Effects of seafloor and laboratory dissolution on the Mg/Ca composition of Globigerinoides sacculifer and Orbulina universa tests - A laser ablation ICPMS microanalysis perspective
Partial or selective dissolution of planktonic foraminiferal tests on the seafloor has been shown to alter original test Mg/Ca compositions and thus may limit the accuracy of Mg/Ca-based thermometry for reconstructions of past sea surface temperatures. We have employed laser ablation ICPMS to determ...
Published in: | Earth and Planetary Science Letters |
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Online Access: | http://hdl.handle.net/1885/32722 https://doi.org/10.1016/j.epsl.2010.01.039 https://openresearch-repository.anu.edu.au/bitstream/1885/32722/5/SadekovEggins_Effects_2010.pdf.jpg https://openresearch-repository.anu.edu.au/bitstream/1885/32722/7/01_Sadekov_Effects_of_seafloor_and_2010.pdf.jpg |
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ftanucanberra:oai:openresearch-repository.anu.edu.au:1885/32722 2024-01-14T10:10:03+01:00 Effects of seafloor and laboratory dissolution on the Mg/Ca composition of Globigerinoides sacculifer and Orbulina universa tests - A laser ablation ICPMS microanalysis perspective Sadekov, Aleksey Eggins, Stephen Klinkhammer, G Rosenthal, Y http://hdl.handle.net/1885/32722 https://doi.org/10.1016/j.epsl.2010.01.039 https://openresearch-repository.anu.edu.au/bitstream/1885/32722/5/SadekovEggins_Effects_2010.pdf.jpg https://openresearch-repository.anu.edu.au/bitstream/1885/32722/7/01_Sadekov_Effects_of_seafloor_and_2010.pdf.jpg unknown Elsevier 0012-821X http://hdl.handle.net/1885/32722 doi:10.1016/j.epsl.2010.01.039 https://openresearch-repository.anu.edu.au/bitstream/1885/32722/5/SadekovEggins_Effects_2010.pdf.jpg https://openresearch-repository.anu.edu.au/bitstream/1885/32722/7/01_Sadekov_Effects_of_seafloor_and_2010.pdf.jpg Earth and Planetary Science Letters Keywords: Calcite crusts Calcite dissolution Chamber walls Core-top samples Diagenetics Indian ocean Laser-ablation-ICP-MS Mean values Outer surface Paleoceanography Planktonic foraminifera Sea floor Sea surface temperatures Selective dissolution Sele Calcite dissolution Calcite lysocline Laser ablation ICPMS Mg/Ca thermometry Journal article ftanucanberra https://doi.org/10.1016/j.epsl.2010.01.039 2023-12-15T09:37:55Z Partial or selective dissolution of planktonic foraminiferal tests on the seafloor has been shown to alter original test Mg/Ca compositions and thus may limit the accuracy of Mg/Ca-based thermometry for reconstructions of past sea surface temperatures. We have employed laser ablation ICPMS to determine the extent of dissolution-caused changes in Mg/Ca distribution across individual chamber walls of the planktonic foraminifera Globigerinoides sacculifer and Orbulina universa. G. sacculifer samples collected from a core-top depth transect in the NE Indian Ocean and laboratory dissolution experiments show little if any evidence of preferential removal of Mg-rich calcite layers by progressive dissolution of the tests. We attribute the absence of selective dissolution to the banded distribution of Mg across the chamber walls of these foraminiferal species and to the minimal presence of calcite crusts with relatively low-Mg composition on the outer surfaces of tests. Mg/Ca microanalyses of G. sacculifer from core-top samples further indicate that for samples collected above the calcite lysocline the effect of postdepositional dissolution on Mg/Ca sample mean values is minimal and within the uncertainty of Mg/Ca thermometry (i.e. ±0.4mmol/mol; ±0.8°C at ~28°C). Comparison with previously published results for G. sacculifer supports these observations. Simple modelling of G. sacculifer test dissolution indicates that selective removal of calcite with high-Mg/Ca values from within the final chamber of G. sacculifer test appears insufficient to cause the ~10% decrease in Mg/Ca values observed above calcite lysocline. These changes in test composition might be related to development/removal as a function of Δ[CO32-] of a thin diagenetic surface coating which has a relatively high-Mg/Ca composition (i.e. 20-25mmol/mol). Article in Journal/Newspaper Planktonic foraminifera Australian National University: ANU Digital Collections Indian Earth and Planetary Science Letters 292 3-4 312 324 |
institution |
Open Polar |
collection |
Australian National University: ANU Digital Collections |
op_collection_id |
ftanucanberra |
language |
unknown |
topic |
Keywords: Calcite crusts Calcite dissolution Chamber walls Core-top samples Diagenetics Indian ocean Laser-ablation-ICP-MS Mean values Outer surface Paleoceanography Planktonic foraminifera Sea floor Sea surface temperatures Selective dissolution Sele Calcite dissolution Calcite lysocline Laser ablation ICPMS Mg/Ca thermometry |
spellingShingle |
Keywords: Calcite crusts Calcite dissolution Chamber walls Core-top samples Diagenetics Indian ocean Laser-ablation-ICP-MS Mean values Outer surface Paleoceanography Planktonic foraminifera Sea floor Sea surface temperatures Selective dissolution Sele Calcite dissolution Calcite lysocline Laser ablation ICPMS Mg/Ca thermometry Sadekov, Aleksey Eggins, Stephen Klinkhammer, G Rosenthal, Y Effects of seafloor and laboratory dissolution on the Mg/Ca composition of Globigerinoides sacculifer and Orbulina universa tests - A laser ablation ICPMS microanalysis perspective |
topic_facet |
Keywords: Calcite crusts Calcite dissolution Chamber walls Core-top samples Diagenetics Indian ocean Laser-ablation-ICP-MS Mean values Outer surface Paleoceanography Planktonic foraminifera Sea floor Sea surface temperatures Selective dissolution Sele Calcite dissolution Calcite lysocline Laser ablation ICPMS Mg/Ca thermometry |
description |
Partial or selective dissolution of planktonic foraminiferal tests on the seafloor has been shown to alter original test Mg/Ca compositions and thus may limit the accuracy of Mg/Ca-based thermometry for reconstructions of past sea surface temperatures. We have employed laser ablation ICPMS to determine the extent of dissolution-caused changes in Mg/Ca distribution across individual chamber walls of the planktonic foraminifera Globigerinoides sacculifer and Orbulina universa. G. sacculifer samples collected from a core-top depth transect in the NE Indian Ocean and laboratory dissolution experiments show little if any evidence of preferential removal of Mg-rich calcite layers by progressive dissolution of the tests. We attribute the absence of selective dissolution to the banded distribution of Mg across the chamber walls of these foraminiferal species and to the minimal presence of calcite crusts with relatively low-Mg composition on the outer surfaces of tests. Mg/Ca microanalyses of G. sacculifer from core-top samples further indicate that for samples collected above the calcite lysocline the effect of postdepositional dissolution on Mg/Ca sample mean values is minimal and within the uncertainty of Mg/Ca thermometry (i.e. ±0.4mmol/mol; ±0.8°C at ~28°C). Comparison with previously published results for G. sacculifer supports these observations. Simple modelling of G. sacculifer test dissolution indicates that selective removal of calcite with high-Mg/Ca values from within the final chamber of G. sacculifer test appears insufficient to cause the ~10% decrease in Mg/Ca values observed above calcite lysocline. These changes in test composition might be related to development/removal as a function of Δ[CO32-] of a thin diagenetic surface coating which has a relatively high-Mg/Ca composition (i.e. 20-25mmol/mol). |
format |
Article in Journal/Newspaper |
author |
Sadekov, Aleksey Eggins, Stephen Klinkhammer, G Rosenthal, Y |
author_facet |
Sadekov, Aleksey Eggins, Stephen Klinkhammer, G Rosenthal, Y |
author_sort |
Sadekov, Aleksey |
title |
Effects of seafloor and laboratory dissolution on the Mg/Ca composition of Globigerinoides sacculifer and Orbulina universa tests - A laser ablation ICPMS microanalysis perspective |
title_short |
Effects of seafloor and laboratory dissolution on the Mg/Ca composition of Globigerinoides sacculifer and Orbulina universa tests - A laser ablation ICPMS microanalysis perspective |
title_full |
Effects of seafloor and laboratory dissolution on the Mg/Ca composition of Globigerinoides sacculifer and Orbulina universa tests - A laser ablation ICPMS microanalysis perspective |
title_fullStr |
Effects of seafloor and laboratory dissolution on the Mg/Ca composition of Globigerinoides sacculifer and Orbulina universa tests - A laser ablation ICPMS microanalysis perspective |
title_full_unstemmed |
Effects of seafloor and laboratory dissolution on the Mg/Ca composition of Globigerinoides sacculifer and Orbulina universa tests - A laser ablation ICPMS microanalysis perspective |
title_sort |
effects of seafloor and laboratory dissolution on the mg/ca composition of globigerinoides sacculifer and orbulina universa tests - a laser ablation icpms microanalysis perspective |
publisher |
Elsevier |
url |
http://hdl.handle.net/1885/32722 https://doi.org/10.1016/j.epsl.2010.01.039 https://openresearch-repository.anu.edu.au/bitstream/1885/32722/5/SadekovEggins_Effects_2010.pdf.jpg https://openresearch-repository.anu.edu.au/bitstream/1885/32722/7/01_Sadekov_Effects_of_seafloor_and_2010.pdf.jpg |
geographic |
Indian |
geographic_facet |
Indian |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_source |
Earth and Planetary Science Letters |
op_relation |
0012-821X http://hdl.handle.net/1885/32722 doi:10.1016/j.epsl.2010.01.039 https://openresearch-repository.anu.edu.au/bitstream/1885/32722/5/SadekovEggins_Effects_2010.pdf.jpg https://openresearch-repository.anu.edu.au/bitstream/1885/32722/7/01_Sadekov_Effects_of_seafloor_and_2010.pdf.jpg |
op_doi |
https://doi.org/10.1016/j.epsl.2010.01.039 |
container_title |
Earth and Planetary Science Letters |
container_volume |
292 |
container_issue |
3-4 |
container_start_page |
312 |
op_container_end_page |
324 |
_version_ |
1788064671508463616 |