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Research about Guatemala

Source-linked reports with geographic coverage including Guatemala.

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Geology and geothermal potential of the Tecuamburro Volcano area, Guatemala

Tecuamburro, an andesitic stratovolcano in southeastern Guatemala, is within the chain of active volcanoes of Central America. Though Tecuamburro has no record of historic eruptions, radiocarbon ages indicate that eruption of this and three other adjacent volcanoes occurred within the past 38,300 years. The youngest eruption produced a dacite dome. Moreover, powerful steam explosions formed a 250 m wide crater about 2900 years ago near the base of this dome. The phreatic crater contains a pH-3 thermal lake. Fumaroles are common along the lake shore, and several other fumaroles are located nearby. Neutral-chloride hot springs are at lower elevations a few kilometers away. All thermal manifestations are within an area of about 400 km 2 roughly centered on Tecuamburro Volcano. Thermal implications of the volume, age, and composition of the post-38.3 ka volcanic rocks suggest that magma, or recently solidified hot plutons, or both are in the crust beneath these lavas. Chemical geothermometry carried out by other workers suggests that a hydrothermal-convection system is centered over this crustal heat source. Maximum temperatures of about 300°C are calculated for samples collected in the area of youngest volcanism, whereas samples from outlying thermal manifestations yield calculated temperatures ≤ <- 165° C "> 165°C . An 808 m deep drill hole completed in 1990 to partly test the geothermal model developed from surface studies attained a maximum temperature of almost 240°C. Thus, the possibility of a commercial-grade hydrothermal resource in the area seems high.

Tecuamburro Volcano↗

Hydrogeochemical exploration of geothermal prospects in the Tecuamburro Volcano region, Guatemala

Chemical and isotopic analyses of thermal and nonthermal waters and of gases from springs and fumaroles are used to evaluate the geothermal potential of the Tecuamburro Volcano region, Guatemala. Chemically distinct geothermal surface manifestations generally occur in separate hydrogeologic areas within this 400 km 2 region: low-pressure fumaroles with temperatures near local boiling occur at 1470 m elevation in a sulfur mine near the summit of Tecuamburro Volcano; non-boiling acid-sulfate hot springs and mud pots are restricted to the Laguna Ixpaco area, about 5 km NNW of the sulfur mine and 350–400 m lower in elevation; steam-heated and thermal-meteoric waters are found on the flanks of Tecuamburro Volcano and several kilometers to the north in the andesitic highland, where the Infernitos fumarole (97°C at 1180 m) is the primary feature; neutral-chloride hot springs discharge along Rio Los Esclavos, principally near Colmenares at 490 m elevation, about 8–10 km SE of Infernitos. Maximum geothermometer temperatures calculated from Colmenares neutral-chloride spring compositions are ~ ∼180° C "> 180°C , whereas maximum subsurface temperatures based on Laguna Ixpaco gas compositions are ~ ∼310° C "> 310°C . An exploration core hole drilled to a depth of 808 m about 0.3 km south of Laguna Ixpaco had a bottom-hole temperature of 238°C but did not produce sufficient fluids to confirm or chemically characterize a geothermal reservoir. Hydrogeochemical data combined with regional geologic interpretations indicate that there are probably two hydrothermal-convection systems, which are separated by a major NW-trending structural boundary, the Ixpaco fault. One system with reservoir temperatures near 300°C lies beneath Tecuamburro Volcano and consists of a large vapor zone that feeds steam to the Laguna Ixpaco area, with underlying hot water that flows laterally to feed a small group of warm, chloriderich springs SE of Tecuamburro Volcano. The other system is located beneath the Infernitos area in the andesitic highland and consists of a lower-temperature (150–190°C) reservoir with a large natural discharge that feeds the Colmenares hot springs.

Tecuamburro Volcano↗

Tecuamburro Volcano, Guatemala: Exploration geothermal gradient drilling and results

Results of geological, volcanological, hydrogeochemical, and geophysical field studies conducted in 1988 and 1989 at the Tecuamburro geothermal site, Guatemala, indicate that there is a substantial shallow heat source beneath the area of youngest volcanism. Gases from acid-sulfate springs near Laguna Ixpaco consistently yield maximum estimated subsurface temperatures of 300°C. To obtain information on subsurface temperatures and temperature gradients, stratigraphy, fracturing, hydrothermal alteration, and hydrothermal fluids, a geothermal gradient core hole (TCB-1) was drilled to 808 m low on the northern flank of the Tecuamburro Volcano complex. The hole is located 300 m south of a 300m-diameter phreatic crater. Laguna Ixpaco, dated at 2910 years. TCB-1 temperature logs do not indicate isothermal conditions at depth and the calculated thermal gradient from 500–800 m is 230°C/km. Bottom hole temperature is close to 240°C. Calculated heat flow values are around 350–400 mW/m 2 . Fluid-inclusion and secondary-alteration studies indicate that veins and secondary minerals were formed at temperatures equal to or slightly less than present temperatures; thus, the Tecuamburro geothermal system may still be heating up. The integration of results from the TCB-1 gradient core hole with results from field studies provides strong evidence that the Tecuamburro area holds great promise for geothermal resource development.

Tecuamburro Volcano↗

Geochemical evaluation of the geothermal resources in the San Marcos region, Guatemala

The chemical and isotopic compositions of hot springs in the San Marcos region of Guatemala are internally consistent with a hydrologic model in which a deep 240°C reservoir and one or more shallow 195–200°C reservoirs are present. Variations in hot-spring water compositions results from a combination of boiling, mixing with cold, dilute water, and chemical re-equilibration with decreasing temperature. The recharge water for the deep 240°C reservoir is isotopically heavier than the local meteoric water and probably comes from many kilometers to the west or southwest. The water in the shallow reservoir is a mixture of the 240°C water with about 20 ± 5% of cold, locally derived meteoric water. After mixing, the water in the shallow reservoir re-equilibrates with reservoir rock at 195–200°C. In some places additional mixing with cold water occurs after water leaves the shallow reservoir.

San Marcos region↗

X-ray mineralogy of cores from two Guatemalan caldera lakes

The U.S. Geological Survey (USGS), under the sponsorship of The Agency for International Development, in cooperation with Dartmouth College, collected 13 cores to study the sedimentation in two Guatemalan cauldera lakes, Atitlan and Ayarza.

Lake Atitlan;Lake Ayarza↗

Preliminary catalog of aftershocks of the Guatemala earthquake of February 4, 1976, from the area between Guatemala City and Lake Atitlan

A six-station seismic network, about 140 km in diameter, has been operated just west of Guatemala City since March 1975, as part of a cooperative project between the U.S. Geological Survey and the Institute Nacional de Sismologia, Vulcanologia, Meteorologia e Hidrologia (INSIVUMEH), of Guatemala. The purpose of this project was to monitor the seismicity near the active volcanoes Pacaya and Fuego bait the seismic stations were well situated to record several thousand aftershocks from the magnitude 7.5 (Ms) Guatemalan earthquake of February 4, 1976. This catalog contains hypocentral data on 1560 of these events from selected time frames between February 5 and June 30, 1976.

area between Guatemala City and Lake Atitlan↗

Documentation for alinement arrays, Motagua fault, Guatemala

The following brief report documents the locations and surveying data for four alinement arrays (fig. 1, p.-7-19) across the Motagua fault, Guatemala, which were installed to measure afterslip occurring along the fault. The arrays represent new monuments installed in areas where displacements had been measured as early as four days after the earthquake. The results of those measurements are reported by Bucknam and others (1978). Because of lack of monument stability, the susceptibility to damage of the various monuments used in the earlier work, and the need for more precise measurements because of decreasing rate of slip, the new monuments were installed at the four sites in May 1978.

Motagua fault↗