Geoacoustic character, sedimentology and chronology of a cross-shelf Holocene sediment deposit off Cabo Frio, Brazil (southwest Atlantic Ocean)

Mendoza, Ursula; Neto, Arthur Ayres; Abuchacra, Rodrigo Coutinho; Barbosa, Cátia F; Figueiredo, Alberto G.; Gomes, Manoela C.; Belem, André L.; Capilla, Ramsés; Albuquerque, Ana Luíza Spadano

doi:10.1007/s00367-014-0370-6

Cited by 17 publications

(8 citation statements)

References 48 publications

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“…The south-eastern Brazilian shelf has frequently been classified as a "starving platform" (Kowsmann and Costa, 1979), with modern sediment cover considered the result of reworking transgressive sediments. Nevertheless, it is worth noting that there are mud depocentres, as defined by Hanebuth et al (2015), in which muddy sedimentation can be significant and Holocene sedimentation rates can be higher than 50 cm kyr −1 (de Mahiques et al, 2011;Mendoza et al, 2014;. The sources of these sediments are still a matter of debate, but a mixture of local and distant sources cannot be ignored (Mendoza et al, 2014).…”

Section: Sediment Sources and Ocean Circulationmentioning

confidence: 99%

Inorganic and organic geochemical fingerprinting of sediment sources and ocean circulation on a complex continental margin (São Paulo Bight, Brazil)

Mahiques¹,

Hanebuth

Nagai

et al. 2017

Ocean Sci.

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Abstract. In this study, we use inorganic (metal) and organic (bulk and molecular) markers in sediment samples of the south-eastern Brazilian margin to investigate the response of geochemical fingerprints to the complex hydrodynamic processes present in the area. Results indicate the potential of export of terrigenous siliciclastic and organic constituents to the upper slope, even in an area with limited fluvial supply.Metal contents and especially the ln(Ti ∕ Al) and ln(Fe ∕ K) ratios make it possible to recognise the extension of shelf sediments toward the upper slope. Potassium, here expressed as ln(K ∕ Sc) and ln(K ∕ Al) ratios used as proxies of illite–kaolinite variations, proved to be an important parameter, especially because it allowed us to decipher the imprint of the northward flow of the Intermediate Western Boundary Current (IWBC) in comparison to the southward flows of the Brazil Current (BC) and Deep Western Boundary Current (DWBC). Using organic matter analyses, we were able to evaluate the extent of terrestrial contributions to the outer shelf and slope, even without the presence of significant fluvial input. In addition, molecular markers signify a slight increase in the input of C4-derived plants to the slope sediments, transported from distant areas by the main alongshore boundary currents, indicating that the terrestrial fraction of the organic matter deposited on the slope has a distinct origin when compared to shelf sediments.

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Section: Sediment Sources and Ocean Circulationmentioning

confidence: 99%

Inorganic and organic geochemical fingerprinting of sediment sources and ocean circulation on a complex continental margin (São Paulo Bight, Brazil)

Mahiques¹,

Hanebuth

Nagai

et al. 2017

Ocean Sci.

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“…More recently researchers have started to examine the response of open coastlines to these same drivers, with particular focus on the response to the Late Pleistocene to Holocene transgression (e.g. Zecchin et al, 2008;Yoo et al, 2014;Mendoza et al, 2014). However, these latter studies have focused exclusively on the current offshore record with relatively few attempts being made to tie together the terrestrial and littoral components of the coastal zone (Bersezio et al, 2007;Stoker et al, 2009;Peterson et al, 2010;Twichell et al, 2010;Vanderburgh et al, 2010;Anderson et al, 2014;Cawthra et al, 2014).…”

Section: Introductionmentioning

confidence: 97%

Late-Pleistocene evolution of the continental shelf of central Israel, a case study from Hadera

et al. 2016

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“…This has confirmed the important role of major reorganization of Atlantic thermohaline circulation in abrupt climate change (Mahiques et al 2005(Mahiques et al , 2007Toledo et al 2007aToledo et al , 2008Nagai et al 2010;Pivel et al 2010Pivel et al , 2013Leonhardt et al 2013;Mendoza et al 2014;Chapori et al 2015). For the southwestern Atlantic, study of planktonic foraminiferal records has suggested that productivity was higher during deglaciation than in the last glacial maximum (LGM) and the Holocene (Toledo et al 2007b), although other studies have shown that productivity peaked during the LGM and the Younger Dryas in the same region (Mahiques et al 2007;Toledo et al 2008).…”

Section: Introductionmentioning

confidence: 60%

Organic biomarker records spanning the last 34,800 years from the southeastern Brazilian upper slope: links between sea surface temperature, displacement of the Brazil Current, and marine productivity

et al. 2016

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Collective assessment of marine and terrigenous organic biomarkers was performed on a sediment core spanning the last 34,800 years on the upper slope southeast of Brazil to verify the signatures of climatic variations in sea surface temperature (SST), marine productivity, and the flux of terrigenous material in this region. This evaluation is based on marine and terrigenous proxies including alkenones, chlorins, aliphatic hydrocarbons, n-alcohols, and fatty acids. This first report of organic biomarker data for this region confirms a correlation between SST, changes in terrigenous organic matter flow into the ocean, and marine productivity over the last 34.8 ka as a response to the displacement of the Brazil Current. Conditions prevailing during marine isotopic stage (MIS) 3 may be considered intermediate between the last glacial maximum (LGM) and the Late Holocene. For MIS 2, a period of low relative sea level, it was verified that the lowest SSTs were associated with the LGM and higher marine productivity. SST increased by up to 4.4°C between the LGM and the Holocene. This reveals synchronicity between SST on the southeastern Brazilian upper slope and the North Atlantic Ocean SST records reported in earlier studies.

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Geoacoustic character, sedimentology and chronology of a cross-shelf Holocene sediment deposit off Cabo Frio, Brazil (southwest Atlantic Ocean)

Cited by 17 publications

References 48 publications

Inorganic and organic geochemical fingerprinting of sediment sources and ocean circulation on a complex continental margin (São Paulo Bight, Brazil)

Inorganic and organic geochemical fingerprinting of sediment sources and ocean circulation on a complex continental margin (São Paulo Bight, Brazil)

Late-Pleistocene evolution of the continental shelf of central Israel, a case study from Hadera

Organic biomarker records spanning the last 34,800 years from the southeastern Brazilian upper slope: links between sea surface temperature, displacement of the Brazil Current, and marine productivity

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