Sulfur isotope analysis of collagen: Quality controls and proboscidean wetland habitats

Sulfur isotopes (δ34S values) have significant potential for addressing archaeological, paleontological, and paleoecological research questions. Studies of ancient materials rely on the assumption that δ34S values have been minimally altered by diagenesis, yet meaningful analyses of sulfur isotope p...

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Main Authors: Jessica Z. Metcalfe, Lauryn E. Eady-Sitar, Ayumi Hyodo, Taylor Belot
Format: Article
Language:English
Published: Elsevier 2024-12-01
Series:Quaternary Environments and Humans
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Online Access:http://www.sciencedirect.com/science/article/pii/S2950236524000380
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author Jessica Z. Metcalfe
Lauryn E. Eady-Sitar
Ayumi Hyodo
Taylor Belot
author_facet Jessica Z. Metcalfe
Lauryn E. Eady-Sitar
Ayumi Hyodo
Taylor Belot
author_sort Jessica Z. Metcalfe
collection DOAJ
description Sulfur isotopes (δ34S values) have significant potential for addressing archaeological, paleontological, and paleoecological research questions. Studies of ancient materials rely on the assumption that δ34S values have been minimally altered by diagenesis, yet meaningful analyses of sulfur isotope preservation/alteration are rare. This paper has 3 objectives: (1) to review and revise previous approaches to evaluating sulfur isotope alteration of collagen, (2) to evaluate sulfur isotope preservation in Great Lakes mammoth (Mammuthus spp.) and mastodon (Mammut americanum) bone, tooth, and tusk collagen, and (3) to make inferences about proboscidean diets and habitat preferences based on δ34S values. To evaluate sulfur isotope preservation in collagen we recommend 3 approaches. First, researchers should examine collagen %C, %N, and atomic C:N values, and exclude samples whose values fall outside the expected ranges (defined according to context-specific considerations). Second, researchers should examine collagen %S, C:S, and N:S values, and exclude samples that fall outside the ranges for modern taxa. These ranges are subject to revision, but this study provides a new compilation of modern mammalian collagen with %S = 0.14–0.63, C:S = 185–873, and N:S = 55–266 (n=119). Third, researchers should check for correlations between collagen δ34S and %S, C:S, or N:S values, which could suggest systematic alteration of sulfur isotope values due to sulfur contamination or amino acid loss. For our Great Lakes proboscideans, the first approach was insufficient to identify sulfur isotope alteration, but the second and third approaches led to the exclusion of 4 samples with probable alteration. Great Lakes proboscideans had lower δ34S values than recent taxa from the same region, and the δ34S of mastodons tended to be lower than those of mammoths. These results suggest that mammoths and (to a greater extent) mastodons consumed an abundance of plants rooted in anoxic freshwater wetland sediments.
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spelling doaj-art-407dc75f06434d9fb29dcfcd2921351c2025-08-20T02:36:12ZengElsevierQuaternary Environments and Humans2950-23652024-12-012610004010.1016/j.qeh.2024.100040Sulfur isotope analysis of collagen: Quality controls and proboscidean wetland habitatsJessica Z. Metcalfe0Lauryn E. Eady-Sitar1Ayumi Hyodo2Taylor Belot3Department of Anthropology, Lakehead University, 955 Oliver Rd., Thunder Bay, ON P7B 5E1, Canada; Corresponding author.Department of Anthropology, Lakehead University, 955 Oliver Rd., Thunder Bay, ON P7B 5E1, CanadaDepartment of Ecosystem Science and Management, Texas A&M University, College Station, TX, USADepartment of Anthropology, Lakehead University, 955 Oliver Rd., Thunder Bay, ON P7B 5E1, CanadaSulfur isotopes (δ34S values) have significant potential for addressing archaeological, paleontological, and paleoecological research questions. Studies of ancient materials rely on the assumption that δ34S values have been minimally altered by diagenesis, yet meaningful analyses of sulfur isotope preservation/alteration are rare. This paper has 3 objectives: (1) to review and revise previous approaches to evaluating sulfur isotope alteration of collagen, (2) to evaluate sulfur isotope preservation in Great Lakes mammoth (Mammuthus spp.) and mastodon (Mammut americanum) bone, tooth, and tusk collagen, and (3) to make inferences about proboscidean diets and habitat preferences based on δ34S values. To evaluate sulfur isotope preservation in collagen we recommend 3 approaches. First, researchers should examine collagen %C, %N, and atomic C:N values, and exclude samples whose values fall outside the expected ranges (defined according to context-specific considerations). Second, researchers should examine collagen %S, C:S, and N:S values, and exclude samples that fall outside the ranges for modern taxa. These ranges are subject to revision, but this study provides a new compilation of modern mammalian collagen with %S = 0.14–0.63, C:S = 185–873, and N:S = 55–266 (n=119). Third, researchers should check for correlations between collagen δ34S and %S, C:S, or N:S values, which could suggest systematic alteration of sulfur isotope values due to sulfur contamination or amino acid loss. For our Great Lakes proboscideans, the first approach was insufficient to identify sulfur isotope alteration, but the second and third approaches led to the exclusion of 4 samples with probable alteration. Great Lakes proboscideans had lower δ34S values than recent taxa from the same region, and the δ34S of mastodons tended to be lower than those of mammoths. These results suggest that mammoths and (to a greater extent) mastodons consumed an abundance of plants rooted in anoxic freshwater wetland sediments.http://www.sciencedirect.com/science/article/pii/S2950236524000380Sulfur isotopesBoneCollagenDiagenesisProboscidean
spellingShingle Jessica Z. Metcalfe
Lauryn E. Eady-Sitar
Ayumi Hyodo
Taylor Belot
Sulfur isotope analysis of collagen: Quality controls and proboscidean wetland habitats
Quaternary Environments and Humans
Sulfur isotopes
Bone
Collagen
Diagenesis
Proboscidean
title Sulfur isotope analysis of collagen: Quality controls and proboscidean wetland habitats
title_full Sulfur isotope analysis of collagen: Quality controls and proboscidean wetland habitats
title_fullStr Sulfur isotope analysis of collagen: Quality controls and proboscidean wetland habitats
title_full_unstemmed Sulfur isotope analysis of collagen: Quality controls and proboscidean wetland habitats
title_short Sulfur isotope analysis of collagen: Quality controls and proboscidean wetland habitats
title_sort sulfur isotope analysis of collagen quality controls and proboscidean wetland habitats
topic Sulfur isotopes
Bone
Collagen
Diagenesis
Proboscidean
url http://www.sciencedirect.com/science/article/pii/S2950236524000380
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