Accommodation Zone

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Accommodation Zone

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Accommodation Zone:
Accommodation zones occur at fault intersections consisting of belts of interlocking, oppositely dipping normal faults. Multiple subsurface fault intersections in these zones are a favorable host for geothermal activity.
Other definitions:Wikipedia Reegle


Overlapping, oppositely dipping normal fault systems (accommodation zones) that generate multiple fault intersections in the subsurface. Strike and dip symbols indicate tilt directions of fault blocks. Illustration by James E. Faulds.[1]

Faulds classified accommodation zones as a one of two major subsets of fault intersection types that act as structural controls on geothermal systems in the Basin and Range province of the US.

Fault intersections between normal faults and transversely oriented strike-slip or oblique-slip faults account for 22% of the Basin & Range structures known to host geothermal systems as of 2011. Multiple minor faults in these areas create connections between major structures, allowing fluids to flow through highly fractured dilational quadrants.[1]

Accommodation zones between overlapping, oppositely dipping normal fault systems account for 8% of all Basin & Range structures hosting geothermal systems. Multiple fault intersections in the subsurface in these zones enhances permeability and hydrothermal fluid flow. According to Faulds et al. (2011):

"Accommodation zones in normal fault systems are more prevalent within the extensional terrane that characterizes much of the Great Basin northeast of the Walker Lane.”[1]

Examples

Want to add an example to this list? Select a Geothermal Resource Area to edit its "Controlling Structures" property using the "Edit with Form" button.

CSV
Geothermal
Resource
Area
Geothermal
Region
Tectonic
Setting
Host
Rock
Age
Host
Rock
Lithology
Mean
Capacity
Mean
Reservoir
Temp
Brady Hot Springs Geothermal Area Northwest Basin and Range Geothermal Region Extensional Tectonics Mesozoic metamorphic rocks 26.1 MW26,100 kW
26,100,000 W
26,100,000,000 mW
0.0261 GW
2.61e-5 TW
455.15 K182 °C
359.6 °F
819.27 °R
Stillwater Geothermal Area Northwest Basin and Range Geothermal Region Extensional Tectonics Quaternary sandstone 47.2 MW47,200 kW
47,200,000 W
47,200,000,000 mW
0.0472 GW
4.72e-5 TW
447.15 K174 °C
345.2 °F
804.87 °R

References

  1. 1.0 1.1 1.2 James E. Faulds,Nicholas H. Hinz,Mark F. Coolbaugh,Patricia H. Cashman,Christopher Kratt,Gregory Dering,Joel Edwards,Brett Mayhew,Holly McLachlan. 2011. Assessment of Favorable Structural Settings of Geothermal Systems in the Great Basin, Western USA. In: Transactions. GRC Anual Meeting; 2011/10/23; San Diego, CA. Davis, CA: Geothermal Resources Council; p. 777–783