Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years
A combination of carbon-to-nitrogen ratios (TOC/TN), Rock Eval-analyses, and stable isotope values of bulk nitrogen (δ15N) and organic carbon (δ13Corg) was used to characterize bulk organic matter (OM) of a piston core from the Patagonian maar lake Laguna Potrok Aike (Argentina) for the purpose of p...
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2009
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09212728_v42_n1_p81_Mayr http://hdl.handle.net/20.500.12110/paper_09212728_v42_n1_p81_Mayr |
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paper:paper_09212728_v42_n1_p81_Mayr2023-06-08T15:50:18Z Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years Isotope mixing model Lake sediments Late Quaternary Organic matter Rock Eval analyses Soil erosion South America Stable isotopes carbon isotope catchment chemical composition diatom environmental change fossil record geochronology Holocene isotopic analysis lacustrine deposit macrophyte microfossil organic carbon paleoenvironment soil erosion soil organic matter stable isotope Argentina Laguna Potrok Aike Santa Cruz [Argentina] South America Bacillariophyta Cyanobacteria A combination of carbon-to-nitrogen ratios (TOC/TN), Rock Eval-analyses, and stable isotope values of bulk nitrogen (δ15N) and organic carbon (δ13Corg) was used to characterize bulk organic matter (OM) of a piston core from the Patagonian maar lake Laguna Potrok Aike (Argentina) for the purpose of palaeoenvironmental reconstruction. Sedimentary data were compared with geochemical signatures of potential OM sources from Laguna Potrok Aike and its catchment area to identify the sources of sedimentary OM. Correlation patterns between isotopic data and TOC/TN ratios allowed differentiation of five distinct phases with different OM composition. Before 8470 calibrated 14C years before present (cal. yrs BP) and after 7400 cal. yrs BP, isotopic and organo-geochemical fingerprints indicate that the sediments of Laguna Potrok Aike consist predominantly of soil and diatom OM with varying admixtures of cyanobacterial and aquatic macrophyte OM. For a short phase of the early Holocene (ca. 8470-7400 cal. yrs BP), however, extremely high input of soil OM is implied by isotopic fingerprints. Previous seismic and geochronological results indicate a severe lake-level drop of 33 m below present-day shortly before 6590 cal. yrs BP. It is suggested that this lake level drop was accompanied by increased erosion of shore banks and channel incision enhancing soil OM deposition in the lake basin. Thus, isotopic data can be linked to hydrological variations at Laguna Potrok Aike and allow a more precise dating of this extremely low lake level. An isotopic mixing model was used including four different sources (soil, cyanobacteria, diatom and aquatic macrophyte OM) to model OM variations and the model results were compared with quantitative microfossil data. © 2008 Springer Science+Business Media B.V. 2009 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09212728_v42_n1_p81_Mayr http://hdl.handle.net/20.500.12110/paper_09212728_v42_n1_p81_Mayr |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Isotope mixing model Lake sediments Late Quaternary Organic matter Rock Eval analyses Soil erosion South America Stable isotopes carbon isotope catchment chemical composition diatom environmental change fossil record geochronology Holocene isotopic analysis lacustrine deposit macrophyte microfossil organic carbon paleoenvironment soil erosion soil organic matter stable isotope Argentina Laguna Potrok Aike Santa Cruz [Argentina] South America Bacillariophyta Cyanobacteria |
| spellingShingle |
Isotope mixing model Lake sediments Late Quaternary Organic matter Rock Eval analyses Soil erosion South America Stable isotopes carbon isotope catchment chemical composition diatom environmental change fossil record geochronology Holocene isotopic analysis lacustrine deposit macrophyte microfossil organic carbon paleoenvironment soil erosion soil organic matter stable isotope Argentina Laguna Potrok Aike Santa Cruz [Argentina] South America Bacillariophyta Cyanobacteria Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years |
| topic_facet |
Isotope mixing model Lake sediments Late Quaternary Organic matter Rock Eval analyses Soil erosion South America Stable isotopes carbon isotope catchment chemical composition diatom environmental change fossil record geochronology Holocene isotopic analysis lacustrine deposit macrophyte microfossil organic carbon paleoenvironment soil erosion soil organic matter stable isotope Argentina Laguna Potrok Aike Santa Cruz [Argentina] South America Bacillariophyta Cyanobacteria |
| description |
A combination of carbon-to-nitrogen ratios (TOC/TN), Rock Eval-analyses, and stable isotope values of bulk nitrogen (δ15N) and organic carbon (δ13Corg) was used to characterize bulk organic matter (OM) of a piston core from the Patagonian maar lake Laguna Potrok Aike (Argentina) for the purpose of palaeoenvironmental reconstruction. Sedimentary data were compared with geochemical signatures of potential OM sources from Laguna Potrok Aike and its catchment area to identify the sources of sedimentary OM. Correlation patterns between isotopic data and TOC/TN ratios allowed differentiation of five distinct phases with different OM composition. Before 8470 calibrated 14C years before present (cal. yrs BP) and after 7400 cal. yrs BP, isotopic and organo-geochemical fingerprints indicate that the sediments of Laguna Potrok Aike consist predominantly of soil and diatom OM with varying admixtures of cyanobacterial and aquatic macrophyte OM. For a short phase of the early Holocene (ca. 8470-7400 cal. yrs BP), however, extremely high input of soil OM is implied by isotopic fingerprints. Previous seismic and geochronological results indicate a severe lake-level drop of 33 m below present-day shortly before 6590 cal. yrs BP. It is suggested that this lake level drop was accompanied by increased erosion of shore banks and channel incision enhancing soil OM deposition in the lake basin. Thus, isotopic data can be linked to hydrological variations at Laguna Potrok Aike and allow a more precise dating of this extremely low lake level. An isotopic mixing model was used including four different sources (soil, cyanobacteria, diatom and aquatic macrophyte OM) to model OM variations and the model results were compared with quantitative microfossil data. © 2008 Springer Science+Business Media B.V. |
| title |
Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years |
| title_short |
Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years |
| title_full |
Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years |
| title_fullStr |
Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years |
| title_full_unstemmed |
Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years |
| title_sort |
isotopic fingerprints on lacustrine organic matter from laguna potrok aike (southern patagonia, argentina) reflect environmental changes during the last 16,000 years |
| publishDate |
2009 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09212728_v42_n1_p81_Mayr http://hdl.handle.net/20.500.12110/paper_09212728_v42_n1_p81_Mayr |
| _version_ |
1768542557851090944 |