Alteration‐Induced Volcano Instability at La Soufrière de Guadeloupe (Eastern Caribbean)

Abstract

Volcanoes are inherently unstable structures that are built haphazardly, in both space and time, from the products of successive effusive and explosive eruptions and endogenous growth. These materials have highly variable physical and mechanical properties (Heap & Violay, 2021) and often form oversteepened and unstable slopes. As a result, volcano deformation (such as volcano spreading; Borgia et al., 2000) and mass wasting events (such as debris avalanches resulting from partial flank collapse, lahars, and rockfalls;

Monitoring Hydrothermal Activity Using Major and Trace Elements in Low-Temperature Fumarolic Condensates: The Case of La Soufriere de Guadeloupe Volcano

“…Water-rock interaction processes were also deduced following the behavior of halogens, which presented similar relative concentrations in host rocks [60] and condensates (i.e., higher concentrations of Cl and I compared to Br), suggesting incipient isochemical dissolution. This behavior was expected at La Soufriere volcano, where water-rock exchanges producing extensive hydrothermal alteration have already been recognized [11,42,53,55,64,66,67].…”

Catchment‐Scale Architecture of the Deep Critical Zone Revealed by Seismic Imaging

“…For instance, we were only able to find a single publication reporting elastic parameters for iron oxides and hydroxides (Chicot et al., 2011). In future works, we suggest to collect regolith samples at multiple locations along the seismic lines to estimate the bulk elastic parameters of the dry frame along with porosity and water content (Heap et al., 2021), so as to further constrain the petrophysical model.…”

Gas Monitoring of Volcanic-Hydrothermal Plumes in a Tropical Environment: The Case of La Soufrière de Guadeloupe Unrest Volcano (Lesser Antilles)

“…This is one main mechanism (together with pyrite wet oxidation) that produces so-called acid-sulfate waters, which like at La Soufrière react quickly with host rocks to give advanced argillic alteration parageneses (Heap et al, 2021) dominated by kaolinite and alunite, as well as gypsum, opal, and hydrated iron oxides (Steiner, 1977). H 2 S partial pressure, hence concentration, in such hydrothermal environments is then buffered by such parageneses via coexisting pyrite, an unspecified Fe-Al-silicate [indicated as (FeO), such as chlorite or epidote and the corresponding Al-silicate in its protonated, Fe-free form, (H 2 O) via (Giggenbach, 1980;Giggenbach, 1987):…”

“…Sealing by precipitation, in the host-rock voids, of silica dissolved in hydrothermal fluids can also lead to reduced permeabilities in different regions of the hydrothermal system (e.g., Komorowski et al, 1997Komorowski et al, , 2010Boudon et al, 1998). Opal (i.e., hydrothermal silica) was identified in the non-juvenile fragments of the ash produced by explosions during the 1976-1977 eruption of La Soufrière (Feuillard et al, 1983;Salaün et al, 2011;Heap et al, 2021;Inostroza et al, subjudice). Hence, continuous degassing at depth, verified by a high total dry gas flux at the surface (Figure 4), progressively leads to impermeable sealing at the hydrothermal system-host-rock interface, only allowing concentrated gas escape through preferential drains.…”