Spatial variations of Sr–Nd isotopic ratios, mineralogical and elemental compositions of cryoconite in an Alaskan glacier
ABSTRACT To understand the geological origins of minerals in cryoconite and the nutrients sources for microbes on glaciers, we analyzed the Sr–Nd isotopic ratios of the four mineral fractions in cryoconites including saline, carbonate, phosphate, silicate and the organic fraction obtained from Gulka...
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crcambridgeupr:10.1017/aog.2019.2 2024-06-09T07:38:30+00:00 Spatial variations of Sr–Nd isotopic ratios, mineralogical and elemental compositions of cryoconite in an Alaskan glacier Nagatsuka, Naoko Takeuchi, Nozomu Shin, Ki-Cheol Nakano, Takanori 2018 http://dx.doi.org/10.1017/aog.2019.2 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305519000028 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Annals of Glaciology volume 59, issue 77, page 147-158 ISSN 0260-3055 1727-5644 journal-article 2018 crcambridgeupr https://doi.org/10.1017/aog.2019.2 2024-05-15T13:07:26Z ABSTRACT To understand the geological origins of minerals in cryoconite and the nutrients sources for microbes on glaciers, we analyzed the Sr–Nd isotopic ratios of the four mineral fractions in cryoconites including saline, carbonate, phosphate, silicate and the organic fraction obtained from Gulkana Glacier in Alaska. The isotopes in the silicate mineral fraction exhibited spatial variation within the glacier ( 87 Sr/ 86 Sr: 0.704533–0.709563, ε Nd (0): −16.0 to 0.5), which can be explained by the different mixing ratios of the two distinct sources: one of the sources is lateral and terminal moraines or soil, and the other is the medial moraine of the glacier. The minerals in the cryoconite at the lower sites in the glacier are likely derived from the former source, whereas those at the upper sites are from latter sources. The mineralogical and elemental compositions also support mixing of the silicate minerals from the two local sources. The Sr isotopic ratios of the organic fraction also showed spatial variation on the glacier in the middle sites – a trend similar to those of the phosphate fraction. The results suggest that the organic matter is mostly the byproducts of microbes using the phosphate minerals as a nutrient source. Article in Journal/Newspaper Annals of Glaciology glacier glaciers Alaska Cambridge University Press Annals of Glaciology 59 77 147 158 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
ABSTRACT To understand the geological origins of minerals in cryoconite and the nutrients sources for microbes on glaciers, we analyzed the Sr–Nd isotopic ratios of the four mineral fractions in cryoconites including saline, carbonate, phosphate, silicate and the organic fraction obtained from Gulkana Glacier in Alaska. The isotopes in the silicate mineral fraction exhibited spatial variation within the glacier ( 87 Sr/ 86 Sr: 0.704533–0.709563, ε Nd (0): −16.0 to 0.5), which can be explained by the different mixing ratios of the two distinct sources: one of the sources is lateral and terminal moraines or soil, and the other is the medial moraine of the glacier. The minerals in the cryoconite at the lower sites in the glacier are likely derived from the former source, whereas those at the upper sites are from latter sources. The mineralogical and elemental compositions also support mixing of the silicate minerals from the two local sources. The Sr isotopic ratios of the organic fraction also showed spatial variation on the glacier in the middle sites – a trend similar to those of the phosphate fraction. The results suggest that the organic matter is mostly the byproducts of microbes using the phosphate minerals as a nutrient source. |
format |
Article in Journal/Newspaper |
author |
Nagatsuka, Naoko Takeuchi, Nozomu Shin, Ki-Cheol Nakano, Takanori |
spellingShingle |
Nagatsuka, Naoko Takeuchi, Nozomu Shin, Ki-Cheol Nakano, Takanori Spatial variations of Sr–Nd isotopic ratios, mineralogical and elemental compositions of cryoconite in an Alaskan glacier |
author_facet |
Nagatsuka, Naoko Takeuchi, Nozomu Shin, Ki-Cheol Nakano, Takanori |
author_sort |
Nagatsuka, Naoko |
title |
Spatial variations of Sr–Nd isotopic ratios, mineralogical and elemental compositions of cryoconite in an Alaskan glacier |
title_short |
Spatial variations of Sr–Nd isotopic ratios, mineralogical and elemental compositions of cryoconite in an Alaskan glacier |
title_full |
Spatial variations of Sr–Nd isotopic ratios, mineralogical and elemental compositions of cryoconite in an Alaskan glacier |
title_fullStr |
Spatial variations of Sr–Nd isotopic ratios, mineralogical and elemental compositions of cryoconite in an Alaskan glacier |
title_full_unstemmed |
Spatial variations of Sr–Nd isotopic ratios, mineralogical and elemental compositions of cryoconite in an Alaskan glacier |
title_sort |
spatial variations of sr–nd isotopic ratios, mineralogical and elemental compositions of cryoconite in an alaskan glacier |
publisher |
Cambridge University Press (CUP) |
publishDate |
2018 |
url |
http://dx.doi.org/10.1017/aog.2019.2 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305519000028 |
genre |
Annals of Glaciology glacier glaciers Alaska |
genre_facet |
Annals of Glaciology glacier glaciers Alaska |
op_source |
Annals of Glaciology volume 59, issue 77, page 147-158 ISSN 0260-3055 1727-5644 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/aog.2019.2 |
container_title |
Annals of Glaciology |
container_volume |
59 |
container_issue |
77 |
container_start_page |
147 |
op_container_end_page |
158 |
_version_ |
1801373242556940288 |