Leach Capping

GEOTHERMAL ENERGY

Leach Capping:

Zones of acid leaching in which all components of a rock have been removed except for silica

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

Up-flow of acidic hydrothermal fluids break down rocks and form clays at Kerlingarfjoll Geothermal area, Iceland. Photo by Darren Atkins

Often associated with deposition of alunite and bordered by halos of Advanced Argillic Alteration. Leach Cappings are zones of acid leaching in which all components of a rock have been removed except for silica. Such zones are typically encountered near the surface at the zone of principle hydrothermal upflow, where volatile gases condense into shallow groundwater to produce acidic solutions.

Examples

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