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| Pereira,Natan S.; Sial,Alcídes N.; Kikuchi,Ruy K.P.; Ferreira,Valderez P.; Ullmann,Clemens V.; Frei,Robert; Cunha,Adriana M.C.. |
| ABSTRACT Coral skeletons contain records of past environmental conditions due to their long life span and well calibrated geochemical signatures. C and O isotope records of corals are especially interesting, because they can highlight multidecadal variability of local climate conditions beyond the instrumental record, with high fidelity and sub-annual resolution. Although, in order to get an optimal geochemical signal in coral skeleton, sampling strategies must be followed. Here we report one of the first coral-based isotopic record from the Equatorial South Atlantic from two colonies of Porites astreoides from the Rocas Atoll (offshore Brazil), a new location for climate reconstruction. We present time series of isotopic variation from profiles along the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coral; Climate change; Rocas Atoll; Carbon and oxygen isotopes; South Atlantic Ocean. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652015000501939 |
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| Lartaud, Franck; De Rafelis, Marc; Oliver, Graham; Krylova, Elena; Dyment, Jerome; Ildefonse, Benoit; Thibaud, Remy; Gente, Pascal; Hoise, Eva; Meistertzheim, Anne-leila; Fouquet, Yves; Gaill, Francoise; Le Bris, Nadine. |
| Hydrothermal circulation at ultramafic-hosted sites supports a large variety of high-and low-temperature hydrothermal vents and associated ecosystems. The discovery of abundant fossil vesicomyid and thyasirid shell accumulations at the ridge crest, approximately 2.5 km east of the active Rainbow vent field on the Mid-Atlantic Ridge (MAR, 36 degrees 13'N), increased our knowledge regarding the diversity of vent communities at slow spreading ridges. Bivalve molluscs of the family Vesicomyidae were represented by the genus Phreagena. Here we present the first record of this genus in the Atlantic Ocean. This second vesicomyid species known from the MAR, Phreagena sp., was found to be associated with a Thyasira species that is affiliated with T. southwardae (at... |
| Tipo: Text |
Palavras-chave: Ultramafic-hosted; Mid-Atlantic Ridge; Bivalve shells; Vesicomyidae; Thyasiridae; Carbon and oxygen isotopes. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00012/12301/9093.pdf |
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| Sierro, Fj; Hodell, Da; Curtis, Jh; Flores, Ja; Reguera, I; Colmenero-hidalgo, E; Barcena, Ma; Grimalt, Jo; Cacho, I; Frigola, J; Canals, M. |
| Down-core samples of planktonic and benthic foraminifera were analyzed for oxygen and carbon isotopes in International Marine Past Global Changes Study (IMAGES) core MD99-2343 in order to study the interactions between climate change in the Northern Hemisphere and the western Mediterranean thermohaline circulation at times of Heinrich events (HE). Our results confirm the antiphase correlation between enhanced North Atlantic Deep Water formation and low ventilation in the Mediterranean. However, this study reveals that this antiphase relationship in deepwater formation between the North Atlantic and Mediterranean was interrupted during times of HE when the injection of large volumes of water from melting icebergs reached the entrance to the Mediterranean.... |
| Tipo: Text |
Palavras-chave: Climatic change; Heinrich events; Mediterranean Sea; Carbon and oxygen isotopes; Thermohaline circulation; Pleistocene. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00232/34354/32759.pdf |
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| Liu, Yujia; Lu, Hailong; Yin, Xijie; Ruffine, Livio; Çağatay, M. Namik; Yang, Hailin; Chen, Chunqing; He, Dong; Zhu, Zhenli; Yalamaz, Burak. |
| Isotopic, mineralogical and elemental analyses have been conducted for the geochemical characteristics of the bulk carbonates in the sediment cores from the Western High and Çınarcık Basin in the Sea of Marmara to investigate the authigenic, biogenic and detrital components and their possible use in paleoceanographic studies. The Western High is a relatively shallow (‐500 to ‐800 m) compressional area characterized by relatively low sedimentation rates (30‐40 cm/kyr) whereas the Çnarcık Basin is a deep (~1250 m) transtentional area represented by high sedimentation rates (>1 m/kyr). Both 87Sr/86Sr and δ18O of bulk carbonates from the Western High exhibit significant variations, increasing steeply from 87Sr/86Sr of 0.708437 to 0.708916 and δ18O of ‐3.2‰... |
| Tipo: Text |
Palavras-chave: Bulk carbonates; Carbon and oxygen isotopes; Strontium isotopes; Transgression; Anaerobic biodegradation; Sea of Marmara. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00514/62518/66821.pdf |
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| Marques,Wanessa S.; Menor,Eldemar de A.; Sial,Alcides N.; Manso,Valdir A.V.; Freire,Satander S.. |
| Specimens of Recent foraminifera of Amphistegina radiata, Peneroplis planatus and Globigerinoides ruber, from fifty samples of surface sediments of the continental margin of the State of Ceará, Brazil, have been analyzed for carbon and oxygen isotopes to investigate oceanographic parameters and determine the values of delta18O of the oceanic water. From a comparison between values of delta18O obtained for ocean water using the linear equations by (Craig and Gordon 1965) and the one by Wolff et al. (1998), it became evident that the former yielded a more reliable value (0.2 SMOW) than the latter. Lower values of delta18O for the ocean water in this continental margin resulted from continental water influence. Values of 18O (-0.3 to -1.5 PDB for benthic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Foraminifers; Carbon and oxygen isotopes; Continental margin; Ceará; Brazil. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652007000100015 |
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