Publikationsdatum:
2024-03-20
Beschreibung:
Volcanic lakes are complex natural systems and their chemical composition is
related to a myriad of processes. The chemical composition of major, minor, Rare
Earth Elements (REE) and physico-chemical parameters at the hyperacid crater
lake of Rincón de la Vieja volcano (Costa Rica) are here investigated during
February 2013–August 2014. The study of the lake chemical composition
allows to identify the main geochemical processes occurring in the lake and to
track the changes in the volcanic activity, both important for active volcanoes
monitoring. The total REE concentration ( REE) dissolved in the crater lake varies
from 2.7 to 3.6 mg kg−1 during the period of observation. REE in the water lake
samples normalized to the average volcanic local rock (REEN-local rock) are
depleted in light REE (LREE). On the contrary REEN-local rock in the solids
precipitated (mainly gypsum/anhydrite), from lake water samples in laboratory
at 22°C, are enriched in LREE. The low variability of (La/Pr)N-local rock and (LREE/
HREE)N-local rock ratios (0.92–1.07 and 0.66–0.81, respectively) in crater lake
waters is consistent with the low phreatic activity (less than 10 phreatic
eruptions in 2 years) observed during the period of observation. This period of
low activity precedes the unrest started in 2015, thus, it could be considered as a
pre-unrest, characterized by infrequent phreatic eruptions. No clear changes in
the REE chemistry are associated with the phreatic eruption occurred at mid-
2013. The results obtained investigating water-rock interaction processes at theRincón de la Vieja crater lake show that rock dissolution and mineral precipitation/
dissolution are the main processes that control the variability of cations
composition over time. In particular, precipitation and dissolution of gypsum
and alunite are responsible for the variations of REE in the waters. Despite the
low variations of (La/Pr)N-local rock and (LREE/HREE)N-local rock ratios, this study
allows to suggest that REE can be used, together with major elements, as
practical tracers of water-rock interaction processes and mineral precipitation/
dissolution at active hyperacid crater lakes over time, also during periods of
quiescence and low phreatic activity.
Beschreibung:
Published
Beschreibung:
1197568
Beschreibung:
OSV3: Sviluppo di nuovi sistemi osservazionali e di analisi ad alta sensibilità
Beschreibung:
JCR Journal
Schlagwort(e):
Rare earth elements
;
hyperacid crater lake
;
geochemical monitoring
;
sulfate minerals
;
water-rock interaction
Repository-Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Materialart:
article
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