Rapa Nui (Easter Island) Rano Raraku crater lake basin: Geochemical characterization and implications for the Ahu-Moai Period

Autor: Amy Myrbo, Dario Battistel, S. Hanif, J. M. Ramirez Aliaga, Elena Argiriadis, Marco Roman, M. Bortolini, Clara Turetta, Evans Osayuki Erhenhi, Natalie Kehrwald, Aníbal Pauchard, Dave McWethy, Carlo Barbante
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Atmospheric Science
Topography
Geologic Sediments
Salinity
Rain
trace elements
Marine and Aquatic Sciences
Fresh Water
Soil
Rapa Nui
Settore CHIM/01 - Chimica Analitica
Human Activities
Magnesium
Fractionation
freshwater
Settore CHIM/12 - Chimica dell'Ambiente e dei Beni Culturali
geochemistry
Total organic carbon
Sedimentary Geology
Islands
Multidisciplinary
Geology
Anoxic waters
Chemistry
Separation Processes
crater lake
Oceanography
Archaeology
Physical Sciences
Ahu-Moai Period
Medicine
Oxidation-Reduction
Research Article
Freshwater Environments
Science
Structural basin
Environment
Research and Analysis Methods
Mining
Polynesia
Meteorology
Chlorides
Surface Water
Crater lake
particulate
Petrology
Basalt
Landforms
Nitrates
Ecology and Environmental Sciences
Chemical Compounds
Sediment
Aquatic Environments
Geomorphology
Bodies of Water
Carbon
Lakes
Settore GEO/08 - Geochimica e Vulcanologia
Period (geology)
Earth Sciences
Calcium
Hydrology
Zdroj: PLoS ONE
PLoS ONE, Vol 16, Iss 10, p e0254793 (2021)
PloS one 16 (2021): 1–23. doi:10.1371/journal.pone.0254793
info:cnr-pdr/source/autori:E. Argiriadis, M. Bortolini, N. M. Kehrwald, M. Roman, C. Turetta, S. Hanif, E. O. Erhenhi, J. M. Ramirez Aliaga, D. B. McWethy, A. E. Myrbo, A. Pauchard, C. Barbante, D. Battistel/titolo:Rapa Nui (Easter Island) Rano Raraku crater lake basin: Geochemical characterization and implications for the Ahu-Moai Period/doi:10.1371%2Fjournal.pone.0254793/rivista:PloS one/anno:2021/pagina_da:1/pagina_a:23/intervallo_pagine:1–23/volume:16
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0254793
Popis: Rano Raraku, the crater lake constrained by basaltic tuff that served as the primary quarry used to construct themoaistatues on Rapa Nui (Easter Island), has experienced fluctuations in lake level over the past centuries. As one of the only freshwater sources on the island, understanding the present and past geochemical characteristics of the lake water is critical to understand if the lake could have been a viable freshwater source for Rapa Nui. At the time of sampling in September 2017, the maximum lake depth was ~1 m. The lake level has substantially declined in the subsequent years, with the lake drying almost completely in January 2018. The lake is currently characterized by highly anoxic conditions, with a predominance of ammonium ions on nitrates, a high concentration of organic carbon in the water-sediment interface and reducing conditions of the lake, as evidenced by Mn/Fe and Cr/V ratios. Our estimates of past salinity inferred from the chloride mass balance indicates that it was unlikely that Rano Raraku provided a viable freshwater source for early Rapa Nui people. The installation of an outlet pipe around 1950 that was active until the late 1970s, as well as grazing of horses on the lake margins appear to have significantly impacted the geochemical conditions of Rano Raraku sediments and lake water in recent decades. Such impacts are distinct from natural environmental changes and highlight the need to consider the sensitivity of the lake geochemistry to human activities.
Databáze: OpenAIRE
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