Horst and Graben
From Open Energy Information
Horst and Graben:
Topographic features found in a normal fault zone forming ridges and valleys. A graben represents a block of land that has dropped down relative to the landscape and a horst represents a block of land remaining higher than the general landscape.
Topographic Features
List of topographic features commonly encountered in geothermal resource areas:
A "horst and graben" is a crustal-extension structure, composed of a series of normal faults, typical of the Basin & Range region of the US and Turkey’s West Anatolian Extensional Province. From the surface they appear as a series of ridges (horsts) and valleys (grabens) that run perpendicular to the direction of extension.
Crustal extension results in horst and graben topography. Arrows indicate direction of extension. Image modified by Gregors for use on wikipedia, from an original U.S. Geological Survey Earthquake Glossary figure.
Extensional tectonics in the Basin and Range province cover Nevada almost entirely in horst and graben structures. They appear at the surface as a series of ridges and valleys oriented perpendicular to the direction of extension. (reference: http://www.fas.org/irp/imint/docs/rst/Sect6/Sect6_8.html)
Examples
Want to add an example to this list? Select a Geothermal Resource Area to edit its "Topographic Features" property using the "Edit with Form" option.
CSV| Geothermal Resource Area | Geothermal Region | Tectonic Setting | Host Rock Age | Host Rock Lithology | Mean Capacity | Mean Reservoir Temp |
|---|---|---|---|---|---|---|
| Amedee Geothermal Area | Walker-Lane Transition Zone | Extensional Tectonics | Mesozoic | granite; granodiorite | ||
| Beowawe Hot Springs Geothermal Area | Central Nevada Seismic Zone Geothermal Region | Extensional Tectonics | Ordovician | shale; quartzite | 17 MW 17,000 kW 17,000,000 W 17,000,000,000 mW 0.017 GW 1.7e-5 TW | 483.15 K 210 °C 410 °F 869.67 °R |
| Blue Mountain Geothermal Area | Northwest Basin and Range Geothermal Region | Extensional Tectonics | Triassic | Metasedimentary | 49.5 MW 49,500 kW 49,500,000 W 49,500,000,000 mW 0.0495 GW 4.95e-5 TW | 470.15 K 197 °C 386.6 °F 846.27 °R |
| Brady Hot Springs Geothermal Area | Northwest Basin and Range Geothermal Region | Extensional Tectonics | Mesozoic | metamorphic rocks | 26.1 MW 26,100 kW 26,100,000 W 26,100,000,000 mW 0.0261 GW 2.61e-5 TW | 455.15 K 182 °C 359.6 °F 819.27 °R |
| Coso Geothermal Area | Walker-Lane Transition Zone | Extensional Tectonics | Mesozoic | granitic | 300 MW 300,000 kW 300,000,000 W 300,000,000,000 mW 0.3 GW 3.0e-4 TW | 571.15 K 298 °C 568.4 °F 1,028.07 °R |
| Desert Peak Geothermal Area | Northwest Basin and Range Geothermal Region | Extensional Tectonics | Mesozoic | greenstone | 23 MW 23,000 kW 23,000,000 W 23,000,000,000 mW 0.023 GW 2.3e-5 TW | 481.15 K 208 °C 406.4 °F 866.07 °R |
| Dixie Valley Geothermal Area | Central Nevada Seismic Zone Geothermal Region | Extensional Tectonics | Jurassic | Basalt | 62 MW 62,000 kW 62,000,000 W 62,000,000,000 mW 0.062 GW 6.2e-5 TW | 504.15 K 231 °C 447.8 °F 907.47 °R |
| Fenton Hill HDR Geothermal Area | Rio Grande Rift | Extensional Tectonics Rift Zone | Precambrian | Crystalline basement “pCu” (undifferentiated in map units); Biotite Granodiorite (Phase I Reservoir); Gneiss, Schist, Granodiorite, Granite, Metavolcanic Rocks (Phase II Reservoir) | 20 MW 20,000 kW 20,000,000 W 20,000,000,000 mW 0.02 GW 2.0e-5 TW | 508.15 K 235 °C 455 °F 914.67 °R |
| Germencik Geothermal Area | Aegean-West Anatolian Extensional Region | Extensional Tectonics | Marble | 73.4 MW 73,400 kW 73,400,000 W 73,400,000,000 mW 0.0734 GW 7.34e-5 TW | 491.15 K 218 °C 424.4 °F 884.07 °R | |
| Gumuskoy Geothermal Area | Aegean-West Anatolian Extensional Region | Extensional Tectonics Strike-Slip | Paleozic | Marble | 13.2 MW 13,200 kW 13,200,000 W 13,200,000,000 mW 0.0132 GW 1.32e-5 TW | 413.15 K 140 °C 284 °F 743.67 °R |
| Kizildere Geothermal Area | Aegean-West Anatolian Extensional Region | Extensional Tectonics | Miocene | Limestone | 102 MW 102,000 kW 102,000,000 W 102,000,000,000 mW 0.102 GW 1.02e-4 TW | 459.15 K 186 °C 366.8 °F 826.47 °R |
| Lightning Dock Geothermal Area | Southern Basin and Range Geothermal Region | Extensional Tectonics | Paleozoic carbonate rocks and late Tertiary volcanic rocks | 4.4 MW 4,400 kW 4,400,000 W 4,400,000,000 mW 0.0044 GW 4.4e-6 TW | 443.15 K 170 °C 338 °F 797.67 °R | |
| Long Valley Caldera Geothermal Area | Walker-Lane Transition Zone | Extensional Tectonics | Quaternary | Bishop Tuff, Metamorphic Basement | 38 MW 38,000 kW 38,000,000 W 38,000,000,000 mW 0.038 GW 3.8e-5 TW | 513.15 K 240 °C 464 °F 923.67 °R |
| Neal Hot Springs Geothermal Area | Snake River Plain | Extensional Tectonics | Miocene | Basalt | 33 MW 33,000 kW 33,000,000 W 33,000,000,000 mW 0.033 GW 3.3e-5 TW | 429.15 K 156 °C 312.8 °F 772.47 °R |
| Raft River Geothermal Area | Northern Basin and Range Geothermal Region | Extensional Tectonics | 1- Archean; 2-Proterozoic | 1- quartz monzonite; 2-schist; quartzite | 13 MW 13,000 kW 13,000,000 W 13,000,000,000 mW 0.013 GW 1.3e-5 TW | 468.15 K 195 °C 383 °F 842.67 °R |
| Salavatli Geothermal Area | Aegean-West Anatolian Extensional Region | Extensional Tectonics | 58 MW 58,000 kW 58,000,000 W 58,000,000,000 mW 0.058 GW 5.8e-5 TW | 444.15 K 171 °C 339.8 °F 799.47 °R | ||
| Salt Wells Geothermal Area | Northwest Basin and Range Geothermal Region | Extensional Tectonics | 23.6 MW 23,600 kW 23,600,000 W 23,600,000,000 mW 0.0236 GW 2.36e-5 TW | 466.15 K 193 °C 379.4 °F 839.07 °R | ||
| San Emidio Desert Geothermal Area | Northwest Basin and Range Geothermal Region | Extensional Tectonics | 14.22 MW 14,220 kW 14,220,000 W 14,220,000,000 mW 0.0142 GW 1.422e-5 TW | 426.15 K 153 °C 307.4 °F 767.07 °R | ||
| Soda Lake Geothermal Area | Northwest Basin and Range Geothermal Region | Extensional Tectonics | Miocene | pumice tuff | 26.1 MW 26,100 kW 26,100,000 W 26,100,000,000 mW 0.0261 GW 2.61e-5 TW | 452.15 K 179 °C 354.2 °F 813.87 °R |
| Steamboat Springs Geothermal Area | Walker-Lane Transition Zone | Extensional Tectonics | 1- Cretaceous; 2- Pliocene-Pleistocene | 1- granodiorite; 2- basaltic andesite | 147 MW 147,000 kW 147,000,000 W 147,000,000,000 mW 0.147 GW 1.47e-4 TW | 483.15 K 210 °C 410 °F 869.67 °R |
| Stillwater Geothermal Area | Northwest Basin and Range Geothermal Region | Extensional Tectonics | Quaternary | sandstone | 47.2 MW 47,200 kW 47,200,000 W 47,200,000,000 mW 0.0472 GW 4.72e-5 TW | 447.15 K 174 °C 345.2 °F 804.87 °R |
| Takigami Geothermal Area | Ryuku Arc | Extensional Tectonics Subduction Zone | Tertiary | Andesite | 28 MW 28,000 kW 28,000,000 W 28,000,000,000 mW 0.028 GW 2.8e-5 TW | 478.15 K 205 °C 401 °F 860.67 °R |
| Valles Caldera - Redondo Geothermal Area | Rio Grande Rift | Extensional Tectonics Rift Zone | Mississippian-Pennsylvanian; Pleistocene, 1.6 to 1.25 Ma | Limestone-Madera Formation “MIPu”; Rhyolitic tuff-Intracaldera Bandelier Tuff (upper Tshirege “Qbt” and lower Otowi “Qbo” members); Caldera Fill Rhyolite (shallow) | ||
| Valles Caldera - Sulphur Springs Geothermal Area | Rio Grande Rift | Extensional Tectonics Rift Zone | Precambrian; Mississippian-Pennsylvanian; Pleistocene, 1.6 to 1.25 Ma; Pliocene; Miocene | Crystalline basement “pCu”; Limestone-Madera Formation “MIPu”; Rhyolitic tuff-Bandelier Tuff (upper Tshirege “Qbt” and lower Otowi “Qbo” members); Caldera Fill Rhyolite (shallow); Dacitic/Andesitic to Rhyolitic lavas and tuffs-Keres Group Volcanics (shallow); Santa Fe Group volcaniclastics “Tsf” | ||
| Wabuska Hot Springs Geothermal Area | Walker-Lane Transition Zone Geothermal Region | Extensional Tectonics | Quaternary | gravels; sands | 2.4 MW 2,400 kW 2,400,000 W 2,400,000,000 mW 0.0024 GW 2.4e-6 TW | 403.15 K 130 °C 266 °F 725.67 °R |