Geologic Map of Los Humeros volcanic complex and geothermal field, eastern Trans-Mexican Volcanic Belt

We present an updated version of the geologic map of Los Humeros Volcanic Complex (LHVC) and geothermal field, based on acomplete revised characterization of the rock units and contacts, structural features, stratigraphy and recent radiometric dating withmodern methods (U/Th, 40Ar/39Ar, Carrasco-Núñez et al., 2017, in press), together with the use of high resolution Digital TerrainModel at 1m resolution and Google Earth optical imagery. Improvements of this version include refined stratigraphic sequence,revised classification of each lithostratigraphic unit, updated structural features and geochronologic data; all together providingconstraints to support a new evolutionary volcanic history for LHVC. Main changes with previous works involve the recently dis-covery of much younger ages for the main caldera-forming eruption. Much younger ages were also obtained for other importantexplosive phases. These findings reveal the existence of a much younger long-lived magmatic system with Holocene activity and ahigh geothermal potential that requires a further assessment for exploration and volcanic hazard purposes.

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Anatomy of the magmatic plumbing system of Los Humeros Caldera (Mexico): implications for geothermal systems

10.5194/se-2019-86 ◽

2019 ◽

Author(s):

Federico Lucci ◽

Gerardo Carrasco-Núñez ◽

Federico Rossetti ◽

Thomas Theye ◽

John C. White ◽

...

Keyword(s):

Volcanic Belt ◽

Mineral Chemistry ◽

Volcanic Complex ◽

Geothermal Systems ◽

Plumbing System ◽

Geothermal Exploration ◽

Geothermal Fields ◽

Mexican Volcanic Belt ◽

Plumbing Systems ◽

Magmatic Plumbing System

Abstract. Understanding the anatomy of magma plumbing systems of active volcanoes is essential not only for unraveling magma dynamics and eruptive behaviors, but also to define the geometry, depth and temperature of the heat sources for geothermal exploration. The Pleistocene-Holocene Los Humeros volcanic complex is part of the Eastern Trans-Mexican Volcanic Belt (Central Mexico) and it represents one of the most important exploited geothermal fields in Mexico with ca. 90 MW of produced electricity. A field-based petrologic and thermobarometric study of lavas erupted during the Holocene (post-Caldera stage) has been performed with the aim to decipher the anatomy of the magmatic plumbing system existing beneath the caldera. New petrographical, whole rock major element data and mineral chemistry were integrated within a suite of inverse thermobarometric models. Compared with previous studies where a single voluminous melt-controlled magma chamber (or "Standard Model") at shallow depths was proposed, our results support a more complex and realistic scenario characterized by a heterogeneous multilayered system comprising a deep (ca. 30 km) basaltic reservoir feeding progressively shallower and smaller distinct stagnation layers, pockets and batches up to very shallow conditions (1 kbar, ca. 3 km). Evolution of melts in the feeding system is mainly controlled by differentiation processes via fractional crystallization, as recorded by polybaric crystallization of clinopyroxenes and orthopyroxenes. Moreover, this study attempts to emphasize the importance to integrate field-petrography, texture observations and mineral chemistry of primary minerals to unravel the pre-eruptive dynamics and therefore the anatomy of the plumbing system beneath an active volcanic complex, which notwithstanding the numerous existing works is still far to be well understood. A better knowledge of the heat source feeding geothermal systems is very important to improve geothermal exploration strategies.

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Subsurface stratigraphy and its correlation with the surficial geology at Los Humeros geothermal field, eastern Trans-Mexican Volcanic Belt

Geothermics ◽

10.1016/j.geothermics.2017.01.001 ◽

2017 ◽

Vol 67 ◽

pp. 1-17 ◽

Cited By ~ 26

Author(s):

G. Carrasco-Núñez ◽

M. López-Martínez ◽

J. Hernández ◽

V. Vargas

Keyword(s):

Volcanic Belt ◽

Geothermal Field ◽

Surficial Geology ◽

Mexican Volcanic Belt ◽

Trans Mexican Volcanic Belt

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The Pliocene Xoconostle high sulfidation epithermal deposit in the Trans-Mexican Volcanic Belt: Preliminary study

Boletín de la Sociedad Geológica Mexicana ◽

10.18268/bsgm2020v72n3a260520 ◽

2020 ◽

Vol 72 (3) ◽

pp. A260520

Author(s):

Edith Fuentes-Guzmán ◽

Antoni Camprubí ◽

Janet Gabites ◽

Eduardo González-Partida ◽

Vanessa Colás

Keyword(s):

Regional Scale ◽

Volcanic Belt ◽

Structural Features ◽

Epithermal Deposit ◽

Metallogenic Province ◽

High Sulfidation ◽

South Central ◽

Mexican Volcanic Belt ◽

Trans Mexican Volcanic Belt ◽

Good Agreement

The Xoconostle prospect in northeastern Michoacán state, south-central Mexico, is constituted by high sulfidation epithermal breccias and stockworks with Au and Hg prospective anomalies. The mineralization is hosted by latest Miocene to Pliocene rocks grouped into the El Terrero ignimbrite and the Siete Cruces dome complex and a stock of intermediate composition and undetermined (Pliocene?) age. Two alunite samples from deep hypogene advanced argillic alteration assemblages within the deposit yielded 40Ar/39Ar ages at 5.57 ± 0.44 (Messinian) and 3.67 ± 0.20 Ma (Zanclean). Such ages are in good agreement with those of volcanic rocks at a semi-regional scale, especially those associated with the nearby Amealco caldera. Assuming that the formation of Xoconostle deposit could be genetically related to any of the eruptive units in this caldera, it would be associated with dacitic-andesitic rocks at ~4.7 Ma or with bimodal andesite-basalt volcanism at ~3.7 Ma, with which rhyolites at the southwest rim of the caldera (nearer to the epithermal deposit) are contemporaneous. The obtained ages are also in good agreement with those determined for the youngest stages in the evolution of the Trans-Mexican Volcanic Belt (TMVB). In addition, such ages compare well with those established for the E-W striking Morelia-Acambay normal fault zone (or Acambay graben). The occurrence of E-W structural features in the study area support their correlation with those in the Acambay graben. Although the metallogenesis of the TMVB needs further endeavours that contribute to its understanding, the Xoconostle prospect adds up to other dated magmatic-hydrothermal deposits that may collectively constitute a Pliocene metallogenic province whose inception was geologically circumscribed to this volcanic arc. However, this and its companion papers in this issue confirm the metallogenic potential of the TMVB in most of its stages of evolution, particularly in the late Miocene-Pliocene stage of acid and bimodal volcanism.

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Anatomy of the magmatic plumbing system of Los Humeros Caldera (Mexico): implications for geothermal systems

Solid Earth ◽

10.5194/se-11-125-2020 ◽

2020 ◽

Vol 11 (1) ◽

pp. 125-159 ◽

Cited By ~ 7

Author(s):

Federico Lucci ◽

Gerardo Carrasco-Núñez ◽

Federico Rossetti ◽

Thomas Theye ◽

John Charles White ◽

...

Keyword(s):

Volcanic Belt ◽

Mineral Chemistry ◽

Geothermal Field ◽

Volcanic Complex ◽

Geothermal Systems ◽

Plumbing System ◽

Geothermal Fields ◽

Plumbing Systems ◽

Magmatic Plumbing System ◽

Deep Depth

Abstract. Understanding the anatomy of magma plumbing systems of active volcanoes is essential not only for unraveling magma dynamics and eruptive behaviors but also to define the geometry, depth, and temperature of the heat sources for geothermal exploration. The Pleistocene–Holocene Los Humeros volcanic complex is part of the eastern Trans-Mexican Volcanic Belt (central Mexico), and it constitutes one of the most important exploited geothermal fields in Mexico with ca. 90 MW of produced electricity. With the aim to decipher the anatomy (geometry and structure) of the magmatic plumbing system feeding the geothermal field at Los Humeros, we carried out a field-based petrological and thermobarometric study of the exposed Holocene lavas. Textural analysis, whole-rock major-element data, and mineral chemistry are integrated with a suite of mineral-liquid thermobarometric models. Our results support a scenario characterized by a heterogeneous multilayered system, comprising a deep (depth of ca. 30 km) basaltic reservoir feeding progressively shallower and smaller discrete magma stagnation layers and batches, up to shallow-crust conditions (depth of ca. 3 km). The evolution of melts in the feeding system is mainly controlled by differentiation processes through fractional crystallization (plagioclase + clinopyroxene + olivine + spinel). We demonstrate the inadequacy of the existing conceptual models, where a single voluminous melt-controlled magma chamber (or “Standard Model”) at shallow depths was proposed for the magmatic plumbing system at Los Humeros. We instead propose a magmatic plumbing system made of multiple, more or less interconnected, magma transport and storage layers within the crust, feeding small (ephemeral) magma chambers at shallow-crustal conditions. This revised scenario provides a new configuration of the heat source feeding the geothermal reservoir at Los Humeros, and it should be taken into account to drive future exploration and exploitation strategies.

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Comment on Estimating the depth and evolution of intrusions at resurgent calderas: Los Humeros (Mexico) by Urbani et al. (2020)

10.5194/se-2020-110 ◽

2020 ◽

Author(s):

Gianluca Norini ◽

Gianluca Groppelli

Keyword(s):

Field Data ◽

Morphological Analysis ◽

Temporal Evolution ◽

Geothermal Field ◽

Radiometric Dating ◽

Volcanic Complex ◽

Caldera Floor ◽

Magmatic Intrusions ◽

Intrusion Depth ◽

Emplacement Depth

Abstract. A multiple magmatic intrusions model has been proposed by Urbani et al. (2020) for the resurgence of the Los Potreros caldera floor, in the Los Humeros Volcanic Complex. This model predicts (1) the occurrence of few localized bulges in the otherwise not deformed caldera floor, and (2) that the faults corresponding to different bulges exhibit different spatial and temporal evolution. Already available field data from easily accessible outcrops and a simple morphological analysis show that these two conditions are not met at Los Potreros caldera. Also, a geothermal well (H4), located in the most recent supposed bulge for which Urbani et al. (2020) calculated an intrusion depth (Loma Blanca, intrusion depth of 425 ± 170 m), doesn't show any thermal and lithological evidence of such a shallow cryptodome. Finally, already published stratigraphic data and radiometric dating apparently disprove the proposed correlation between extruded viscous lavas and faulting. Thus, even if recent shallow intrusions may exist in the area, Urbani et al. (2020) fails to provide any useful information on their occurrence, location, age, emplacement depth, role in the resurgence of the Los Potreros caldera floor, and influence on the structure of the Los Humeros geothermal field.

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Anatomy of the Xáltipan ignimbrite at Los Humeros Volcanic Complex; the largest eruption of the Trans-Mexican Volcanic Belt

Journal of Volcanology and Geothermal Research ◽

10.1016/j.jvolgeores.2019.106755 ◽

2020 ◽

Vol 392 ◽

pp. 106755

Author(s):

Jaime Alberto Cavazos-Álvarez ◽

Gerardo Carrasco-Núñez

Keyword(s):

Volcanic Belt ◽

Volcanic Complex ◽

Mexican Volcanic Belt ◽

Trans Mexican Volcanic Belt

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Wide-Area InSAR Survey of Surface Deformation in Urban Areas and Geothermal Fields in the Eastern Trans-Mexican Volcanic Belt, Mexico

Remote Sensing ◽

10.3390/rs11202341 ◽

2019 ◽

Vol 11 (20) ◽

pp. 2341 ◽

Cited By ~ 4

Author(s):

Francesca Cigna ◽

Deodato Tapete ◽

Víctor Hugo Garduño-Monroy ◽

Jesús Arturo Muñiz-Jauregui ◽

Oscar Humberto García-Hernández ◽

...

Keyword(s):

Land Subsidence ◽

Energy Production ◽

Surface Deformation ◽

Volcanic Belt ◽

Wide Area ◽

Volcanic Complex ◽

Groundwater Pumping ◽

Geothermal Fields ◽

Mexican Volcanic Belt ◽

Trans Mexican Volcanic Belt

This paper provides the first wide-area Interferometric Synthetic Aperture Radar (InSAR) survey of the whole eastern Trans-Mexican Volcanic Belt (42,200 km2). The aims are to identify ground deformation hotspots within major urbanized areas and rural valleys, establish baselines in geothermal exploration sites, and analyze deformation at geothermal exploitation sites and its relationship with energy production. The whole 2003–2010 ENVISAT C-band SAR archive available over the region was processed with the Small BAseline Subset (SBAS) InSAR method to retrieve over 840,000 coherent targets and estimate their ground displacement rates and time series. Land subsidence hotspots due to aquifer drawdown are found within the city of Puebla (up to −53 mm/year vertical rates, groundwater pumping for industrial use), Tlaxcala and Apizaco (−17 mm/year, industrial and public), the valley of Tecamachalco (−22 mm/year, agricultural), Tulancingo (−55 mm/year, public, industrial and agricultural), and in the eastern Mexico City metropolitan area (−44 mm/year, agricultural). The baseline for the Acoculco caldera complex shows widespread ground stability. Conversely, localized subsidence patterns of −5 to −10 mm/year exist around Las Derrumbadas and Cerro Pinto in the Serdán-Oriental basin, due to intense groundwater pumping for agriculture. A well-defined land subsidence area with −11 mm/year maximum rates is found at Los Humeros volcanic complex within Los Potreros collapse, correlating well with energy production infrastructure location and historical steam production rates. Field surveys carried out in Acoculco and Los Humeros in 2018 provide supporting evidence for the identification of hydrothermal manifestations, and understanding of the landscape and surface deformation patterns within the geothermal fields.

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Digital Geologic Cartography and Geochronologic Database of the Trans-Mexican Volcanic Belt and Adjoining Areas

Terra Digitalis ◽

10.22201/igg.terradigitalis.2018.1.34 ◽

2018 ◽

Vol 2 (1) ◽

Cited By ~ 3

Author(s):

Luca Ferrari ◽

Teresa Orozco Esquivel ◽

Mario Navarro ◽

Penélope López-Quiroz ◽

Laura Luna

Keyword(s):

Digital Elevation Models ◽

Volcanic Belt ◽

Geologic Mapping ◽

Volcanic Province ◽

Mexican Volcanic Belt ◽

Digital Elevation ◽

Geologic Map ◽

Trans Mexican Volcanic Belt ◽

Morphological Expression

We present the first interactive digital geologic map of the Trans-Mexican Volcanic Belt (TMVB). The area covered by the cartography span 10° of Longitude (106°- 96° W) and 2°45’ of Latitude (19°-21°45’ N). The geology has been compiled in ArcGIS through an interpretation of all the information available in the literature and integrated with our own geologic mapping. Published maps were digitized from printed copies; when possible, the location of features with clear morphological expression was corrected using digital elevation models within the GIS. The map includes 36 geologic units, faults, volcanic vents, and calderas. The informal geologic units used in the compilation are chronostratigraphic and lithologic and were designed to emphasize the main volcanic episodes that make up this volcanic province. The age assignment for each unit has been cross-checked with a geochronologic database that includes 2009 ages, which can be displayed on the map with access to their attributes. Lithology of each polygon has been also checked against a large geochemical database compiled from the literature.

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