Experimental weathering rates of aluminium-silicates
type: Dataset
description: The chemical weathering of primary rocks and minerals in natural systems has a major impact on soil development and its composition. Chemical weathering is driven to a large extent by mineral dissolution. Through mineral dissolution, elements are released into groundwater and can readily react to precipitate secondary minerals such as clays, zeolites, and carbonates. Carbonates form from divalent cations (e.g. Ca, Fe and Mg) and CO2, and kaolin clay and gibbsite formation is attributed to the weathering of aluminium-rich minerals, most notably the feldspars. The CarbFix Project in Hellisheiði SW-Iceland aims to use natural weathering processes to form carbonate minerals by the re-injection of CO2 from a geothermal power plant back into surrounding basaltic rocks. This process is driven by the dissolution of basaltic rocks, rich in divalent cations, which can combine with injected CO2 to form and precipitate carbonates. This thesis focuses on the dissolution behaviour of Stapafell crystalline basalt, which consists of three major phases (plagioclase, pyroxene, and olivine) and is rich in divalent cations. Steady-state element release rates from crystalline basalt at far-from-equilibrium conditions were measured at pH from 2 to 11 and temperatures from 5° to 75° C in mixed-flow reactors. Steady-state Si and Ca release rates exhibit a U-shaped variation with pH, where rates decrease with increasing pH at acid condition but increase with increasing pH at alkaline conditions. Silicon release rates from crystalline basalt are comparable to Si release rates from basaltic glass of the same chemical composition at low pH and temperatures ≥25°C but slower at alkaline pH and temperatures ≥50°C. In contrast, Mg and Fe release rates decrease continuously with increasing pH at all temperatures. This behaviour is interpreted to stem from the contrasting dissolution behaviours of the three major minerals comprising the basalt: plagioclase, pyroxene, and olivine. Element release rat…
issued: 2026-05-07T08:27:18.588759
language: en
modified: 2026-05-07T08:27:18.588764
contact point: Organization
  fn: CCSD
keyword: aluminium-silicate-weathering
keyword: carbfix
keyword: co2-sequestration
keyword: crystalline-basalt-dissolution
keyword: dissolution-basalte-crystalline
keyword: dissolution-plagioclase
keyword: gibbsite-precipitation
keyword: infoeu-reposemanticsdoctoralthesis
keyword: kaolinite-precipitation
keyword: plagioclase-dissolution
keyword: precipitation-gibbsite
keyword: precipitation-kaolinite
keyword: precipitation-of-secondary-aluminium-minerals
keyword: sdemcgenvironmental-sciencesglobal-changes
keyword: sdustugcsciences-of-the-universe-physicsearth-sciencesgeochemistry
keyword: sequestration-co2
keyword: theses
landing page: https://theses.hal.science/tel-00933440

Experimental weathering rates of aluminium-silicates
type: Distribution
format: HTML
issued: 2026-05-07T08:27:18.601492
modified: 2026-05-07T08:27:18.561062
access URL: https://theses.hal.science/tel-00933440

test_moissonnage_selune
type: Agent