cene, under the prevailing semi-arid climate subject to sporadic
and torrential rains, the sedimentation of Barreiras Formation
would have occurred; the sea level should be lower than the cur-
rent one, allowing the sediments of this formation to completely
cover part of the continental shelf. Stage 2: the climate becomes
more humid; already in the Pleistocene, there must have been a
transgression, eroding the external part of Barreiras Formation
and forming a line of cliffs. In many places, these cliffs were
eroded during the penultimate and last transgressions. Stage 3:
in the regressive phase subsequent to the maximum of the ante-
penultimate transgression, the climate seems to have returned
to semiarid at least in the states of Bahia, Sergipe and Alagoas.
This return to conditions similar to that of the deposition of the
Barreiras Formation led to the sedimentation of new continen-
tal deposits at the foothills of scarps, now lower, carved in the
sediments of the Barreiras Formation. In the north-northwest-
ern Fluminense, no evidence of this phase is known. It is proba-
ble that they were eroded during the penultimate transgression,
which also made the old line of cliffs disappear. Stage 4: corre-
sponds to the maximum of the penultimate transgression (with
the maximum maximorum level reached about 123,000 years
BP), when the sea eroded all or part of the continental deposits
of the previous stage. The low courses of the river valleys were
drowned giving rise to estuaries and lagoons. The sediments of
the Barreiras Formation were again eroded, forming a new line
of cliffs. Stage 5: during the subsequent regression, the Pleis-
tocene sandy terraces formed by progradational beach ridges
were constructed. Stage 6: maximum of the last transgression
(5,100 years BP), when the sea must have totally or partially
eroded the Pleistocene marine terraces, with the drowning of
the external Barreiras Formation and of the Pleistocene Plains,
forming lagoon systems. The constitution of barrier-islands
isolated from direct contact with the open sea testimonies of
ancient marine terraces or ancient cliffs carved in the sediments
of Barreiras Formation. Lagoons appear behind the barrier-is-
land line. These islands were already installed before the peak
of the last transgression. When a river flows into these lagoons,
intralagunal deltas begin to develop. Stage 7: There is a further
lowering of the relative sea level, following the last transgressive
maximum, resulting in the construction of marine terraces from
the original barrier-islands when they existed, either directly
from the Pleistocene terraces or still from the cliffs carved in
sediments of the Barreiras Formation. There is a gradual trans-
formation of the lagoons into freshwater lakes and finally into
marshes. There are also fluctuations of the marine level of small
amplitude and short duration after 5,100 years BP.
The author would like to note that the studies carried out
in the coastal plain of Paraíba do Sul by Lamego(37) and Lacer-
da et al(40).considered the climate, fluctuations in river discharge
and sedimentary load, processes associated with river mouth,
wave energy, tidal regime, winds, coastal currents, slope of the
platform, tectonics and geometry of the receiving basin. None,
however, considered the role played by sea level fluctuations.Considering stages 6 and 7, corresponding to the lat-
est marine transgression and regression, the new explanation
identifies, between the maximum of the last transgression and
the current situation, twelve moments of small transgressions
and regressions that are not possible to detail in a revision and
synthesis work. It seems sufficient to say that the marine trans-
gression on the Pliocene tablelands between Quissamã and
Manguinhos began previously at 5,100 years BP, again eroding
the external part of the restingas and Barreiras Formation, cre-
ating cliffs in the form of barrier-islands. These islands formed
a dotted line near the current coastline. Internally, a lagoon with
some openings to the sea was formed. Subsequently, Paraíba
do Sul River starts to flow into this lagoon.After the last transgressive maximum, about 5,100 years
BP, the sea begins its descent, allowing the Paraíba River to pro-
grade in the interior of the semi-open lagoon. To the north of the
future Cape of São Tomé, a concavity produces the accumula-
tion of sand propelled by waves coming from the south, begin-
ning the formation of the northern restinga. Inside the lagoon,
the Paraíba arms continue to deposit sediments brought from
high parts and advancing without reaching the open ocean, un-
til, before 4,200 years BP, when there is a sudden lowering of the
sea level, one of the arms of the inter-lagoon delta of Paraíba
do Sul reaches the open sea, near the current mouth. This arm
acts as a dam for the sand, increasing the progradation of the
northern restinga.Subsequently, a sequence of periods of transgression
and regression, erosion and construction eventually consolidate
the oceanic estuary of Paraíba do Sul and the northern restinga,
the largest in the state of Rio de Janeiro. Gradually, the interi-
or lagoon is being filled by the inter-lagoon delta progradation,
leading to the formation of lagoons, such as Salgada, das Os-
tras, Flecha, Mololô and others. The oceanic arm of the Paraíba
do Sul acts as a hydraulic spike that retains sand on the south
bank of its mouth and, apparently, deposits sediments on the
north bank.Once the interior lagoon is filled and the barrier-islands
are welded, lagoons and a continuous strip of restinga between
Quissamã and Manguinhos are formed, although with different
widths. The coastline, which was more retreated, is closer to the
physiognomy it presents today. At one point, it even exceeded
the current line, especially near the Cape of São Tomé, where its
retreat originated reefs found in that point until today.