Research Article| May 01, 1992 Implications of perennial saline springs for abnormally high fluid pressures and active thrusting in western California J. R. Unruh; J. R. Unruh 1Department of Geology, University of California, Davis, California 95616 Search for other works by this author on: GSW Google Scholar M. L. Davisson; M. L. Davisson 1Department of Geology, University of California, Davis, California 95616 Search for other works by this author on: GSW Google Scholar R. E. Criss; R. E. Criss 1Department of Geology, University of California, Davis, California 95616 Search for other works by this author on: GSW Google Scholar E. M. Moores E. M. Moores 1Department of Geology, University of California, Davis, California 95616 Search for other works by this author on: GSW Google Scholar Geology (1992) 20 (5): 431–434. https://doi.org/10.1130/0091-7613(1992)020<0431:IOPSSF>2.3.CO;2 Article history 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 J. R. Unruh, M. L. Davisson, R. E. Criss, E. M. Moores; Implications of perennial saline springs for abnormally high fluid pressures and active thrusting in western California. Geology 1992;; 20 (5): 431–434. doi: https://doi.org/10.1130/0091-7613(1992)020<0431:IOPSSF>2.3.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 Perennial saline springs in the Rumsey Hills area, southwestern Sacramento Valley, California, locally discharge at high elevations and near ridgetops. The springs are cold, are commonly associated with natural gas seeps, and typically emerge along west-vergent thrust faults. Stable isotope analyses indicate that the spring waters are similar to oil-field formation fluids and that they have had a significant residence time in the subsurface at moderate temperatures. The non-meteoric character of the springs demonstrates that they are not being fed by perched water tables. We propose that these subsurface formation waters are being forced to the surface by anomalously high pore-fluid pressures. The Rumsey Hills area is one of Quaternary uplift, thrusting, and crustal shortening, and prospect wells drilled there have encountered anomalously high fluid pressures at shallow depths. We attribute these high fluid pressures to active tectonic compression and shortening of Cretaceous marine sedimentary rocks. The widespread occurrence of anomalously high pore-fluid pressures and perennial saline springs in the Coast Ranges and western Great Valley suggests that much of western California may be characterized as a seismically active, overpressured thrust belt. The emergence of formation waters along thrust faults further suggests that patterns of subsurface fluid flow in western California may be similar to those in overpressured accretionary prisms, and that excess fluid pressures may also play a role in the distribution of seismicity. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.