0000000000341103
AUTHOR
B. J. P. Kaus
Control of 3-D tectonic inheritance on fold-and-thrust belts: insights from 3-D numerical models and application to the Helvetic nappe system
We apply three-dimensional (3-D) thermo-mechanical numerical simulations of the shortening of the upper crustal region of a passive margin in order to investigate the control of 3-D laterally variable inherited structures on fold-and-thrust belt evolution and associated nappe formation. We consider tectonic inheritance by employing an initial model configuration with basement horst and graben structures having laterally variable geometry and with sedimentary layers having different mechanical strength. We use a visco-plastic rheology with a temperature-dependent flow law and a Drucker–Prager yield criterion. The models show the folding, detachment (shearing off) and horizontal transport of …
A Multiphysics Approach to Constrain the Dynamics of the Altiplano‐Puna Magmatic System
Continuous Interferometric Synthetic Aperture Radar (InSAR) monitoring (> 25 years) has revealed a concentric surface deformation pattern above the Altiplano-Puna magma body (APMB) in the central Andes. Here, we use a joint interpretation of seismic imaging, gravity anomalies and InSAR data to constrain location, 3D geometry and density of the magma body. By combining gravity modelling, thermomechanical modelling, scaling law analysis and Bayesian inference, we are able to create a relationship between the geometry of a mid-crustal magma body and surface observations. Furthermore, we can estimate the uncertainties associated with the geometry of the APMB and identify the most important para…
Investigating the effects of intersection flow localization in equivalent-continuum-based upscaling of flow in discrete fracture networks
Abstract. Predicting effective permeabilities of fractured rock masses is a crucial component of reservoir modeling. Its often realized with the discrete fracture network (DFN) method, whereby single-phase incompressible fluid flow is modeled in discrete representations of individual fractures in a network. Depending on the overall number of fractures, this can result in high computational costs. Equivalent continuum models (ECMs) provide an alternative approach by subdividing the fracture network into a grid of continuous medium cells, over which hydraulic properties are averaged for fluid flow simulations. While continuum methods have the advantage of lower computational costs and the pos…
Decompression and Fracturing Caused by Magmatically Induced Thermal Stresses
Studies of host rock deformation around magmatic intrusions usually focus on the development of stresses directly related to the intrusion process. This is done either by considering an inflating region that represents the intruding body, or by considering multiphase deformation. Thermal processes, especially volume changes caused by thermal expansion are typically ignored. We show that thermal stresses around upper crustal magma bodies are likely to be significant and sufficient to create an extensive fracture network around the magma body by brittle yielding. At the same time, cooling induces decompression within the intrusion, which can promote the appearance of a volatile phase. Volatil…
Quantification of volcano deformation caused by volatile accumulation and release
<p>Magma stored in the crust may exsolve a significant amount of volatiles, primarily CO<sub>2</sub>, but also H<sub>2</sub>O and SO<sub>2</sub> if cooling promotes crystallisation and volatile exsolution. These volatiles may, over time, segregate and accumulate into a gas-rich foam at the roof of the magma body. This is the underpinning process to explain the frequently observed ‘excess gas’ produced in explosive eruptions, where the amount of erupted SO<sub>2</sub> is much larger than can be explained by the mass of erupted products and …
MAGEMin, an Efficient Gibbs Energy Minimizer: Application to Igneous Systems
Prediction of stable mineral equilibria in the Earth's lithosphere is critical to unravel the tectonomagmatic history of exposed geological sections. While the recent advances in geodynamic modeling allow us to explore the dynamics of magmatic transfer in solid mediums, there is to date no available thermodynamic package that can easily be linked and efficiently be accounted for the computation of phase equilibrium in magmatic systems. Moreover, none of the existing tools fully exploit single point calculation parallelization, which strongly hinders their applicability for direct geodynamic coupling or for thermodynamic database inversions. Here, we present a new Mineral Assemblage Gibbs En…