Marine Reservoir Corrections on the Southeastern Coast of Brazil: Paired Samples from the Saquarema Shellmound

Alves, Eduardo Queiroz; Macario, Kita C. D.; Souza, Rosa Cristina Corrêa Luz de; Aguilera, Orangel A.; Goulart, Ana Carolina; Scheel-Ybert, Rita; Bachelet, C.; Carvalho, C. A. A. de; Oliveira, Fernanda Midori de; Douka, Katerina

doi:10.2458/azu_rc.57.18404

Cited by 22 publications

(34 citation statements)

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“…The groundfish catches were the result of multi-gear strategies in seasonal fisheries. Radiometric age, geochemical analyses and climate reconstruction of these ichthyoarchaeological remains [ 52 , 53 , 54 , 55 ] were used to supporting our findings.…”

Section: Introductionmentioning

confidence: 68%

“…Data analyses were carried out on LACAMS software developed at the Physics Institute of Universidade Federal Fluminense [ 98 ]. Calibration of otolith radiocarbon dates was performed with OxCal software v 4.2.3 from the Oxford University [ 99 ], using the Marine13 curve [ 100 ] in the 2-sigma range with an offset for local marine reservoir corrections (ΔR 14 C years) according to the following shellmound localities: Saquarema [ 53 ], Manitiba [ 55 ] and Southeastern Brazil [ 101 ]. Cross-comparisons were conducted in the Beta Analytic Inc. laboratory, following standard protocols.…”

Section: Methodsmentioning

confidence: 99%

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The Path towards Endangered Species: Prehistoric Fisheries in Southeastern Brazil

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Brazilian shellmounds are archaeological sites with a high concentration of marine faunal remains. There are more than 2000 sites along the coast of Brazil that range in age from 8,720 to 985 cal BP. Here, we studied the ichthyoarchaeological remains (i.e., cranial/postcranial bones, otoliths, and teeth, among others) at 13 shellmounds on the southern coast of the state of Rio de Janeiro, which are located in coastal landscapes, including a sandy plain with coastal lagoons, rocky islands, islets and rocky bays. We identified patterns of similarity between shellmounds based on fish diversity, the ages of the assemblages, littoral geomorphology and prehistoric fisheries. Our new radiocarbon dating, based on otolith samples, was used for fishery characterization over time. A taxonomical study of the ichthyoarchaeological remains includes a diversity of 97 marine species, representing 37% of all modern species (i.e., 265 spp.) that have been documented along the coast of Rio de Janeiro state. This high fish diversity recovered from the shellmounds is clear evidence of well-developed prehistoric fishery activity that targeted sharks, rays and finfishes in a productive area influenced by coastal marine upwelling. The presence of adult and neonate shark, especially oceanic species, is here interpreted as evidence of prehistoric fisheries capacity for exploitation and possibly overexploitation in nursery areas. Various tools and strategies were used to capture finfish in seasonal fisheries, over rocky reef bottoms and in sandy littoral environments. Massive catches of whitemouth croaker, main target dermersal species of South Atlantic coast, show evidence of a reduction in body size of approximately 28% compared with modern fisheries. Fishery activity involving vulnerable species, especially in nursery areas, could mark the beginning of fish depletion along the southeastern Brazilian coast and the collapse of natural fish populations.

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Section: Introductionmentioning

confidence: 68%

Section: Methodsmentioning

confidence: 99%

The Path towards Endangered Species: Prehistoric Fisheries in Southeastern Brazil

et al. 2016

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“…Chronological assumptions based on disturbed archaeostratigraphic layering, mainly in shellmounds with less than about 2 m in depth, can lead to serious mistakes. Alves et al (2015b), working on MRE in a southeastern Brazilian shellmound, have shown that samples originating from different depths in the site exhibited statistically-indistinguishable ages.…”

Section: Introductionmentioning

confidence: 97%

“…Russell et al (2010) have proposed a statistical approach that takes into account a large number of samples from the same context and different combinations of marineeterrestrial pairs. Another possibility is the use of phase models in the OxCal software, where groups of samples from the same archaeological layers, for example, can be related to each other (Bronk Ramsey and Lee, 2013;Faivre et al, 2015;Alves et al, 2015b;Carvalho et al, 2015;Macario et al, 2015a). Provided that terrestrial samples are calibrated with the atmospheric curve and marine samples with the marine curve, the offset DR can be adjusted to maximize the contemporaneity of the calibrated results.…”

Section: Introductionmentioning

confidence: 98%

The Usiminas shellmound on the Cabo Frio Island: Marine reservoir effect in an upwelling region on the coast of Brazil

Macario

Alves

Chanca

et al. 2016

Quaternary Geochronology

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“…Na região de Saquarema (22° 55′ 12″ S, 42° 30′ 36″ W), outros dois sítios foram estudados: os sambaquis de Manitiba (carvões, moluscos marinhos e terrestres) e Saquarema (moluscos marinhos, otólitos e carvões). Para esses sítios foram obtidos os valores de ∆R=-82 ± 71 anos de 14 C e -140 ± 66 anos de 14 C (Alves et al 2015b), respectivamente. Mais recentemente, Macario et al (2016) realizaram novo estudo no Sambaqui de Usiminas, na Ilha de Cabo Frio, desta vez comparando um grande número de moluscos marinhos e terrestres.…”

Section: O Efeito De Reservatório Marinho Na Costa Do Brasilunclassified

Efeito de reservatório marinho na costa do Brasil

Macario

Alves

2018

ABEQUA

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ResumoEm estudos cronológicos de processos ocorridos nos últimos 50 mil anos, a datação de carbono 14 é a abordagem mais utilizada em todo o mundo. Para permitir a correta interpretação das idades obtidas, faz-se necessária a calibração dos resultados com base em um robusto banco de dados produzido pela comunidade científica na área de radiocarbono. A calibração objetiva, principalmente, considerar as variações na produção e distribuição do 14 C ao longo do tempo e, no caso do ambiente marinho, corrigir ainda que parcialmente o Efeito de Reservatório Marinho (Marine Reservoir Effect -MRE). De fato, dado que a magnitude do fenômeno aumenta com a profundidade e varia espacialmente em função da dinâmica oceânica, a simples calibração com uma curva marinha global é incapaz de lidar com a real variabilidade do efeito, rendendo resultados não acurados. Desse modo, considera-se também uma correção local, denominada ∆R, com valores disponíveis na literatura para diversas regiões do globo. Assim, no procedimento que é atualmente o padrão adotado em estudos cronológicos, a correção local para o MRE antecede a calibração de uma idade de 14 C marinha com a curva global. Aqui objetivamos elencar os valores de ∆R disponíveis para a costa brasileira, mostrando o impacto causado na calibração das idades de radiocarbono e a importância desse tipo de correção para estudos cronológicos baseados na datação de 14 C de material marinho. Discutimos, finalmente, os problemas causados pela falta ou pelo uso equivocado dessa correção. Palavras-chave: radiocarbono; calibração; amostras marinhas; datação AbstractFor chronological studies encompassing periods within the last 50 thousand years, carbon 14 dating is the most used approach. Calibration with a robust data set allows the correct interpretation of obtained ages by considering temporal variations in radiocarbon production and distribution. In the case of marine radiocarbon ages, calibration is also meant to correct for the so-called Marine Reservoir Effect (MRE). Since the magnitude of this phenomenon increases with depth and varies spatially due to ocean dynamics, simple calibration with a global marine curve is incapable of dealing with the real variability of the effect, yielding inaccurate results. Therefore, one must also consider local corrections, termed ∆R, available in the literature for different regions of the globe. Currently, applying local corrections to marine radiocarbon ages prior to calibration with the most recent global marine curve is a standard practice in chronological studies. Here we aim to list available ∆R values for the coast of Brazil, showing their impact on the calibration of radiocarbon ages and the importance of such correction for chronological studies based on the 14 C dating of marine material. Problems arising from the misuse of ∆R values and/or lack of MRE corrections are also discussed.

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Marine Reservoir Corrections on the Southeastern Coast of Brazil: Paired Samples from the Saquarema Shellmound

Cited by 22 publications

References 28 publications

The Path towards Endangered Species: Prehistoric Fisheries in Southeastern Brazil

The Path towards Endangered Species: Prehistoric Fisheries in Southeastern Brazil

The Usiminas shellmound on the Cabo Frio Island: Marine reservoir effect in an upwelling region on the coast of Brazil

Efeito de reservatório marinho na costa do Brasil

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