Holocene evolution of a wave-dominated barrier-lagoon system in Rio de Janeiro, Brazil
Silva, R.C.O.; Dias, G.T.M.; Abuchacra, R.C.; de Vasconcelos, S.C.; Macario, K.C.D.; da Fonseca, E.M. (2021). Holocene evolution of a wave-dominated barrier-lagoon system in Rio de Janeiro, Brazil. Radiocarbon 63(4): 1175-1191. https://dx.doi.org/10.1017/rdc.2020.63
In: Radiocarbon. UNIV ARIZONA DEPT GEOSCIENCES: New Haven,. ISSN 0033-8222; e-ISSN 1945-5755, more
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| Keyword |
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| Author keywords |
Barra da Tijuca; coastal barriers; Jacarepaguá coastal plain; paleoenvironmental reconstruction; relative sea-level variations |
| Authors | | Top |
- Silva, R.C.O.
- Dias, G.T.M.
- Abuchacra, R.C.
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- de Vasconcelos, S.C.
- Macario, K.C.D.
- da Fonseca, E.M.
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| Abstract |
In a wave-dominated coast, most of the Jacarepaguá coastal plain is occupied by buildings. During a new construction in this region at Barra da Tijuca, the subsurface area was excavated, exposing its quartzose sand nature, with a high mollusk shell concentration and in situ echinoderms at –10 m depth. The possibility to access this area encouraged us to investigate the evolution of the coastal plain. A 7.84-m-long core was recovered by percussion drilling. Stratigraphic, grain size, and geochemical analysis were undertaken. Three carbonate samples were dated by radiocarbon accelerator mass spectrometry (14C AMS). The revised sea-level variation curve revealed that the last postglacial marine transgression reached the present mean sea-level at 7945–7500 cal BP. The sandy deposit bottom was an ancient shoreface, with in situ echinoderms buried at 7770–7540 cal BP by the Pleistocene inner barrier reworking due to the last marine transgression. The Holocene outer barrier-lagoon and its flood tidal delta were formed from 5440–5070 cal BP. Mid-Holocene marine regression allowed the outer barrier progradation and the lagoon shallowing/infill. This paper confirms prior models proposed by other researchers for the Rio de Janeiro central coast and shows its similarity with the New South Wales coast, Australia. |
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