Contrasting sources and conditions of shallow magmatic reservoirs of the Fui Group small eruptive centres associated with the Liquiñe-Ofqui Fault Zone (Chilean Andes)

Simple item page
dc.coverageDOI: 10.1016/j.jsames.2022.103875
dc.creatorMallea-Lillo, Francisca
dc.creatorParada, Miguel A.
dc.creatorMorgado, Eduardo
dc.creatorContreras, Claudio
dc.creatorHübner, Darío
dc.date2022
dc.date.accessioned05-01-2026 18:18
dc.date.available05-01-2026 18:18
dc.description<p>Along the Southern Volcanic Zone of the Andes, the Liquiñe Ofqui Fault Zone controls the occurrence and distribution of small eruptive centres and stratovolcanoes. The Fui Group are clusters of Holocene small eruptive centres within the vicinity of ?5.5 km west of the Liquiñe Ofqui Fault Zone and 8–16 km ENE from the Mocho-Choshuenco Volcanic Complex. Although separated ?2 km from each other, the Fui Norte (north) volcanic products are olivine-rich basalts (49–52 wt% SiO<sub>2</sub>) and enriched in incompatible elements, whilst the Fui Sur (south) materials are basaltic andesites to andesites (55–58 wt% SiO<sub>2</sub>) with less amount of olivine but more plagioclase and clinopyroxene and depleted in incompatible elements. Crystal clots of olivine, plagioclase and clinopyroxene are abundant in all the studied samples. We found two compositional zones of olivine and plagioclase: High-Fo, High-An (Zone 1, Fo<sub>78-89</sub> and An<sub>76-93</sub>) and Low-Fo, Low-An (Zone 2, Fo<sub>60-78</sub> and An<sub>57-73</sub>); only Zone 2 are in equilibrium with the groundmass (representing the melt) compositions. We determined shallow magmatic reservoir conditions (2–8 km and 6–19 km in the Fui Norte and Fui Sur eruptive centres, respectively) for Zone 2 crystallisation using geothermobarometers and thermodynamic modelling by rhyolite-MELTS v.1.0.2 freeware. Additionally, we determined water content dissolved in melt of 1–2.5 wt% and 2–3.8 wt% for Zone 2 compositions of the Fui Norte and Fui Sur small eruptive centres, respectively, and oxidation conditions for Zone 2 of QFM, QFM-1 and NNO. The relatively more primitive compositions of Zone 1 and the common occurrence of crystal clots with compositions of Zone 1 crystals, suggest an earlier stage of crystallisation in a mushy zone of the shallow reservoirs. Although their geographical proximity, we propose that the magmatic origins of Fui Norte and Fui Sur small eruptive centres are independent due to their differing petrographic and geochemical features and the likely genetic relation of Fui Sur magmas with those erupted from Mocho-Choshuenco Volcanic Complex, where the structures associated to the Liquiñe Ofqui Fault Zone aids the magmatic ascent and emplacement of the volcanic products.</p>eng
dc.identifierhttps://investigadores.uandes.cl/en/publications/64d58756-8b2f-4236-9438-a837fbd68c61
dc.languageeng
dc.rightsinfo:eu-repo/semantics/restrictedAccess
dc.sourcevol.117 (2022)
dc.subjectFui group
dc.subjectPre-eruptive conditions
dc.subjectShallow reservoir
dc.subjectSmall eruptive centres
dc.subjectSouthern volcanic zone of the andes
dc.subjectSDG 3 - Good Health and Well-being
dc.titleContrasting sources and conditions of shallow magmatic reservoirs of the Fui Group small eruptive centres associated with the Liquiñe-Ofqui Fault Zone (Chilean Andes)eng
dc.typeArticleeng
dc.typeArtículospa
Files
Collections
Pure-CRIS