@Article{RossettiGrReCoMoCoRo:2017:LaHoTe,
author = "Rossetti, Dilce de F{\'a}tima and Gribel, Rog{\'e}rio and
Renn{\'o}, Camilo Daleles and Cohen, Marcelo C. L. and Moulatlet,
Gabriel M. and Cordeiro, Carlos Leandro de Oliveira and Rodrigues,
Erika do Socorro Ferreira",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto
Nacional de Pesquisas da Amaz{\^o}nia (INPA)} and {Instituto
Nacional de Pesquisas Espaciais (INPE)} and {Universidade Federal
do Par{\'a} (UFPA)} and {University of Turku} and {Instituto
Nacional de Pesquisas Espaciais (INPE)} and {Universidade Federal
do Par{\'a} (UFPA)}",
title = "Late Holocene tectonic influence on hydrology and vegetation
patterns in a northern Amazonian megafan",
journal = "Catena",
year = "2017",
volume = "158",
pages = "121--130",
month = "Nov.",
keywords = "Forest canopy, Landscape evolution, Mid/late Holocene, Tectonics,
Northern Amazonia.",
abstract = "The factors that control the heterogeneous canopy of the Amazonian
rainforest have long been a topic of interest for research. Among
all hypotheses, changes in landscape due to geological processes
have been increasingly defended. Large areas of open vegetation in
the northern Amazonian lowlands are confined to paleolandforms
created by the abandoning of megafan depositional systems.
Previous investigations related the megafan sedimentation in this
region to Late Pleistocene-Holocene tectonic reactivations.
However, the influence of neotectonics on both the Amazonian
megafans and associated vegetation cover remains to be further
investigated. We studied a depression preliminarily noticed in the
south-central sector of one Amazonian megafan (i.e., Viru{\'a}
megafan) aiming to determine if its genesis was due to recent
tectonic subsidence after the megafan abandoning. The
investigation combined morphostructural, hydrological and remote
sensing reflectance analyses, as well as characterization of
floristic communities in the modern and ancient environments based
respectively on field inventories and palynological data. The
results indicated a nearly 10-km long and rectangular-shaped area
having straight margins paralleling NNE/SSW-trending regional
structural lineaments. Hydrological analysis suggests that this
area experiences the largest floods during wet seasons, a
condition compatible with the topographic data that revealed a
smoother gradient of ~ 3 m comparing this area with others from
the megafan plain. In the studied depression, numerous forest
patches are arranged as sets of parallel straight lines trending
consistently in the NE/SW direction. The patches have spectral
values that differ significantly from other forest patches over
the megafan surface, being compared to those of seazonally-flooded
forests, such as igap{\'o}s and v{\'a}rzeas, that surround the
megafan paleolandform. In addition, a forest patch within the
depression revealed trees physiologically adapted to tolerate
submersion 6 to 7 months per year, which is also a characteristic
of the inundated forests external to the megafan. These data
altogether led us to conclude that the studied depression consists
of a shallow subsiding basin formed by tectonic reactivations in
the mid/late Holocene. Tectonic instability at around 2 cal kyr BP
further disturbed this system by creating NE/SW-trending lakes and
leading to the replacement of seazonally-flooded forests by
grasslands. Thus, tectonic activity in a relatively recent
geological time must be accounted when analyzing plant
distribution in the Amazonian wetlands.",
doi = "10.1016/j.catena.2017.06.022",
url = "http://dx.doi.org/10.1016/j.catena.2017.06.022",
issn = "0341-8162",
language = "en",
targetfile = "rossetti_late.pdf",
urlaccessdate = "27 abr. 2024"
}