Argillic-Advanced Argillic Alteration

GEOTHERMAL ENERGY

Argillic-Advanced Argillic Alteration:

Hydrothermal alterations in which clay minerals are introduced

Other definitions:Wikipedia Reegle

Relict Geothermal Features

Typical list of modern geothermal features

• Hydrothermally Deposited Rock

• Silica Deposition
• Carbonate Deposition
• Alunite
• Other Hydrothermal Deposits

• Hydrothermally Altered Rock

• Silicification
• Argillic-Advanced Argillic Alteration
• Zeolitic Alteration
• Leach Capping
• Other Hydrothermal Alteration Products

Yelow-whitish rocks denote advanced argillic alteration with abundant alunite. http://cms.unige.ch/sciences/terre/research/Groups/mineral_resources/deposits/deposits_slides_i.php

Argillic and Advanced Argillic alteration are shallow types of alteration encountrered in a variety of different types of hydrothermal systems. Argillic alteration forms at lower temperatures and primarily consists of kaolinite + montmorillonite clay minerals. Advanced Argillic alteration forms at higher temperatures and lower pH conditions (e.g. the acid-steam condensate zone of a hydrothermal system). It consists primarily of kaolinite + dickite clay minerals at lower temperatures and pyrophyllite + andalusite minerals at temperatures > 300°C. Advanced Argillic alteration may also be associated with alunite.

Examples

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CSV

Geothermal Resource Area	Geothermal Region	Control Structure	Host Rock Age	Host Rock Lithology	Mean Capacity	Mean Reservoir Temp
Blue Mountain Geothermal Area	Northwest Basin and Range Geothermal Region	Fault Intersection Intrusion Margins and Associated Fractures	Triassic	Metasedimentary	49.5 MW49,500 kW <br />49,500,000 W <br />49,500,000,000 mW <br />0.0495 GW <br />4.95e-5 TW <br />	470.15 K197 °C <br />386.6 °F <br />846.27 °R <br />
Kizildere Geothermal Area	Aegean-West Anatolian Extensional Region	Fault Intersection	Miocene	Limestone	102 MW102,000 kW <br />102,000,000 W <br />102,000,000,000 mW <br />0.102 GW <br />1.02e-4 TW <br />	459.15 K186 °C <br />366.8 °F <br />826.47 °R <br />
Salt Wells Geothermal Area	Northwest Basin and Range Geothermal Region				23.6 MW23,600 kW <br />23,600,000 W <br />23,600,000,000 mW <br />0.0236 GW <br />2.36e-5 TW <br />	466.15 K193 °C <br />379.4 °F <br />839.07 °R <br />
Valles Caldera - Sulphur Springs Geothermal Area	Rio Grande Rift	Fault Intersection Stratigraphic Boundaries Caldera Rim Margins	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”