The hydrothermal system of Nevado del Ruiz Volcano, Colombia

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:5698143

Lopez, D A.L.

Nevado del Ruiz is an andesitic stratovolcano located 150 km northwest of Bogota, Columbia characterized by a large hydrothermal system with two very distinctive types of water: acid sulfate waters, and bicarbonate and neutral chloride waters. The waters within each group fall in well-defined lines on compositional cross plots with an apparent lack of mixing between the two water types. The acid sulfate waters appear to be related to the north-west striking and seismically active Villamaria-Termales fault. The neutral chloride waters are clustered to the west and south-east of the volcano. The bicarbonate waters are more widespread. Several hydrothermally-altered samples from Nevado del Ruiz volcano hydrothermal system were analyzed using X-ray diffraction techniques. It was possible to distinguish two sets of mineral assemblages which correspond to the two water types. The acid sulfate waters produce cristobalite, sulfates, hematite or pyrite, sulfur and minor amounts of trydimite, kaolinite, smectite, and illite. The alteration products at the neutral chloride and bicarbonate waters include mainly carbonates and cristobalite. Simulation of the reaction between the hydrothermal fluids and the basaltic andesites of the lower volcanic units at Ruiz using the computer program CHILLER yielded mineral assemblages which are consistent with the observed alteration mineralogy. High chloride and sulfate concentrations, and helium and sulfur isotopes suggest that the acid sulfate waters have an important magmatic contribution. The composition of the neutral chloride an bicarbonate waters suggests mineral equilibria with feldspars and carbonates. Both types of waters appear to be the product of mixing of high salinity end members with different proportions of meteoric water. Linear variations in composition of the gases discharged at Ruiz suggested that the gas phase also represents mixing. Faults and contacts play a key role in the circulation of fluids at Ruiz.

• Research Organization: Louisiana State Univ. and Agricultural and Mechanical Coll., Baton Rouge, LA (United States)
• OSTI ID: 5698143
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
58 GEOSCIENCES
GEOTHERMAL FLUIDS
QUALITATIVE CHEMICAL ANALYSIS
VOLCANOES
HYDROTHERMAL SYSTEMS
ACID CARBONATES
ACID SULFATES
ANDESITES
C CODES
CHLORIDES
COLOMBIA
COMPUTERIZED SIMULATION
GEOCHEMISTRY
MINERALOGY
VOLCANIC ROCKS
WATER CHEMISTRY
CHEMICAL ANALYSIS
CHEMISTRY
CHLORINE COMPOUNDS
COMPUTER CODES
DEVELOPING COUNTRIES
ENERGY SYSTEMS
FLUIDS
GEOTHERMAL SYSTEMS
HALIDES
HALOGEN COMPOUNDS
IGNEOUS ROCKS
LATIN AMERICA
OXYGEN COMPOUNDS
ROCKS
SIMULATION
SOUTH AMERICA
SULFATES
SULFUR COMPOUNDS
152001* - Geothermal Data & Theory- Properties of Aqueous Solutions
580000 - Geosciences