Trace metal geochemistry of brachiopod calcite: a new window to the past
The Mg/Ca temperature proxy was applied for the first time to seasonality records in calcitic brachiopod shells, using a laser ablation tracking technique on both Recent and fossil material. Seawater temperature calibrations were established using modern Terebratulina retusa from Scottish waters wit...
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ftunivcardiff:oai:https://orca.cardiff.ac.uk:78889 2023-05-15T13:38:38+02:00 Trace metal geochemistry of brachiopod calcite: a new window to the past Butler, Scott 2015 application/pdf https://orca.cardiff.ac.uk/id/eprint/78889/ https://orca.cardiff.ac.uk/id/eprint/78889/1/Scott%2BButler%2BThesis%2B%2BCorrected%2BVersion.pdf https://orca.cardiff.ac.uk/id/eprint/78889/2/Electronic%20T%20%26%20D%20Publication%20Form.pdf en eng https://orca.cardiff.ac.uk/id/eprint/78889/1/Scott%2BButler%2BThesis%2B%2BCorrected%2BVersion.pdf https://orca.cardiff.ac.uk/id/eprint/78889/2/Electronic%20T%20%26%20D%20Publication%20Form.pdf Butler, Scott https://orca.cardiff.ac.uk/view/cardiffauthors/A099708R.html orcid:0000-0002-5603-5689 orcid:0000-0002-5603-5689 2015. Trace metal geochemistry of brachiopod calcite: a new window to the past. PhD Thesis, Cardiff University. Item availability restricted. file <https://orca.cardiff.ac.uk/78889/1/Scott%2BButler%2BThesis%2B%2BCorrected%2BVersion.pdf>file <https://orca.cardiff.ac.uk/78889/2/Electronic%20T%20%26%20D%20Publication%20Form.pdf> QD Chemistry QE Geology Thesis NonPeerReviewed 2015 ftunivcardiff 2022-11-03T23:34:46Z The Mg/Ca temperature proxy was applied for the first time to seasonality records in calcitic brachiopod shells, using a laser ablation tracking technique on both Recent and fossil material. Seawater temperature calibrations were established using modern Terebratulina retusa from Scottish waters with annual temperature variations ~7 °C, and Liothyrella neozelanica from a water depth transect (168–1488 m) off New Zealand. Comparison of intra-shell Mg/Ca with shell δ18O confirms a temperature control on brachiopod Mg/Ca. Preliminary temperature calibrations are: T. retusa Mg/Ca=1.76±0.27e(0.16 ± 0.03)T, R2=0.75 L. neozelanica Mg/Ca=0.49 ± 1.27e(0.2 ± 0.11)T, R2=0.32. The Eocene-Oligocene Transition (EOT) is the first time during the Cenozoic that Antarctica was permanently glaciated. Mg/Ca and δ18O of brachiopod calcite from two New Zealand sites, one Late Eocene and one Early Oligocene, were sampled to assess seasonality over the EOT. Mg/Ca data identify no statistically significant change in seasonality in this area over the EOT. A 1.3 ‰ positive excursion in δ18O is identified: 0.6 ‰ is attributed to global change in δ18Oseawater and 0.7 ‰ to regional change in δ18Oseawater. Surface currents remained the same around New Zealand across the EOT. Summer Mg/Ca seawater temperatures (~21-24°C) in New Zealand are similar to temperatures derived from TEX86 (Site 1172). The Silurian Ireviken Excursion (~428 Ma) is a worldwide δ13C and δ18O isotopic excursion. Atrypa from Gotland, Sweden was sampled from before and after this Llandovery/Wenlock excursion. Mg/Ca and δ18O data indicate no significant change in seawater temperature over this excursion, against a shift of 1.29 ‰ in δ13C. Relative temperature changes between summer and winter Mg/Ca suggest seasonality of 3.5–5.4 °C. Estimated seawater temperature ~37 °C agrees with a recent clumped isotope study. High temperatures obtained in another study may be attributable to sampling that incorporated the outer side half of the secondary layer. Thesis Antarc* Antarctica Cardiff University: ORCA (Online Research @ Cardiff) New Zealand |
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Open Polar |
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Cardiff University: ORCA (Online Research @ Cardiff) |
op_collection_id |
ftunivcardiff |
language |
English |
topic |
QD Chemistry QE Geology |
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QD Chemistry QE Geology Butler, Scott Trace metal geochemistry of brachiopod calcite: a new window to the past |
topic_facet |
QD Chemistry QE Geology |
description |
The Mg/Ca temperature proxy was applied for the first time to seasonality records in calcitic brachiopod shells, using a laser ablation tracking technique on both Recent and fossil material. Seawater temperature calibrations were established using modern Terebratulina retusa from Scottish waters with annual temperature variations ~7 °C, and Liothyrella neozelanica from a water depth transect (168–1488 m) off New Zealand. Comparison of intra-shell Mg/Ca with shell δ18O confirms a temperature control on brachiopod Mg/Ca. Preliminary temperature calibrations are: T. retusa Mg/Ca=1.76±0.27e(0.16 ± 0.03)T, R2=0.75 L. neozelanica Mg/Ca=0.49 ± 1.27e(0.2 ± 0.11)T, R2=0.32. The Eocene-Oligocene Transition (EOT) is the first time during the Cenozoic that Antarctica was permanently glaciated. Mg/Ca and δ18O of brachiopod calcite from two New Zealand sites, one Late Eocene and one Early Oligocene, were sampled to assess seasonality over the EOT. Mg/Ca data identify no statistically significant change in seasonality in this area over the EOT. A 1.3 ‰ positive excursion in δ18O is identified: 0.6 ‰ is attributed to global change in δ18Oseawater and 0.7 ‰ to regional change in δ18Oseawater. Surface currents remained the same around New Zealand across the EOT. Summer Mg/Ca seawater temperatures (~21-24°C) in New Zealand are similar to temperatures derived from TEX86 (Site 1172). The Silurian Ireviken Excursion (~428 Ma) is a worldwide δ13C and δ18O isotopic excursion. Atrypa from Gotland, Sweden was sampled from before and after this Llandovery/Wenlock excursion. Mg/Ca and δ18O data indicate no significant change in seawater temperature over this excursion, against a shift of 1.29 ‰ in δ13C. Relative temperature changes between summer and winter Mg/Ca suggest seasonality of 3.5–5.4 °C. Estimated seawater temperature ~37 °C agrees with a recent clumped isotope study. High temperatures obtained in another study may be attributable to sampling that incorporated the outer side half of the secondary layer. |
format |
Thesis |
author |
Butler, Scott |
author_facet |
Butler, Scott |
author_sort |
Butler, Scott |
title |
Trace metal geochemistry of brachiopod calcite: a new window to the past |
title_short |
Trace metal geochemistry of brachiopod calcite: a new window to the past |
title_full |
Trace metal geochemistry of brachiopod calcite: a new window to the past |
title_fullStr |
Trace metal geochemistry of brachiopod calcite: a new window to the past |
title_full_unstemmed |
Trace metal geochemistry of brachiopod calcite: a new window to the past |
title_sort |
trace metal geochemistry of brachiopod calcite: a new window to the past |
publishDate |
2015 |
url |
https://orca.cardiff.ac.uk/id/eprint/78889/ https://orca.cardiff.ac.uk/id/eprint/78889/1/Scott%2BButler%2BThesis%2B%2BCorrected%2BVersion.pdf https://orca.cardiff.ac.uk/id/eprint/78889/2/Electronic%20T%20%26%20D%20Publication%20Form.pdf |
geographic |
New Zealand |
geographic_facet |
New Zealand |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
https://orca.cardiff.ac.uk/id/eprint/78889/1/Scott%2BButler%2BThesis%2B%2BCorrected%2BVersion.pdf https://orca.cardiff.ac.uk/id/eprint/78889/2/Electronic%20T%20%26%20D%20Publication%20Form.pdf Butler, Scott https://orca.cardiff.ac.uk/view/cardiffauthors/A099708R.html orcid:0000-0002-5603-5689 orcid:0000-0002-5603-5689 2015. Trace metal geochemistry of brachiopod calcite: a new window to the past. PhD Thesis, Cardiff University. Item availability restricted. file <https://orca.cardiff.ac.uk/78889/1/Scott%2BButler%2BThesis%2B%2BCorrected%2BVersion.pdf>file <https://orca.cardiff.ac.uk/78889/2/Electronic%20T%20%26%20D%20Publication%20Form.pdf> |
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1766108969634365440 |