Quartz OSL sensitivity from dating data for provenance analysis of pleistocene and holocene fluvial sediments from lowland Amazonia

Autor(es)

Souza, Priscila E. ; Pupim, Fabiano N. ; Mazoca, Carlos E. M. ; del Rio, Ian ; Mineli, Thays D. ; Rodrigues, Fernanda C. G. ; Porat, Naomi ; Hartmann, Gelvam A. ; Sawakuchi, Andre O.

• Tipo de documento: Artigo Científico
• Fonte: QUATERNARY GEOCHRONOLOGY; v. 74, p. 10-pg., 2023-01-29.

Resumo

The properties of the quartz luminescence signal have been shown to be a useful tool for sediment provenance analysis. These provenance studies are based on the sensitivity of the fast optically stimulated luminescence (OSL) component, which is also used for sediment dating. Besides the widespread occurrence of quartz in terrigenous sediments, OSL sensitivity can be acquired using relatively fast and low-cost measurements compared to sediment provenance analysis methods based on accessory minerals or isotopes. Additionally, laboratories worldwide already have an extensive database of recorded quartz OSL signals primarily measured for dating studies, and these data could potentially be repurposed for provenance analysis of Quaternary sedi-mentary systems through OSL sensitivity calculation. Here, we investigate the use of OSL quartz signals measured in sediment dating surveys for OSL sensitivity calculation and evaluation of changes in sediment sources. The OSL sensitivity was calculated and expressed as %BOSLF, which corresponds to the percentage of the fast OSL component signal (blue stimulation) to the total OSL curve; such approach is advantageous as it does not require any normalisation of the measured signal intensity to dose or aliquot size (weight). Three sets of samples from Amazonian fluvial sediments are investigated: two sets of Holocene floodplain sediments representing different sediment sources to the Amazonian fluvial system, i.e. the Amazon craton and the Andes Mountain belt, and a set of samples from the Ic ' a Formation, a paleo-fluvial system active during the Pleistocene whose provenance is not fully known. Results show that the quartz OSL signal derived from the first test doses (Tn) applied in dating protocols had the best performance for %BOSLF calculation when compared to results from a measurement protocol designed specifically for sediment provenance analysis. There is significant correlation (R2 = 88) be-tween sensitivities derived from Tn and a specific OSL provenance analysis protocol. The proposed approach indicates to be appropriate for sediment provenance analysis since it is able to discriminate signal differences among samples from known sources: Brazilian cratonic quartz yield high sensitivity values (mean %BOSLF >70), in contrast to the relatively lower values from Andean quartz (mean %BOSLF <50). In general, quartz OSL sensitivities from the Ic ' a Formation samples fall into the same range of modern sediments transported by the Ica ' and Japur ' a rivers draining the Andean Eastern Cordillera of Colombia and Ecuador. We also observe a decrease in quartz OSL sensitivity during the Holocene, notably after 4 ka, with younger deposits showing lower sensi-tivity. Sediment provenance variations are discussed in terms of watershed rearrangement and/or precipitation -driven changes during the Late Pleistocene and Holocene across Amazonia. (AU)

• Processo FAPESP: 20/11047-1 - Caracterização da origem do interflúvio dos rios Orinoco e Amazonas e sua influência nos paleoambientes e diversificação da biota
• Beneficiário: Fabiano do Nascimento Pupim
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 18/12472-8 - Origem e cronologia de substratos arenosos na Amazônia: implicações para evolução quaternária dos ecossistemas de vegetação aberta
• Beneficiário: Fernanda Costa Gonçalves Rodrigues
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 19/20588-9 - Entendendo a interação entre clima e tectônica no Oeste da Amazônia (Bacia do Acre) durante o Quaternário por meio de técnicas de luminescência
• Beneficiário: Ian Aitor Del Rio Garcia
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 21/14022-2 - Reorganização da rede de drenagem do Oeste da Amazônia no Neógeno e Quaternário baseada na proveniência de sedimentos resolvida por técnicas de luminescência
• Beneficiário: Priscila Emerich Souza
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 18/23899-2 - Projeto de Perfuração Transamazônica: origem e evolução das florestas, clima e hidrologia dos trópicos da América do Sul
• Beneficiário: André Oliveira Sawakuchi
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático