@Article{RossettiVale:2021:HaAmLo,
author = "Rossetti, Dilce de F{\'a}tima and Valeriano, M{\'a}rcio de
Morisson",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto
Nacional de Pesquisas Espaciais (INPE)}",
title = "Have the Amazonian lowlands evidenced late Pleistocene-Holocene
compression?",
journal = "Journal of South American Earth Sciences",
year = "2021",
volume = "107",
pages = "e103044",
month = "Apr.",
keywords = "Digital elevation model, Relief, Folds, Strike-slip fault,
Pleistocene-Holocene, Amazonia.",
abstract = "Neotectonic reactivation has been increasingly documented in many
areas of the Amazonian lowlands, but the evidence has been only
for extensional structures. This work investigates a large-scale
sinusoidal-shaped morphology (Ssm) in a relief dominated by Late
Quaternary deposits in the north of the Solim{\~o}es Basin. The
digital elevation model (DEM) of the shuttle radar topography
mission (SRTM) was used as a basis to characterize this structure
and improve the knowledge of its geological context. The Ssm is a
Z-shaped sinusoid with a wavelength of approximately 135 km,
formed by two merged asymmetrical curves. The north curve has an
amplitude of 70 km and a core topographically lower and
geologically younger than the limbs, while the south curve has an
amplitude of 90 km and a core with older geological units and
higher relief than the limbs. A main NE-trending morphostructural
lineament has horizontally displaced the rocks near the axial
plane in the north curve. Several NW-trending lineaments that
laterally displaced the modern and ancient valley segments are
also described. Our morphological data led to hypothesize that the
Ssm north and south curves record a plunged syncline and an
anticline, respectively, and that the laterally displaced
lineaments are strike-slip faults. Although this type of fault has
already been described in the region, the propagation of folds in
the Pleistocene-Holocene deposits is a new finding. Assuming this
model, the SW- to WSW-plunging folds would suggest a main NW- to
WNW-oriented maximum horizontal compression, activated
contemporaneously or shortly after the Pleistocene-Holocene
deposition. This proposed orientation for the stress field is
interesting because it would reveal a rotation, in this region, of
the main E-W stress field recorded for South America. On the other
hand, the suggested NW- to WNW-oriented compression is compatible
with the models based on earthquake focal mechanisms comparing
data from Brazil and the sub-Andean region. As such, the present
work can bring new insights to discuss the impact of the late
stage displacement of the South American plate in an intraplate
region away from the passive margin, although the contribution of
local stresses must be also considered.",
doi = "10.1016/j.jsames.2020.103044",
url = "http://dx.doi.org/10.1016/j.jsames.2020.103044",
issn = "0895-9811",
language = "en",
targetfile = "rossetti_have.pdf",
urlaccessdate = "04 maio 2024"
}