Gravity and seismicity analyses of the El Chichon volcano, Chiapas, Mexico

Medina, F.; González-Morán, Tomas; Gonzalez, Louis

doi:10.1007/bf00876708

Cited by 14 publications

(7 citation statements)

References 15 publications

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“…The Chiapanecan volcanic arc is hosted in the strike-slip fault zone and is oriented 30º oblique and inland in relation to the subducting trench ( Fig. 1A, B; Damon and Motesinos, 1978;Medina et al, 1990;García-Palomo et al, 2004;Mora et al, 2007). The volcanic rocks of the central Chiapanecan volcanic arc (Fig.…”

Section: ; Escandónmentioning

confidence: 99%

Geology and Genesis of the Cerro la Mina Porphyry-High Sulfidation Au (Cu-Mo) Prospect, Mexico

et al. 2017

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The Cerro la Mina Au (Cu-Mo) porphyry-high sulfidation prospect is located in Chiapas State, southeastern Mexico, outside of the major metallogenic provinces of Mexico. The prospect is hosted by Pleistocene alkaline volcanic rocks of the Chiapanecan volcanic arc that formed in a complex triple-junction tectonic setting. Cerro la Mina's stratigraphy comprises pyroclastic flows that were intruded by monzodiorites and diorites at 1.04 ± 0.04 Ma (U-Pb, zircon), and that were overlain by debris flows and synvolcanic trachyandesite domes. The volcanic stratigraphy of Cerro la Mina is dominated by pyroclastic flows and rare basalts that are cut by the Cerro la Mina breccia pipe, a matrix-rich granular, vertically oriented, downward-tapering, polymict lithic rock unit that is host to all of the significant alteration and mineralization. A NW-trending sinistral wrench fault, which was active throughout the history of Cerro la Mina, is responsible for dismembering the prospect after mineralization. The magmatic hydrothermal system was composed of early porphyry-style potassic veins (quartz + K-feldspar ± biotite) and stage 1 pyrite that are preserved in clasts within the breccia pipe, suggesting that brecciation disrupted an embryonic porphyry system. Late potassic alteration occurred after the formation of the breccia pipe, as its matrix is strongly K-feldspar altered. Hydrothermal fluids then produced phyllic alteration composed of quartz, muscovite, illite, illite-smectite, and chlorite that is associated with stage 2 pyrite ± chalcopyrite ± molybdenite ± quartz veins. An unusual zoned pattern of advanced argillic-argillic alteration overprinted potassic and phyllic alteration. This zoning included a low-temperature (<110°C) halloysite + kaolinite that extends from 800 to 250 m below present-day surface and is deeper than higher temperature (>120°C) quartz + dickite ± kaolinite ± pyrophyllite ± alunite that occurs from 250 m to the present-day surface. The advanced argillic-argillic altered rocks host the most significant Au-Cu mineralization, which is associated with stage 3 marcasite, sphalerite, galena, and barite, and stage 4 arsenian pyrite ± enargite ± covellite. The magmatic hydrothermal system at Cerro la Mina began sometime between monzodiorite emplacement (1.04 ± 0.04 Ma; zircon U-Pb) and the precipitation of porphyry stage 2 molybdenite at 780 ± 10 ka (Re-Os). 40 Ar/ 39 Ar dating of biotite (689 ± 13 ka) records the age at which the hydrothermal system cooled below the biotite closure temperature of ~300°C and provides a maximum estimate for the onset of advanced argillicargillic alteration. Sulfur isotope results of sulfides (-2.5 to +4.9‰; mean +0.7‰; n = 20) and a sulfate (barite; +10.5‰; n = 1) suggest a magmatic source of sulfur for all four stages of mineralization. The lack of residual quartz, rare alunite, and anomalous halloysite-kaolinite alteration may be explained by the high acid-buffering capacity of alkaline volcanic host rocks, high CO2 contents of the alkaline magma, and/or potentially by a h...

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Section: ; Escandónmentioning

confidence: 99%

Geology and Genesis of the Cerro la Mina Porphyry-High Sulfidation Au (Cu-Mo) Prospect, Mexico

et al. 2017

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“…Hypocenters and magnitudes were calculated using HYPO-71PC (Lee and Lahr 1978) and the velocity model shown in Table 1. This model was estimated using geologic information of Canul and Rocha (1981) and noticeably reduced the dispersion of epicenters compared with the models of Havskov et al (1983) and Medina et al (1990Medina et al ( , 1992. The model was tested with 30 selected events recorded by at least ten stations after 4 April.…”

Section: Seismic Information and Methods Of Analysismentioning

confidence: 99%

“…Medina et al (1990Medina et al ( , 1992 presented the location of 340 tectonic-type events during April 1982. They also reported the frequency distribution of events during the months of March and April 1982, the variation of the b-value during the same period, and the seismic energy released from 3 to 28 March.…”

Section: Previous Workmentioning

confidence: 99%

“…The general features of the seismicity related to that eruption were reported soon after the eruption and at later dates (Havskov et al 1983;Medina et al 1990;Medina et al 1992;Yokoyama et al 1992); however, the seismic records obtained at that time merit further analysis. In particular, the data provide information on the evolution of the seismicity, especially the change in location of the active zones, the nature of the seismic waveforms, and the temporal variations in both location of foci and characteristics of the seismic signals during the period of activity.…”

Section: Introductionmentioning

confidence: 96%

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Evolution of the seismic activity from the 1982 eruption of El Chichon Volcano, Chiapas, Mexico

Jiménez

Espíndola

1999

Bull Volcanol

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“…The Guayabal tuff cone is situated to the SE of the somma crater and overlies dome rocks (J. L. Macías, personal communication, 2010). According to a regional gravity survey interpreted by Medina et al [1990], the basement uniformly dips SW and residual positive anomalies were detected at the site of the three peripheral domes.…”

Section: Geological Settingsmentioning

confidence: 99%

Geophysical characterization of hydrothermal systems and intrusive bodies, El Chichón volcano (Mexico)

Jutzeler¹,

Varley²,

Roach³

2011

J. Geophys. Res.

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[1] The 1982 explosive eruptions of El Chichón volcano (Chiapas, Mexico) destroyed the inner dome and created a 1-km-wide and 180-m-deep crater within the somma crater. A shallow hydrothermal system was exposed to the surface of the new crater floor and is characterized by an acid crater lake, a geyser-like Cl-rich spring (soap pool), and numerous fumarole fields. Multiple geophysical surveys were performed to define the internal structure of the volcanic edifice and its hydrothermal system. We carried out a high-resolution ground-based geomagnetic survey in the 1982 crater and its surroundings and 38 very low frequency (VLF) transects around the crater lake. A 3-D inversion of the ground-based magnetic data set highlighted three high-susceptibility isosurfaces, interpreted as highly magnetized bodies beneath the 1982 crater floor. Inversion of a digitized regional aeromagnetic map highlighted four major deeply rooted cryptodomes, corresponding to major topographic highs and massive lava dome outcrops outside and on the somma rim. The intracrater magnetic bodies correspond closely to the active hydrothermal vents and their modeled maximum basal depth matches the elevation of the springs on the flanks of the volcano. Position, dip, and vertical extent of active and extinct hydrothermal vents identified by VLF-EM surveys match the magnetic data set. We interpret the shallow lake spring hydrothermal system to be mostly associated with buried remnants of the 550 BP dome, but the Cl-rich soap pool may be connected to a small intrusion emplaced at shallow depth during the 1982 eruption.

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Gravity and seismicity analyses of the El Chichon volcano, Chiapas, Mexico

Cited by 14 publications

References 15 publications

Geology and Genesis of the Cerro la Mina Porphyry-High Sulfidation Au (Cu-Mo) Prospect, Mexico

Geology and Genesis of the Cerro la Mina Porphyry-High Sulfidation Au (Cu-Mo) Prospect, Mexico

Evolution of the seismic activity from the 1982 eruption of El Chichon Volcano, Chiapas, Mexico

Geophysical characterization of hydrothermal systems and intrusive bodies, El Chichón volcano (Mexico)

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