Hydrothermal alteration and fluid inclusion geothermometry of Los Humeros geothermal field, Mexico
- Inst. de Geofisica and DEPFI, UNAM, Cd. Univ., Coyoacan 04510 (MX)
- Geothermal Inst. and Geology Dept., Auckland Univ., Private Bag, Auckland (NZ)
The Los Humeros geothermal field, located in Puebla State, Mexico, occurs in a caldera; drillholes to 3000 m depth encountered a sequence of Quaternary lavas and pyroclastic rocks that range in composition from rhyolite to basalt but are dominantly andesitic. These rest upon the local basement comprising limestone and siltstone of Cretaceous age, which was encountered below 2500 m in the northern part of the field and 1000 m in its southern part. Examination of 29 cores, mostly from below 900 m depth, from 14 wells show that the hydrothermal minerals that occur in the volcanic host rocks include quarts, calcite, epidote, amphibole, sericite, smectite, illite, chlorite, biotite, pyrite and hematite. Their distribution mainly reflects the prevailing hydrological and thermal regime where temperatures locally exceed 300{degrees} C. A preliminary model for the hydrology of the field based upon the hydrothermal alteration mineralogy and fluid inclusion data suggests that dilute hot water ascends via faults in the Central Caldera collapse area of the field and moves laterally outward to elsewhere within the caldera.
- OSTI ID:
- 5791549
- Journal Information:
- Geothermics (International Journal of Geothermal Research and its Applications); (UK), Journal Name: Geothermics (International Journal of Geothermal Research and its Applications); (UK) Vol. 18:5/6; ISSN GTMCA; ISSN 0375-6505
- Country of Publication:
- United States
- Language:
- English
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