@Article{Rossetti:2014:RoTeLa,
author = "Rossetti, Dilce de F{\'a}tima",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)}",
title = "The role of tectonics in the late Quaternary evolution of Brazil´s
Amazonian landscape",
journal = "Earth Science Reviews",
year = "2014",
volume = "139",
pages = "362--389",
month = "Dec.",
keywords = "late pleistocene–holocene, amazonian lowland, morphostructural
features, fault reactivation, strike-slip deformation, intraplate
stresses, neotect{\^o}nica, Amaz{\^o}nia, an{\'a}lise
morfoestrutural, pleistoceno tardio, holoceno.",
abstract = "Tectonic reactivation has long been suggested to have occurred
over several areas of the Amazonian lowland in the
NeogeneHolocene. Numerous landscape changes documented in this
region, particularly variations in fluvial dynamics and
morphologies, have nevertheless been exclusively attributed to
climatic fluctuations. Minimizing the effect of tectonics over the
NeogeneHolocene evolution of the Amazon basin can result in a
distorted interpretation of the sedimentary record and, as a
consequence, equivocal paleoclimatic reconstructions. Climate has
often prevailed as a hypothesis to explain changes in fluvial
dynamics possibly due to the still scarce synthesizing
publications focusing exclusively on the neotectonic influence
over this region. The present work provides a review of existing
data focusing on Quaternary tectonics over a large area of the
Amazonian lowland. The existing information is complemented by
original morphostructural data on Quaternary terrains from this
region, which were acquired through remote sensing. The goals were
to analyze the geographic extent of late Quaternary deposits, and
to determine the impact of tectonics on their development and on
the latest evolution of the Amazon drainage basin. The analysis
shows that: 1. the Amazonian lowland experienced geographically
widespread sedimentation in the Late PleistoceneHolocene; 2.
sedimentation was promoted by the creation of new depositional
sites mostly likely resulting from tectonic activity; and 3.
tectonic reactivation impacted the latest evolution of this entire
region, with particular influence on drainage basins, as revealed
by river courses with an abundance of morphostructural lineaments
evidencing fault control. Hence, the NW-, NE-, nearly N-S and, to
a lesser extent, W-E morphostructural trends recorded in all areas
investigated here are generally associated with strike-slip
deformation. In addition, they are conformable with the main
orientation of tectonic structures from adjacent crystalline rocks
of the Precambrian basement. They also match tectonic trends
documented in Neogene and younger sedimentary deposits from this
and several other areas of northeastern Brazil. Furthermore, some
are detected locally in the subsurface by geophysical data.
Furthermore, a profusion of morphostructural anomalies is
imprinted on the surface of NeogeneHolocene deposits of the
Amazonian lowland, the main ones consisting of: 1. highly
asymmetric modern drainage basin still undergoing organization,
with anomalous patterns (i.e., trellis, sub-dendritic,
sub-parallel and rectangular) that often vary from one another,
frequent river captures and rivers flowing in contrary directions
along the time, and straight channels that form triangular shapes
or triple junctions or with local meandering and subtle
enlargements; 2. an abundance of channels, floodplains, lakes and
entire valleys with straight and orthogonal margins that locally
form rhombic shapes or which may be laterally displaced; 3.
fluvial rias (i.e., rivers that became enlarged as their mouth
were barred) bounded by sharp and orthogonal lineaments which
result in rectangular shapes; 4. termination of megafans into
rhombic-shaped depressions bounded by straight lineaments or their
lateral displacement several kilometers apart; and 5. rivers with
asymmetric terraces laterally displaced by faults. These
observations together are consistent with a landscape controlled
by neotectonic activity. The modern seismogenic record, which
reveals even high-magnitude earthquakes, indicates active
deformation over the Amazonian lowland at the Present time. The
neotectonic history of the Amazonian lowland is explained within
the context of an overarching mechanism most likely related to
intraplate stresses. This was probably caused by reactivation of
pre-existing structures since the Neogene that was most likely
promoted by activity along oceanic fracture zones and transform
faults of the Brazilian Equatorial margin, as well as tectonism in
the Andean region.",
doi = "10.1016/j.earscirev.2014.08.009",
url = "http://dx.doi.org/10.1016/j.earscirev.2014.08.009",
issn = "0012-8252",
label = "lattes: 0307721738107549 1 Rossetti:2014:RoTeLa",
language = "pt",
urlaccessdate = "05 maio 2024"
}