Implications of perennial saline springs for abnormally high fluid pressures and active thrusting in western California

Journal Article · Fri May 01 04:00:00 EDT 1992 · Geology; (United States)

DOI:https://doi.org/10.1130/0091-7613(1992)020<0431:IOPSSF>2.3.CO;2· OSTI ID:6952025

Unruh, J R; Davisson, M L; Criss, R E; Moores, E M ^[1]

---

1. Univ. of California, Davis (United States)

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 they have had a significant residence time in the subsurface at moderate temperatures. The nonmeteoric character of the springs demonstrates that they are not being fed by perched water tables. The authors propose that these subsurface formation waters are being forced to the surface by anomalously high porefluid 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. They 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.

• OSTI ID: 6952025
• Journal Information: Geology; (United States), Journal Name: Geology; (United States) Vol. 20:5; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ARTESIAN BASINS
CALIFORNIA
CHEMISTRY
DEVELOPED COUNTRIES
FLUID FLOW
GEOCHEMISTRY
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GROUND WATER
HYDROGEN COMPOUNDS
HYDROLOGY
MINERAL SPRINGS
NORTH AMERICA
OXYGEN COMPOUNDS
PORE PRESSURE
SEEPS
SEISMICITY
SEISMOLOGY
USA
WATER
WATER CHEMISTRY
WATER SPRINGS