Percolation threshold and permeability of crystallizing igneous rocks: The importance of textural equilibrium

Research Article| September 01, 2004 Percolation threshold and permeability of crystallizing igneous rocks: The importance of textural equilibrium M.J. Cheadle; M.J. Cheadle 1Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071, USA Search for other works by this author on: GSW Google Scholar M.T. Elliott; M.T. Elliott 2British Petroleum Exploration (Angola) Ltd., Compass Point, Staines, Middlesex TW18 1DY, UK Search for other works by this author on: GSW Google Scholar D. McKenzie D. McKenzie 3Department of Earth Sciences, Bullard Laboratories, Madingley Road, University of Cambridge, Cambridge CB3 0EZ, UK Search for other works by this author on: GSW Google Scholar Geology (2004) 32 (9): 757–760. https://doi.org/10.1130/G20495.1 Article history received: 26 Jan 2004 rev-recd: 17 May 2004 accepted: 18 May 2004 first online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation M.J. Cheadle, M.T. Elliott, D. McKenzie; Percolation threshold and permeability of crystallizing igneous rocks: The importance of textural equilibrium. Geology 2004;; 32 (9): 757–760. doi: https://doi.org/10.1130/G20495.1 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 The permeability of a crystal mush fundamentally controls the ability of its melt to migrate or segregate with respect to the solid phase and thus controls the extent to which compaction and porous-media convection can occur in crystallizing igneous cumulates. In particular, the existence of a percolation threshold, which defines the porosity at which a crystallizing rock becomes impermeable, can limit the effectiveness of these processes. We present three-dimensional numerical models of the topology of porosity in both texturally equilibrated and nonequilibrated crystal-melt systems; these models enable porosity vs. permeability relationships and hence percolation thresholds to be calculated. The permeability of the nonequilibrated models was calculated using a network-simulation method. These models confirm that there is no percolation threshold for a perfectly texturally equilibrated rock with dihedral angles of <60°. Conversely, the models indicate that the percolation threshold for non–texturally equilibrated rocks is 8%–11%. The models show that permeability is only weakly dependent on the morphology of the crystals at porosities of >20%. These results suggest that the volume of trapped melt in an igneous cumulate may be controlled by the ability of the crystallizing crystal-melt system to reach textural equilibrium. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.