The present research was conducted on the northern part of municipality of São Caetano de
Odivelas (PA), which had as objectives identify the relief units, analyze the distribution of
these units from the physiographic conditions, verify the variation of multitemporal position
of the coastline, identify the geoindicators and analyze the consequences for the vegetation
and the morphology that area of study. The methodological procedures of the research
included the bibliographical survey and literature review, cartographic base survey and
products from remote sensors; treatment and digital processing of orbital images, thematic
mapping and field work. Among the morphological units, in this area of study, are the
tabuleiros that totals of 52.7 km ² and are located in the center of this area of study, in the
shape of isolated blocks with a wavy soft relief, where the altimetry ranges from 6 to 30
meters; The plains of muddy tidal add up to 95.9 km ² and will position themselves as sites
parallel to the coastline and along the lower course of rivers, have a flat topography, in which
his altimetry goes 2 to 6 meters; muddy banks of intertidal have 7.3 km ², are positioned so as
planes parallel to the coastline, with slightly angled relief that goes 0 to 2 meters; the sand
ridges subatual add up to 2.2 km ² and are positioned in the shape of arrows arranged as
meaning of the present coastline, with flat topography, with a altimetry 6 to 12 meters;
alluvial plains have 10.7 km ² and are situated in contact with mangrove areas and along some
river channels, with flat topography, above 6 meters; alluvial plains presenting species of
Avicennia sp. have 1.1 km ², feature a flat topography that goes 2 to 6 meters and are found
the interior plains of muddy tidal; alluvial plains with vegetation fields add up to 4.4 km ², are
located shaped places of the narrow valley floors with a flat topography ranges from 4 to 10
meters; the sandy bars have 17.3 km ², are located as deposits elongated in the sense of the
mouths of estuaries and feature a flat topography, which ranges from 0 to 2 meters. The
geomorphological indicators identified are the advance and retreat of the coastline; the
emergence and growth of sandy bars; approach and retraction of sandy bars in relation to the
coastline; the biological indicators relates to formation and destruction of neossolos
mangrove soil; the increase of mangrove area and development of the standard "Escada";
reduction mangrove area and pattern formation "Paliteiro". The morphological changes can be
classified in their majority as acrecionais because in 24 years there was an increase in
mangrove area of 3.85 km ², which responsible for 4.19% of the total area plus in addition to
have occurred in this period, installing two new islands, the Nova and Peruru. The dynamic
that occurs in this municipality cause changes in soil and morphology due to installation of
neossolos and formation of mangrove ecosystem, besides the occurrence of patterns "Escada"
and "Paliteiro".
|
