Modern processes of palynomorph deposition at lakes of the northern region of the Rio de Janeiro State, Brazil

Abstract

Palynological analysis of pollen, Pteridophyta spores and algae deposited in the superficial sediments at Lagoa de Cima and Lagoa do Campelo Lakes, located in the north of Rio de Janeiro state, was used to determine the spatial variation of the palynomorphs deposition. A total of 67 pollen types were identified at Lagoa de Cima, with an expressive contribution of regional arboreous taxa, hydrophytes and ruderal plants of the pastureland. The depositional pattern of palynomorphs depends on the fluvial leakage, the proximity of the local sedimentation to the inlet of the Imbé and Urubu Rivers and the bathymetry of lake bottom. The highest concentrations of palynomorphs were observed in the decentralized and less deeper area, without the interference of the northeastern wind. At Lagoa do Campelo, a total of 58 pollen types were identified, among which the majority of the pollen grains came from hydrophytes, with the highest concentrations found along the northeastern shore. The southeastern shore showed high percentages of pollen and spores with degraded exine and mechanical damage, due to the transport through the lake by the currents caused by the wind, confirmed by the depositional trend of damaged palinomorphs along the same direction as the prevailing winds.

Tafonomia de Esporos de Pteridófitas Encontrados em Sedimentos Turfosos Quaternários do Rio de Janeiro, Brasil

“…Os dados percentuais obtidos, apresentando as relações de frequência entre esporos com e sem danos, bem como entre os tipos de danos, representam muito bem as condições ambientais às quais ficaram sujeitos durante sua sedimentação (Luz et al, 2010). Os dados de concentração total de esporos por cm 3 de sedimento por nível amostrado, bem como dos esporos apresentando danos de corrosão e degradação, de danos mecânicos e os sem danos, refletem as condições de sedimentação dos mesmos ao local de deposição e posterior fossilização.…”

Palynology as a Tool in Bathymetry

“…Fifteen surface samples were collected with a hand dredger in the top five centimeters of the Lagoa de Cima Lake sediments and four of the Lagoa do Campelo Lake, in a transect of 500 m steps from one to the opposite side, in the NE/SW direction, which is the same direction of the dominant wind (Luz et al 2002(Luz et al , 2005(Luz et al , 2010.…”

Bathymetry and Its Applications

“…Aiming to support the reconstruction of the temporal dynamics of the vegetation during the last 7,000 years (Luz et al 2011), palynological studies of surface sediment samples were performed to elucidate the current dynamics that have influenced the sedimentation of palynomorphs inside these lakes. Fifteen surface samples were collected with a hand dredger in the top five centimeters of the Lagoa de Cima Lake sediments and four of the Lagoa do Campelo Lake, in a transect of 500 m steps from one to the opposite side, in the NE/SW direction, which is the same direction of the dominant wind (Luz et al 2002(Luz et al , 2005(Luz et al , 2010.…”