vickers-geometry indenter tip, which resulted in repeatable micron-scale fractures propagating from the indent. Individual indented samples were submerged in an array of aqueous fluids and an optical microscope was used to track the fracture growth in situ. The fracture propagation rate varied from 1.6 × 10-8 m s-1 to 2.4 × 10-10 m s-1. The rate depended on the type of aqueous ligand present, and did not correlate with the measured dissolution rate of calcite or trends in zeta-potential. We postulate that chemical complexation at the fracture tip in calcite controls the growth of subcritical fracture. Previous studies indirectly pointed to the zeta-potential being the most critical factor, while our work indicates that variation in the zeta-potential has a secondary effect.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Center for Frontiers of Subsurface Energy Security (CFSES); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC04-94AL85000
- OSTI ID:
- 1492352
- Report Number(s):
- SAND-2018-14261J; 671042
- Journal Information:
- Scientific Reports, Vol. 8, Issue 1; ISSN 2045-2322
- Publisher:
- Nature Publishing GroupCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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