Evaluating and comparing geochemical sampling protocols in dinosaur eggshells

Coimbra, Rute; Moreno-Azanza, Miguel; Ezquerro, Lope; Nuñez-Lahuerta, Carmen; Gasca, José Manuel; Immenhauser, Adrian; Mateus, Octávio; Rocha, Fernando

http://hdl.handle.net/10362/164224

Utilize este identificador para referenciar este registo.

Nome:	Descrição:	Tamanho:	Formato:
Evaluating_and_comparing_geochemical.pdf		2.74 MB	Adobe PDF	Ver/Abrir

Contacte-nos

Autores

Coimbra, Rute

Moreno-Azanza, Miguel

Ezquerro, Lope

Nuñez-Lahuerta, Carmen

Resumo(s)

The geochemical signatures of dinosaur eggshells represent well-established proxies in paleoenvironmental and paleobiological research. The variable sampling procedures reported in the literature, however, deserve attention. In order to evaluate the impact of different sampling methodologies on carbon and oxygen isotope and elemental concentrations, grinding was contrasted with drilling to extract powder samples from eggshell fragments collected at several locations. Eggshell data were further contrasted with surface materials, encasing matrix and compared with independent proxies using petrographic and elemental techniques. Iron and manganese elemental concentrations revealed an enrichment sequence depending on the sampling strategy for the same eggshell fragment. This pattern can be mistaken for a variable state of preservation. In contrast, carbon and oxygen isotope values exhibited only subtle differences and lacked clear trends. This suggests that isotope data are less susceptible to different methodological approaches. It is shown that drilling offers a wider range of possibilities compared to grinding (e.g., faster and less destructive). Additionally, drilled powder samples can confidently be used for elemental and isotope analysis, excluding contamination, thus providing a more accurate set of proxy data from eggshell archives.

Descrição

GeoBioTec Research Group (FCT – Fundação para a Ciência e Tecnologia, Portugal), by project PLEC2021-008203 project, funded by MCIN/AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR” , by Gobierno de Aragón [Group E18: Aragosaurus: Recursos Geológicos y Paleoambientales]; and by project PID2021-122612OB-I00; Spanish Ministry of Science and Innovation MCIN/AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR”,MCIN/AEI/10.13039/5011000110333. M. M-A is the recipient of a Ramon y Cajal contract RYC2021-034473-I. C. N.-L. is the recipient of a Juan de la Cierva-Formación contract FJC2020-044561-I, supported by the MCIN co-financed by the NextGenerationEU/PRTR. Sylvia Riechelmann is thanked for support during geochemical analysis and Cristina Sequeira for assisting SEM analysis. We thank Marcos Aurell (University of Zaragoza- Spain), for providing a vector file of the geological sketch in Fig. S1F . Constructive comments by two anonymous reviewers and editorial guidance provided by Eduardo Koutsoukos are also acknowledged. Publisher Copyright: © 2023 The Author(s)