Rare Earth Elements Variations in a Hyperacid Crater Lake and Their Relations With Changes in Phreatic Activity, Physico-Chemical Parameters, and Chemical Composition: The Case of Poas Volcano (Costa Rica)
Por:
Pappaterra, Sabrina, Inguaggiato, Claudio, Rouwet, Dmitri, Mora-Amador, Raul, Ramirez-Umana, Carlos, Gonzalez, Gino, Brusca, Lorenzo, Peiffer, Loic, Levresse, Gilles, Bellomo, Sergio
Publicada:
3 ene 2022
Categoría:
Earth and planetary sciences (miscellaneous)
Resumen:
Decades of geochemical monitoring at active crater lakes worldwide have
confirmed that variations in major elements and physico-chemical
parameters are useful to detect changes in volcanic activity. However,
it is still arduous to identify precursors of single phreatic eruptions.
During the unrest phase of 2009-2016, at least 679 phreatic eruptions
occurred at the hyperacid and hypersaline crater lake Laguna Caliente of
Poas volcano (Costa Rica). In this study, we investigate the temporal
variations of Rare Earth Elements (REE) dissolved in Laguna Caliente in
order to 1) scrutinize if they can be used as a new geochemical tool to
monitor changes of phreatic activity at hyperacid crater lakes and 2)
identify the geochemical processes responsible for the variations of REE
concentrations in the lake. The total concentration of REE varies from
950 to 2,773 mu g kg(-1). (La/Pr)(N-local rock) ratios range from 0.93
to 1.35, and Light REE over Heavy REE (LREE/HREE)(N-local rock) ratios
vary from 0.71 to 0.95. These same parameters vary in relation to
significant changes in phreatic activity; in particular, the
(La/Pr)(N-local rock) ratio increases as phreatic activity increases,
while that of (LREE/HREE)(N-local rock) decreases when phreatic activity
increases. REE concentrations and their ratios were compared with the
variations of major elements and physico-chemical parameters of the
lake. Calcium versus (La/Pr)(N-local rock) and versus
(LREE/HREE)(N-local rock) ratios show different trends compared to the
other major elements (Na, K, Mg, Al, Fe, SO4, and Cl). Moreover, a
higher loss of Ca (up to 2,835 ppm) in lake water was found with respect
to the loss of Al, K, and Na. This loss of Ca is argued to be due to
gypsum precipitation, a process corroborated by the mass balance
calculation simulating the precipitation of gypsum and the
contemporaneous removal of REE from the lake water. The observed
relations between REE, changes in phreatic activity, and the parameters
commonly used for the monitoring of hyperacid volcanic lakes encourage
investigating more on the temporal and cause-effect relationship between
REE dynamics and changes in phreatic activity at crater lake-bearing
volcanoes.
Filiaciones:
Pappaterra, Sabrina:
Ctr Invest Cient & Educ Super Ensenada, Posgrad Ciencias Tierra, Baja Calif CICESE, Ensenada, Mexico
Inguaggiato, Claudio:
Ctr Invest Cient & Educ Super Ensenada, Dept Geol, Baja Calif CICESE, Ensenada, Mexico
Ist Nazl Geofis & Vulcanol, Sez Bologna, Bologna, Italy
Rouwet, Dmitri:
Ist Nazl Geofis & Vulcanol, Sez Bologna, Bologna, Italy
Mora-Amador, Raul:
Volcanes Sin Fronteras, San Jose, Costa Rica
Ramirez-Umana, Carlos:
Serv Geol Ambiental Costa Rica SeGeoAm, San Jose, Costa Rica
Gonzalez, Gino:
Ist Nazl Geofis & Vulcanol, Sez Bologna, Bologna, Italy
Volcanes Sin Fronteras, San Jose, Costa Rica
Univ Bari Aldo Moro, Dipt Sci Terra & Geoambientali, Bari, Italy
Brusca, Lorenzo:
Ist Nazl Geofis & Vulcanol, Sez Palermo, Palermo, Italy
Peiffer, Loic:
Ctr Invest Cient & Educ Super Ensenada, Dept Geol, Baja Calif CICESE, Ensenada, Mexico
Levresse, Gilles:
UNAM, Ctr Geociencias, Queretaro, Mexico
Bellomo, Sergio:
Ist Nazl Geofis & Vulcanol, Sez Palermo, Palermo, Italy
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