Crystallization pressure versus “crack seal” as the mechanism for banded veins

Research Article| January 01, 2001 Crystallization pressure versus "crack seal" as the mechanism for banded veins David V. Wiltschko; David V. Wiltschko 1Department of Geology and Geophysics and Center for Tectonophysics, Texas A&M University, College Station, Texas 77843, USA Search for other works by this author on: GSW Google Scholar John W. Morse John W. Morse 2Departments of Oceanography and Geology and Geophysics, Texas A&M University, College Station, Texas 77843, USA Search for other works by this author on: GSW Google Scholar Geology (2001) 29 (1): 79–82. https://doi.org/10.1130/0091-7613(2001)029<0079:CPVCSA>2.0.CO;2 Article history received: 08 Jun 2000 rev-recd: 06 Oct 2000 accepted: 06 Oct 2000 first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation David V. Wiltschko, John W. Morse; Crystallization pressure versus "crack seal" as the mechanism for banded veins. Geology 2001;; 29 (1): 79–82. doi: https://doi.org/10.1130/0091-7613(2001)029<0079:CPVCSA>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Banded fibrous veins are often pointed to as evidence for episodic crack opening driven by oscillations in fluid pressure or bulk strain. Advances in understanding the geochemistry of precipitation, data on veins, and experiments suggest that pressure due to growing crystals may be an alternate explanation for many observations on these types of veins. We propose that some veins originate at sites of precipitation and then propagate due to the pressure exerted by the crystal growth. As materials precipitate, the vein walls are pushed apart. The resulting veins have shapes typical for mode I cracks except that, mechanically, crystallization pressure replaces the role of internal fluid pressure in their propagation. A nonzero remote differential stress serves to align veins. Mechanical and geochemical considerations suggest that this process will be most important in fine-grained rocks such as greenschist-grade pelites where diffusion from sites of dissolution rather than advection is the dominant mass-transport process. Veins may owe their orientation to tectonism, but their initiation and growth are due to processes that supersaturate the pore fluid. Veins formed by this mechanism involve cracking to the extent that precipitation forces an original flaw to extend during precipitation. Cyclic quartz-mica bands may indicate geochemical self-organization at the vein wall driven by pressure-solution-enhanced supersaturation in the pore fluid and nonlinear precipitation kinetics at the vein wall. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.