EGU2020-2461
https://doi.org/10.5194/egusphere-egu2020-2461
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Numerical simulations to study the geodynamic origin of Los Humeros Volcanic Field in Mexico

Andrés David Bayona Ordóñez1 and Vlad Constantin Manea1,2
Andrés David Bayona Ordóñez and Vlad Constantin Manea
  • 1Computational Geodynamics Laboratory, Centro de Geociencias, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro, 76230, Mexico (adbayonao@geociencias.unam.mx)
  • 2Astronomical Institute of the Romanian Academy, 040557, Bucharest, Romania (vlad@geociencias.unam.mx)

Los Humeros Volcanic Field (LHVF) represents one of the key volcanic calderas in Mexico. Nowadays, LHVF is the third largest geothermal field in Mexico in terms of energy output, with an installed capacity of 94 MWe. The caldera is about 21 by 15 km wide and is located in the Serdán Oriental basin, east of the Trans- Mexican Volcanic Belt in the central-eastern part of the country, roughly 440 km away from the Middle American Trench. In this study we show results of numerical simulations of magma intrusion in order to better understand the deep origin of the caldera. For this purpose, we used high-resolution two-dimensional coupled petrological-thermomechanical numerical simulations of magma intrusion where an initial thermal anomaly was placed in the asthenosphere just below the lithospheric mantle. We performed a parametric study where we investigated the influence of several parameters such as the diameter of the thermal anomaly, the excess temperature and the regional tectonic regime. These 2D simulations were carried out using the finite difference method coupled with the cell marker technique and employing the multigrid method. The physical parameters used for the Earth’s layers (asthenosphere, lithospheric mantle, lower crust and upper crust) and for the composition of the magmatic intrusion were taken from literature and previously established models. In addition, we considered a viscoelastoplastic rheology and the simulations included erosion and surface sediment transport. Modeling results showed that only under certain conditions of temperature excess, initial diameter of the deep thermal anomalies that come in a specific chain-type sequence, it is possible to form a volcanic caldera similar with the dimensions of the LHVF. The temperature excess (ΔT = ~150K) suggested a deep origin for the thermal anomaly with an approximate depth of ~380 km, where currently the surface of the Cocos slab is located below the North American Plate. Additionally, we found that several magmatic pulses can reach the surface only if we consider in our models a small horizontal extension rate consistent with the extensional tectonic regime in the region.

How to cite: Bayona Ordóñez, A. D. and Manea, V. C.: Numerical simulations to study the geodynamic origin of Los Humeros Volcanic Field in Mexico, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2461, https://doi.org/10.5194/egusphere-egu2020-2461, 2020

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Presentation version 1 – uploaded on 02 May 2020
  • CC1: Questions and answers from the live chat during EGU2020, Michael Heap, 11 May 2020

    Q: Are the different layers in your numerical model described by different material properties?

    A: Each layer has its own physical properties (density, thermal expansion, etc.)

    Q: Hello, would you consider the alternative of a mantle mega porosity wave as the origin of your pulses?

    A: The main hypothesis is that its formation could be associated with partial melting in areas where the slab is not as deep. Later, the melt migrated horizontally under the crust until it reached conduits through which it could ascend. This has been documented in seismological studies. Its geodynamic origin is highly debated, as the caldera is 440 km from the trench, and the slab of the Cocos plate is approximately 380 km deep below Los Humeros.

    Q: Do your simulations provide constrain on the total amount of time required to build this caldera?

    A: It is one of the limitations that we have, since the Miocene there is extension in the region, which is believed to have facilitated the formation of the caldera, but in the models we use a slightly larger expansion rate to accelerate the simulations.