Benthic Foraminifera as Evidence of Paleoenviromnental Changes between 9400 and 8300 cal YBP at the Jureia-Itatins Ecological Station Paleolagoon (SP, Brasil)

Autor(es)

Silva, Juliana Braga ^[1] ; Duleba, Wania ^[2] ; Sallun, Alethea M. ^[3] ; Suguio, Kenitiro ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Geociencias IGc, BR-05508080 Sao Paulo - Brazil

^[2] Univ Sao Paulo USP Leste, EACH, BR-03828000 Sao Paulo - Brazil

^[3] Secretaria Meio Ambiente Estado Sao Paulo, Inst Geol, BR-04301903 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Coastal Research; v. 30, n. 6, p. 1118-1130, NOV 2014.
• Citações Web of Science: 1

Resumo

Many aspects of the Santos Transgression (similar to 21,227-20,448 to similar to 5558-4558 cal YBP) remain controversial, especially before approximately 7800 cal YBP, because of the paucity of data for the Brazilian coast. In this context, benthic foraminiferal assemblages from between 9400 and 8385 cal YBP were analyzed from the S03 core collected at the Jureia-Itatins Ecological Station (JIES) with the aim of clarifying the behavior of the relative sea level along the Brazilian coast during this period. Microfaunal, taphonomical, and morphometric analyses of these microorganisms permitted recognition of eight paleoenvironmental conditions within the lagoon then existing at JIES. There were four phases of conspicuous marine contributions (9400-9338, 9072-8894, 8656-8641, and 8594-8500 cal YBP) with a climax at 8656 cal YBP, when the environment became more favorable to the growth, preservation, or both of benthic foraminifera. They were intercalated with two phases of prominent continental contributions (9338-9072 and 8500-8385 cal YBP), when there was an increase in the local hydrodynamic gradient at the S03 core sampling site. Furthermore, between 8806 and 8672 cal YBP and between 8625 and 8594 cal YBP, the benthic foraminifera are absent, most likely because of the lower pH of the mixohaline/limnetic waters present when the continental contribution was highest. These different phases of marine and continental contributions could be explained by the higher or lower inflow of seawater to the paleolagoon of the JIES and by changes of the regional rainfall. (AU)

• Processo FAPESP: 08/57035-2 - Reconstituicao paleoambiental de ambientes marinhos das regioes sul e sudeste (rs, sc, sp), baseadas em analises microfaunisticas e geoquimicas de sedimentos.
• Beneficiário: Juliana Braga Silva
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 06/04467-7 - Estação ecológica Juréia Itatins (SP): flutuações de níveis marinhos abaixo do atual no Holoceno
• Beneficiário: Kenitiro Suguio
• Modalidade de apoio: Auxílio à Pesquisa - Regular