Kinematics of crystal growth in single‐seal syntaxial veins in limestone ‐ a phase‐field study

Späth, M., Spruzeniece, L. , Urai, J. L., Selzer, M., Arndt, M. and Nestler, B. (2021) Kinematics of crystal growth in single‐seal syntaxial veins in limestone ‐ a phase‐field study. Journal of Geophysical Research: Solid Earth, 126(10), e2021JB022. (doi: 10.1029/2021JB022106)

Abstract

Building on recent developments in phase-field modeling of structural diagenesis, we present an analysis of single-seal syntaxial calcite vein microstructure in a variety of limestones. We focus on the effects of fracture aperture, intergranular versus transgranular fracturing, crystal habit and the presence of second phases in the host rock, to systematically investigate a simplified set of models covering the main classes of limestone in 2D. We incorporate the kinematic process of growth competition between differently oriented crystals, growth rate anisotropy between rough and faceted crystal surfaces and different growth rates on intergranular to transgranular fractures. Results show that within the considered parameter space we can reproduce a wide range of vein microstructures in limestone known in nature, such as stretched crystals, wide-blocky veins, and elongated crystals. We identify five archetypes of vein microstructures in limestones, which are diagnostic for different kinematics and evolution of transport processes and illustrate the effect of key parameters in microstructure maps. We show how syntaxial veins with median line form after intergranular fracturing, while stretched crystals indicate transgranular fracturing. Intergranular fracturing leads to stronger growth competition and more prominent CPO in syntaxial veins. Our results can be extended to 3D to include multiple crack-seal events, pore-space cementation and simulation of fluid flow, providing a generic platform for modeling structural diagenesis in limestones.

• Item Type: Articles
• Additional Information: The authors thank German Science Foundation DFG for funding this project, NE 822/34-1, UR 64/17-1. Support for the numerical solution has been contributed through the programs ”RE: 35.14.01” and ”MTET: 38.04.04” of the Helmholtz association. The authors thank Luuk L. Kleipool for help with Limestone nomenclature and for discussions about modelling different limestones. The authors acknowledge support by the state of Baden-Württemberg through bwHPC. The authors thank Julia Gale, John Hooker, and an anonymous reviewer for their constructive reviews. Open access funding enabled and organized by Projekt DEAL.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Spruzeniece, Dr Liene
• Authors: Späth, M., Spruzeniece, L., Urai, J. L., Selzer, M., Arndt, M., and Nestler, B.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: Journal of Geophysical Research: Solid Earth
• Publisher: Wiley American Geophysical Union /
• ISSN: 2169-9313
• Published Online: 04 September 2021
• Copyright Holders: Copyright © 2021 The Author(s)
• First Published: First published in Journal of Geophysical Research: Solid Earth 126(10):e2021JB022106
• Publisher Policy: Reproduced under a creative commons licence
• Data DOI: 10.5281/zenodo.4597529