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Previous issue date: 2009-02-27 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Este trabalho tem como objetivo estudar o comportamento das caracter?sticas f?sicoambientais
do sistema Pisa Sal, especificamente, a configura??o batim?trica, a
caracteriza??o faciol?gica e a morfologia de fundo; o padr?o de circula??o das
correntes de mar?s e das propriedades termohalinas; as zonas de eros?o e
sedimenta??o, o volume de material erodido e suas rela??es com a hidrodin?mica; o
transporte de sedimentos, a idade dos sedimentos e a taxa de sedimenta??o. Para
isso, foram realizados levantamentos, meteorol?gico, batim?trico, sonogr?fico,
oceanogr?fico (correntes e propriedades termohalinas), topogr?fico, amostragem de
sedimentos de fundo e suspens?o e data??o por 14C e 210Pb. O sistema Pisa Sal faz
parte do complexo estuarino lagunar Galinhos-Guamar?, localizado no litoral
setentrional do estado do Rio Grande do Norte, no munic?pio de Galinhos-RN, uma
regi?o sob influ?ncia da ind?stria salineira, carcinicultura e ind?stria petrol?fera. As
informa??es meteorol?gicas definem para regi?o um clima seco com temperatura
elevada, precipita??o baixa e ventos fortes e constantes que influenciam sobremaneira
nas altera??es ambientais do sistema. O sistema Pisa Sal apresenta pequenas
dimens?es (extens?o de 8,0 km, largura m?dia de 150 m e profundidade m?xima de -
4,23 m), perfil longitudinal regular, perfil transversal em ?V? (montante) e em ?U?
(jusante), gradiente horizontal e diferentes formas de leito (fundo plano, marcas de
ondas, dunas subaqu?ticas 2D e 3D, superposi??o de formas e rochoso). As f?cies
sedimentares s?o representadas por sedimentos arenosos e lamosos de composi??o
silic?tica, com varia??o na quantidade de gr?nulo e cascalho biodetr?ticos.
Texturalmente, os sedimentos variam de areia muito grossa a silte. As correntes de
mar?s variam de sim?trica a fracamente assim?tricas, com maiores velocidades
durante as vazantes de siz?gia no per?odo de inverno, com dire??es que refletem a
orienta??o dos canais. Os canais artificiais de despesca/drenagem (CDs) apresentam o
mesmo comportamento do canal Pisa Sal, por?m com menor intensidade. As
propriedades termohalinas classificam o sistema Pisa Sal como um canal de mar? com
caracter?sticas hipersalinas, comportamento de um estu?rio inverso (negativo),
verticalmente bem misturado, for?ado, predominantemente, pela mar?, no qual o
processo de difus?o turbulenta da mar? ? respons?vel pelo transporte de sal canal
acima e que provoca a redu??o da salinidade ao longo do ano. A eros?o no canal Pisa
Sal e nos CDs est?o associadas ? margem c?ncava dos meandros causadas por
fen?menos oceanogr?ficos, clim?ticos e antr?picos, entre os quais destacam-se: as
mar?s, as correntes de mar?s, a chuva, o escoamento superficial, o vento, as
ondula??es,a escava??o de canais, a infiltra??o, a composi??o e a manuten??o de
taludes. O transporte de sedimentos de fundo e suspens?o ? controlado pela varia??o
da velocidade das correntes de mar?s. O transporte ? mais eficiente durante as mar?s
de siz?gia e nos ciclos de vazante, causando exporta??o de sedimentos. A idade dos
sedimentos do canal Pisa Sal ? de 1562 ? 22 cal AP e do canal Volta do Sert?o ? 332-
432 ? 25 anos cal AP. A taxa de sedimenta??o nesses dois canais varia de 0,47 e 0,50
cm/ano, respectivamente. As atividades econ?micas da ind?stria salineira, da
carcinicultura e da ind?stria petrol?fera associadas aos fen?menos naturais
(temperatura do ar e n?vel de evapora??o alto, ?ndice de precipita??o baixo, regime de
mesomar?, velocidade alta das correntes de mar?s e a??o dos ventos) s?o
respons?veis pelas altera??es ambientais que ocorrem no sistema Pisa Sal. / The present work has as objective to study the behavior of physical-environmental
characteristics of the Pisa Sal system, particularly the bathymetry, the facies
characterization and the bottom morphology; the pattern of tidal currents circulation and
of the termohalinas properties; the erosion and sedimentation zones, the bulk erosion
and your relationships with the hydrodynamic; the sediments transport, the sediments
age and sedimentation rate. The integrated data set used includes meteorological,
bathymetric, sonographic, oceanographic (currents and termohalinas properties),
topographic and sedimentological data, as well 14C and 210Pb datation. The Pisa Sal
system is part of the Galinhos-Guamar? lagoon-estuarine complex, located in Galinhos,
northern coast of the Rio Grande do Norte state. It is an area under influence of salt
industry, shrimp farming and oil industry. The meteorological data classifies the area
climate as dry, with high temperature, low precipitation and strong and constant winds,
responsible for important environmental alterations in the system. The Pisa Sal system
presents small dimensions (extension of 8,0 km, medium width of 150 m and maximum
depth of -4,23 m), longitudinal profile to regulate, traverse profile in " V " (head) and in "
U " (mouth), horizontal gradient, and different bedforms (e.g. ripples marks, 2D and 3D
sub-aquatic dunes, flat, rocky). The sedimentary facies are represented by siliciclastic
sandy and muddy sediments, with amount variation of biodetritic granule and gravel.
The sediments texture varies from very coarse sand to silt. The tidal currents changes
from weakly asymmetric to symmetrical, with higher speeds during the ebb-spring tide
in the winter period, and directions reflecting the channels orientation. The drainage
artificial channels (CDs) present the same behavior of the Pisa Sal channel, however
with smaller intensity. The thermohaline properties classify the system as a tidal
channel with hyper-saline characteristics, behavior of an inverse estuary (negative
estuary), vertically very mixed, tidal forced, where the turbulent diffusion process is
responsible for the salt transport and by the salinity reduction over the year. The Pisa
Sal channel and CDs erosion are associated to the concave margin of the meandring
channel caused by oceanographical, climatic and anthropic phenomena, which stand
out: tides, tidal currents, rain, superficial drainage, winds, small waves, channels
excavation, infiltration, composition and slope maintenance. The transport of bottom
sediments and suspension is controlled by the speed variation of tidal currents. It is
more efficient during the spring tides and in the ebb cycles, causing sediments exports.
The age of the sediments of the Pisa Sal channel is 1562 ? 22 cal years AP and of the
Volta do Sert?o channel is 332-432 ? 25 cal years AP. The calculated sedimentation
rates in these two channels was 0,47 and 0,50 cm/year, respectively. The economical
activities of the salt industry, shrimp farming and oil industry associated to the natural
phenomena (temperature of the air and high evaporation level, low precipitation index,
mesotidal conditions, high speed of the tidal currents and winds) are responsible for the
environmental alterations in the Pisa Sal system.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/23767 |
| Date | 27 February 2009 |
| Creators | Costa Neto, Le?o Xavier da |
| Contributors | 314819814-04, Lima, Zuleide Maria Carvalho, 443668254-49, Souza Filho, Pedro Walfir Martins e, 367.834.552-20, Ara?jo Filho, Moacyr Cunha de, 371056394-15, Silva, M?rio Pereira da, Vital, Helenice |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM GEODIN?MICA E GEOF?SICA, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Unknown |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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